diff --git a/rust/Cargo.lock b/rust/Cargo.lock
index bb0768afe..6a56f923d 100644
--- a/rust/Cargo.lock
+++ b/rust/Cargo.lock
@@ -155,9 +155,9 @@ version = "0.3.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "16e62a023e7c117e27523144c5d2459f4397fcc3cab0085af8e2224f643a0193"
 dependencies = [
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "quote 1.0.36",
- "syn 2.0.59",
+ "syn 2.0.60",
 ]
 
 [[package]]
@@ -166,9 +166,9 @@ version = "0.1.80"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c6fa2087f2753a7da8cc1c0dbfcf89579dd57458e36769de5ac750b4671737ca"
 dependencies = [
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "quote 1.0.36",
- "syn 2.0.59",
+ "syn 2.0.60",
 ]
 
 [[package]]
@@ -592,10 +592,10 @@ checksum = "9c2cf1c23a687a1feeb728783b993c4e1ad83d99f351801977dd809b48d0a70f"
 dependencies = [
  "fnv",
  "ident_case",
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "quote 1.0.36",
  "strsim 0.10.0",
- "syn 2.0.59",
+ "syn 2.0.60",
 ]
 
 [[package]]
@@ -606,7 +606,7 @@ checksum = "a668eda54683121533a393014d8692171709ff57a7d61f187b6e782719f8933f"
 dependencies = [
  "darling_core",
  "quote 1.0.36",
- "syn 2.0.59",
+ "syn 2.0.60",
 ]
 
 [[package]]
@@ -625,7 +625,7 @@ version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7a2c35ab6e03642397cdda1dd58abbc05d418aef8e36297f336d5aba060fe8df"
 dependencies = [
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "quote 1.0.36",
  "syn 1.0.109",
 ]
@@ -864,9 +864,9 @@ version = "0.3.30"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "87750cf4b7a4c0625b1529e4c543c2182106e4dedc60a2a6455e00d212c489ac"
 dependencies = [
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "quote 1.0.36",
- "syn 2.0.59",
+ "syn 2.0.60",
 ]
 
 [[package]]
@@ -1161,9 +1161,9 @@ dependencies = [
 
 [[package]]
 name = "hyper"
-version = "1.3.0"
+version = "1.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9f24ce812868d86d19daa79bf3bf9175bc44ea323391147a5e3abde2a283871b"
+checksum = "fe575dd17d0862a9a33781c8c4696a55c320909004a67a00fb286ba8b1bc496d"
 dependencies = [
  "bytes",
  "futures-channel",
@@ -1202,7 +1202,7 @@ checksum = "a0bea761b46ae2b24eb4aef630d8d1c398157b6fc29e6350ecf090a0b70c952c"
 dependencies = [
  "futures-util",
  "http 1.1.0",
- "hyper 1.3.0",
+ "hyper 1.3.1",
  "hyper-util",
  "rustls 0.22.3",
  "rustls-pki-types",
@@ -1234,7 +1234,7 @@ dependencies = [
  "futures-util",
  "http 1.1.0",
  "http-body 1.0.0",
- "hyper 1.3.0",
+ "hyper 1.3.1",
  "pin-project-lite",
  "socket2",
  "tokio",
@@ -1492,10 +1492,10 @@ checksum = "dc487311295e0002e452025d6b580b77bb17286de87b57138f3b5db711cded68"
 dependencies = [
  "beef",
  "fnv",
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "quote 1.0.36",
  "regex-syntax 0.6.29",
- "syn 2.0.59",
+ "syn 2.0.60",
 ]
 
 [[package]]
@@ -1662,7 +1662,7 @@ version = "0.9.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "197eff6c12b80ff5de6173e438fa3c1340a9e708118c1626e690f65aee1e5332"
 dependencies = [
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "quote 1.0.36",
  "syn 1.0.109",
 ]
@@ -1674,7 +1674,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ef492b5cf80f90c050b287e747228a1fa6517e9d754f364b5a7e0e038e49a25f"
 dependencies = [
  "proc-macro-crate",
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "quote 1.0.36",
  "syn 1.0.109",
 ]
@@ -2162,7 +2162,7 @@ dependencies = [
  "bytes",
  "chrono",
  "chrono-tz 0.8.6",
- "env_logger 0.10.2",
+ "env_logger 0.11.3",
  "expectest",
  "fs2",
  "gregorian",
@@ -2185,7 +2185,7 @@ dependencies = [
  "regex",
  "regex-syntax 0.6.29",
  "reqwest 0.11.27",
- "rstest 0.17.0",
+ "rstest 0.19.0",
  "semver",
  "serde",
  "serde_json",
@@ -2402,9 +2402,9 @@ version = "1.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2f38a4412a78282e09a2cf38d195ea5420d15ba0602cb375210efbc877243965"
 dependencies = [
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "quote 1.0.36",
- "syn 2.0.59",
+ "syn 2.0.60",
 ]
 
 [[package]]
@@ -2459,8 +2459,8 @@ version = "0.2.19"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5ac2cf0f2e4f42b49f5ffd07dae8d746508ef7526c13940e5f524012ae6c6550"
 dependencies = [
- "proc-macro2 1.0.80",
- "syn 2.0.59",
+ "proc-macro2 1.0.81",
+ "syn 2.0.60",
 ]
 
 [[package]]
@@ -2483,9 +2483,9 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.80"
+version = "1.0.81"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a56dea16b0a29e94408b9aa5e2940a4eedbd128a1ba20e8f7ae60fd3d465af0e"
+checksum = "3d1597b0c024618f09a9c3b8655b7e430397a36d23fdafec26d6965e9eec3eba"
 dependencies = [
  "unicode-ident",
 ]
@@ -2517,7 +2517,7 @@ dependencies = [
  "prost",
  "prost-types",
  "regex",
- "syn 2.0.59",
+ "syn 2.0.60",
  "tempfile",
 ]
 
@@ -2529,9 +2529,9 @@ checksum = "19de2de2a00075bf566bee3bd4db014b11587e84184d3f7a791bc17f1a8e9e48"
 dependencies = [
  "anyhow",
  "itertools 0.12.1",
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "quote 1.0.36",
- "syn 2.0.59",
+ "syn 2.0.60",
 ]
 
 [[package]]
@@ -2578,7 +2578,7 @@ version = "1.0.36"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0fa76aaf39101c457836aec0ce2316dbdc3ab723cdda1c6bd4e6ad4208acaca7"
 dependencies = [
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
 ]
 
 [[package]]
@@ -2759,7 +2759,7 @@ dependencies = [
  "http 1.1.0",
  "http-body 1.0.0",
  "http-body-util",
- "hyper 1.3.0",
+ "hyper 1.3.1",
  "hyper-rustls 0.26.0",
  "hyper-util",
  "ipnet",
@@ -2804,18 +2804,6 @@ dependencies = [
  "windows-sys 0.52.0",
 ]
 
-[[package]]
-name = "rstest"
-version = "0.17.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "de1bb486a691878cd320c2f0d319ba91eeaa2e894066d8b5f8f117c000e9d962"
-dependencies = [
- "futures",
- "futures-timer",
- "rstest_macros 0.17.0",
- "rustc_version",
-]
-
 [[package]]
 name = "rstest"
 version = "0.18.2"
@@ -2840,20 +2828,6 @@ dependencies = [
  "rustc_version",
 ]
 
-[[package]]
-name = "rstest_macros"
-version = "0.17.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "290ca1a1c8ca7edb7c3283bd44dc35dd54fdec6253a3912e201ba1072018fca8"
-dependencies = [
- "cfg-if",
- "proc-macro2 1.0.80",
- "quote 1.0.36",
- "rustc_version",
- "syn 1.0.109",
- "unicode-ident",
-]
-
 [[package]]
 name = "rstest_macros"
 version = "0.18.2"
@@ -2862,12 +2836,12 @@ checksum = "d428f8247852f894ee1be110b375111b586d4fa431f6c46e64ba5a0dcccbe605"
 dependencies = [
  "cfg-if",
  "glob",
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "quote 1.0.36",
  "regex",
  "relative-path",
  "rustc_version",
- "syn 2.0.59",
+ "syn 2.0.60",
  "unicode-ident",
 ]
 
@@ -2879,12 +2853,12 @@ checksum = "04a9df72cc1f67020b0d63ad9bfe4a323e459ea7eb68e03bd9824db49f9a4c25"
 dependencies = [
  "cfg-if",
  "glob",
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "quote 1.0.36",
  "regex",
  "relative-path",
  "rustc_version",
- "syn 2.0.59",
+ "syn 2.0.60",
  "unicode-ident",
 ]
 
@@ -3090,22 +3064,22 @@ checksum = "92d43fe69e652f3df9bdc2b85b2854a0825b86e4fb76bc44d945137d053639ca"
 
 [[package]]
 name = "serde"
-version = "1.0.197"
+version = "1.0.198"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3fb1c873e1b9b056a4dc4c0c198b24c3ffa059243875552b2bd0933b1aee4ce2"
+checksum = "9846a40c979031340571da2545a4e5b7c4163bdae79b301d5f86d03979451fcc"
 dependencies = [
  "serde_derive",
 ]
 
 [[package]]
 name = "serde_derive"
-version = "1.0.197"
+version = "1.0.198"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7eb0b34b42edc17f6b7cac84a52a1c5f0e1bb2227e997ca9011ea3dd34e8610b"
+checksum = "e88edab869b01783ba905e7d0153f9fc1a6505a96e4ad3018011eedb838566d9"
 dependencies = [
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "quote 1.0.36",
- "syn 2.0.59",
+ "syn 2.0.60",
 ]
 
 [[package]]
@@ -3165,9 +3139,9 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6561dc161a9224638a31d876ccdfefbc1df91d3f3a8342eddb35f055d48c7655"
 dependencies = [
  "darling",
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "quote 1.0.36",
- "syn 2.0.59",
+ "syn 2.0.60",
 ]
 
 [[package]]
@@ -3356,18 +3330,18 @@ version = "1.0.109"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "72b64191b275b66ffe2469e8af2c1cfe3bafa67b529ead792a6d0160888b4237"
 dependencies = [
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "quote 1.0.36",
  "unicode-ident",
 ]
 
 [[package]]
 name = "syn"
-version = "2.0.59"
+version = "2.0.60"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4a6531ffc7b071655e4ce2e04bd464c4830bb585a61cabb96cf808f05172615a"
+checksum = "909518bc7b1c9b779f1bbf07f2929d35af9f0f37e47c6e9ef7f9dddc1e1821f3"
 dependencies = [
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "quote 1.0.36",
  "unicode-ident",
 ]
@@ -3380,9 +3354,9 @@ checksum = "2047c6ded9c721764247e62cd3b03c09ffc529b2ba5b10ec482ae507a4a70160"
 
 [[package]]
 name = "sysinfo"
-version = "0.30.10"
+version = "0.30.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "26d7c217777061d5a2d652aea771fb9ba98b6dade657204b08c4b9604d11555b"
+checksum = "87341a165d73787554941cd5ef55ad728011566fe714e987d1b976c15dbc3a83"
 dependencies = [
  "cfg-if",
  "core-foundation-sys",
@@ -3452,7 +3426,7 @@ version = "0.2.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "877189d680101869f65ef94168105d6c188b3a143c13a2d42cf8a09c4c704f8a"
 dependencies = [
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "quote 1.0.36",
  "syn 1.0.109",
 ]
@@ -3474,9 +3448,9 @@ version = "0.2.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c8f546451eaa38373f549093fe9fd05e7d2bade739e2ddf834b9968621d60107"
 dependencies = [
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "quote 1.0.36",
- "syn 2.0.59",
+ "syn 2.0.60",
 ]
 
 [[package]]
@@ -3503,9 +3477,9 @@ version = "1.0.58"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c61f3ba182994efc43764a46c018c347bc492c79f024e705f46567b418f6d4f7"
 dependencies = [
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "quote 1.0.36",
- "syn 2.0.59",
+ "syn 2.0.60",
 ]
 
 [[package]]
@@ -3601,9 +3575,9 @@ version = "2.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5b8a1e28f2deaa14e508979454cb3a223b10b938b45af148bc0986de36f1923b"
 dependencies = [
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "quote 1.0.36",
- "syn 2.0.59",
+ "syn 2.0.60",
 ]
 
 [[package]]
@@ -3674,7 +3648,7 @@ dependencies = [
  "serde",
  "serde_spanned",
  "toml_datetime",
- "toml_edit 0.22.9",
+ "toml_edit 0.22.11",
 ]
 
 [[package]]
@@ -3699,9 +3673,9 @@ dependencies = [
 
 [[package]]
 name = "toml_edit"
-version = "0.22.9"
+version = "0.22.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8e40bb779c5187258fd7aad0eb68cb8706a0a81fa712fbea808ab43c4b8374c4"
+checksum = "fb686a972ccef8537b39eead3968b0e8616cb5040dbb9bba93007c8e07c9215f"
 dependencies = [
  "indexmap 2.2.6",
  "serde",
@@ -3771,10 +3745,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9d021fc044c18582b9a2408cd0dd05b1596e3ecdb5c4df822bb0183545683889"
 dependencies = [
  "prettyplease",
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "prost-build",
  "quote 1.0.36",
- "syn 2.0.59",
+ "syn 2.0.60",
 ]
 
 [[package]]
@@ -3784,10 +3758,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "be4ef6dd70a610078cb4e338a0f79d06bc759ff1b22d2120c2ff02ae264ba9c2"
 dependencies = [
  "prettyplease",
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "prost-build",
  "quote 1.0.36",
- "syn 2.0.59",
+ "syn 2.0.60",
 ]
 
 [[package]]
@@ -3852,9 +3826,9 @@ version = "0.1.27"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "34704c8d6ebcbc939824180af020566b01a7c01f80641264eba0999f6c2b6be7"
 dependencies = [
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "quote 1.0.36",
- "syn 2.0.59",
+ "syn 2.0.60",
 ]
 
 [[package]]
@@ -3936,7 +3910,7 @@ dependencies = [
  "serde",
  "shlex",
  "snapbox",
- "toml_edit 0.22.9",
+ "toml_edit 0.22.11",
 ]
 
 [[package]]
@@ -4065,7 +4039,7 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d257817081c7dffcdbab24b9e62d2def62e2ff7d00b1c20062551e6cccc145ff"
 dependencies = [
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "quote 1.0.36",
 ]
 
@@ -4122,9 +4096,9 @@ dependencies = [
  "bumpalo",
  "log",
  "once_cell",
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "quote 1.0.36",
- "syn 2.0.59",
+ "syn 2.0.60",
  "wasm-bindgen-shared",
 ]
 
@@ -4156,9 +4130,9 @@ version = "0.2.92"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e94f17b526d0a461a191c78ea52bbce64071ed5c04c9ffe424dcb38f74171bb7"
 dependencies = [
- "proc-macro2 1.0.80",
+ "proc-macro2 1.0.81",
  "quote 1.0.36",
- "syn 2.0.59",
+ "syn 2.0.60",
  "wasm-bindgen-backend",
  "wasm-bindgen-shared",
 ]
diff --git a/rust/pact_consumer/src/builders/request_builder.rs b/rust/pact_consumer/src/builders/request_builder.rs
index 9779a578a..d6b4e05ec 100644
--- a/rust/pact_consumer/src/builders/request_builder.rs
+++ b/rust/pact_consumer/src/builders/request_builder.rs
@@ -132,7 +132,7 @@ impl RequestBuilder {
             .get_defaulting()
             .entry(key.clone())
             .or_insert_with(Default::default)
-            .push(value.to_example());
+            .push(Some(value.to_example()));
 
         let mut path = DocPath::root();
         path.push_field(key);
diff --git a/rust/pact_ffi/src/log/sink.rs b/rust/pact_ffi/src/log/sink.rs
index b7d248730..3e1b7f7ca 100644
--- a/rust/pact_ffi/src/log/sink.rs
+++ b/rust/pact_ffi/src/log/sink.rs
@@ -17,6 +17,7 @@ use crate::log::inmem_buffer::InMemBuffer;
 
 /// A sink for logs to be written to, based on a provider specifier.
 #[derive(Debug)]
+#[allow(dead_code)]
 pub(crate) enum Sink {
     /// Write logs to stdout.
     Stdout(Stdout),
diff --git a/rust/pact_ffi/src/mock_server/handles.rs b/rust/pact_ffi/src/mock_server/handles.rs
index 392fbd756..0519f97d2 100644
--- a/rust/pact_ffi/src/mock_server/handles.rs
+++ b/rust/pact_ffi/src/mock_server/handles.rs
@@ -771,11 +771,11 @@ pub extern fn pactffi_with_query_parameter(
             if index >= values.len() {
               values.resize_with(index + 1, Default::default);
             }
-            values[index] = value;
+            values[index] = Some(value);
           } else {
-            let mut values: Vec<String> = Vec::new();
+            let mut values: Vec<Option<String>> = Vec::new();
             values.resize_with(index + 1, Default::default);
-            values[index] = value;
+            values[index] = Some(value);
             q.insert(name.to_string(), values);
           };
           q
@@ -784,9 +784,9 @@ pub extern fn pactffi_with_query_parameter(
           path.push_field(name).push_index(index);
           #[allow(deprecated)]
           let value = from_integration_json(&mut reqres.request.matching_rules, &mut reqres.request.generators, &value.to_string(), path, "query");
-          let mut values: Vec<String> = Vec::new();
+          let mut values: Vec<Option<String>> = Vec::new();
           values.resize_with(index + 1, Default::default);
-          values[index] = value;
+          values[index] = Some(value);
           Some(hashmap! { name.to_string() => values })
         });
         !mock_server_started
@@ -839,8 +839,12 @@ pub extern fn pactffi_with_query_parameter(
 /// const char* value = "{\"value\":[\"2\"], \"pact:matcher:type\":\"regex\", \"regex\":\"\\\\d+\"}";
 /// pactffi_with_query_parameter_v2(handle, "id", 0, value);
 /// ```
+///
+/// For a query parameter with no value, the value parameter can be set to a NULL pointer.
+///
 /// # Safety
-/// The name and value parameters must be valid pointers to NULL terminated strings.
+/// The name parameter must be a valid pointer to a NULL terminated string. If the value
+/// parameter is not NULL, it must point to a valid NULL terminated string.
 /// ```
 #[no_mangle]
 pub extern fn pactffi_with_query_parameter_v2(
@@ -850,7 +854,7 @@ pub extern fn pactffi_with_query_parameter_v2(
   value: *const c_char
 ) -> bool {
   if let Some(name) = convert_cstr("name", name) {
-    let value = convert_cstr("value", value).unwrap_or_default();
+    let value = convert_cstr("value", value);
     trace!(?interaction, name, index, value, "pactffi_with_query_parameter_v2 called");
     interaction.with_interaction(&|_, mock_server_started, inner| {
       if let Some(reqres) = inner.as_v4_http_mut() {
@@ -860,31 +864,38 @@ pub extern fn pactffi_with_query_parameter_v2(
           path.push_index(index);
         }
 
-        let value = from_integration_json_v2(
-          &mut reqres.request.matching_rules,
-          &mut reqres.request.generators,
-          value,
-          path,
-          "query",
-          index
-        );
-        match value {
-          Either::Left(value) => {
-            reqres.request.query = update_query_map(index, name, reqres, &value);
-          }
-          Either::Right(values) => if index == 0 {
-            reqres.request.query = reqres.request.query.clone().map(|mut q| {
-              if q.contains_key(name) {
-                let vec = q.get_mut(name).unwrap();
-                vec.extend_from_slice(&values);
-              } else {
-                q.insert(name.to_string(), values.clone());
-              };
-              q
-            }).or_else(|| Some(hashmap! { name.to_string() => values }))
-          } else {
-            reqres.request.query = update_query_map(index, name, reqres, &values.first().cloned().unwrap_or_default());
+        if let Some(value) = value {
+          let value = from_integration_json_v2(
+            &mut reqres.request.matching_rules,
+            &mut reqres.request.generators,
+            value,
+            path,
+            "query",
+            index
+          );
+          match value {
+            Either::Left(value) => {
+              reqres.request.query = update_query_map(index, name, reqres, Some(value));
+            }
+            Either::Right(values) => if index == 0 {
+              reqres.request.query = reqres.request.query.clone().map(|mut q| {
+                let values = values.iter().map(|v| Some(v.clone())).collect_vec();
+                if q.contains_key(name) {
+                  let vec = q.get_mut(name).unwrap();
+                  vec.extend_from_slice(&values);
+                } else {
+                  q.insert(name.to_string(), values);
+                };
+                q
+              }).or_else(|| Some(hashmap! {
+                name.to_string() => values.iter().map(|v| Some(v.clone())).collect_vec()
+              }))
+            } else {
+              reqres.request.query = update_query_map(index, name, reqres, values.first().cloned());
+            }
           }
+        } else {
+          reqres.request.query = update_query_map(index, name, reqres, None);
         }
         !mock_server_started
       } else {
@@ -898,25 +909,29 @@ pub extern fn pactffi_with_query_parameter_v2(
   }
 }
 
-fn update_query_map(index: size_t, name: &str, reqres: &mut SynchronousHttp, value: &String) -> Option<HashMap<String, Vec<String>>> {
+fn update_query_map(
+  index: size_t,
+  name: &str,
+  reqres: &mut SynchronousHttp,
+  value: Option<String>
+) -> Option<HashMap<String, Vec<Option<String>>>> {
   reqres.request.query.clone().map(|mut q| {
-    if q.contains_key(name) {
-      let values = q.get_mut(name).unwrap();
-      if index >= values.len() {
-        values.resize_with(index + 1, Default::default);
+    if let Some(entry) = q.get_mut(name) {
+      if index >= entry.len() {
+        entry.resize_with(index + 1, Default::default);
       }
-      values[index] = value.clone();
+      entry[index] = value.clone();
     } else {
-      let mut values: Vec<String> = Vec::new();
+      let mut values: Vec<Option<String>> = Vec::new();
       values.resize_with(index + 1, Default::default);
       values[index] = value.clone();
       q.insert(name.to_string(), values);
     };
     q
   }).or_else(|| {
-    let mut values: Vec<String> = Vec::new();
+    let mut values: Vec<Option<String>> = Vec::new();
     values.resize_with(index + 1, Default::default);
-    values[index] = value.clone();
+    values[index] = value;
     Some(hashmap! { name.to_string() => values })
   })
 }
@@ -2866,7 +2881,7 @@ mod tests {
     pactffi_free_pact_handle(pact_handle);
 
     expect!(interaction.request.query.clone()).to(be_some().value(hashmap!{
-      "id".to_string() => vec!["100".to_string()]
+      "id".to_string() => vec![Some("100".to_string())]
     }));
     expect!(interaction.request.matching_rules.rules.get(&Category::QUERY).cloned().unwrap_or_default().is_empty()).to(be_true());
   }
@@ -2888,7 +2903,7 @@ mod tests {
     pactffi_free_pact_handle(pact_handle);
 
     expect!(interaction.request.query.clone()).to(be_some().value(hashmap!{
-      "id".to_string() => vec!["100".to_string()]
+      "id".to_string() => vec![Some("100".to_string())]
     }));
     expect!(&interaction.request.matching_rules).to(be_equal_to(&matchingrules! {
       "query" => { "$.id" => [ MatchingRule::Regex("\\d+".to_string()) ] }
@@ -2912,7 +2927,7 @@ mod tests {
     pactffi_free_pact_handle(pact_handle);
 
     expect!(interaction.request.query.clone()).to(be_some().value(hashmap!{
-      "id".to_string() => vec!["1".to_string(), "2".to_string()]
+      "id".to_string() => vec![Some("1".to_string()), Some("2".to_string())]
     }));
     expect!(interaction.request.matching_rules.rules.get(&Category::QUERY).cloned().unwrap_or_default().is_empty()).to(be_true());
   }
@@ -2936,7 +2951,7 @@ mod tests {
     pactffi_free_pact_handle(pact_handle);
 
     expect!(interaction.request.query.clone()).to(be_some().value(hashmap!{
-      "id".to_string() => vec!["100".to_string(), "abc".to_string()]
+      "id".to_string() => vec![Some("100".to_string()), Some("abc".to_string())]
     }));
     assert_eq!(&interaction.request.matching_rules, &matchingrules! {
       "query" => {
@@ -2964,7 +2979,7 @@ mod tests {
     pactffi_free_pact_handle(pact_handle);
 
     expect!(interaction.request.query.clone()).to(be_some().value(hashmap!{
-      "catId[]".to_string() => vec!["1".to_string()]
+      "catId[]".to_string() => vec![Some("1".to_string())]
     }));
     expect!(&interaction.request.matching_rules).to(be_equal_to(&matchingrules! {
       "query" => { "$['catId[]']" => [ MatchingRule::MinType(1) ] }
diff --git a/rust/pact_ffi/tests/tests.rs b/rust/pact_ffi/tests/tests.rs
index 018168496..7f7d25e48 100644
--- a/rust/pact_ffi/tests/tests.rs
+++ b/rust/pact_ffi/tests/tests.rs
@@ -140,7 +140,7 @@ fn create_query_parameter_with_multiple_values() {
   interaction.with_interaction(&|_, _, i| {
     let interaction = i.as_v4_http().unwrap();
     expect!(interaction.request.query.as_ref()).to(be_some().value(&hashmap!{
-      "q".to_string() => vec!["1".to_string(), "2".to_string(), "3".to_string()]
+      "q".to_string() => vec![Some("1".to_string()), Some("2".to_string()), Some("3".to_string())]
     }));
   });
 }
diff --git a/rust/pact_matching/src/form_urlencoded.rs b/rust/pact_matching/src/form_urlencoded.rs
index 57e4cd468..4867db44b 100644
--- a/rust/pact_matching/src/form_urlencoded.rs
+++ b/rust/pact_matching/src/form_urlencoded.rs
@@ -55,11 +55,11 @@ pub(crate) fn match_form_urlencoded(
         (Ok(e), Ok(a)) => {
           let expected_params = super::group_by(e, |(k, _)| k.clone())
             .iter()
-            .map(|(k, v)| (k.clone(), v.iter().map(|(_, v)| v.clone()).collect_vec()))
+            .map(|(k, v)| (k.clone(), v.iter().map(|(_, v)| Some(v.clone())).collect_vec()))
             .collect();
           let actual_params = super::group_by(a, |(k, _)| k.clone())
             .iter()
-            .map(|(k, v)| (k.clone(), v.iter().map(|(_, v)| v.clone()).collect_vec()))
+            .map(|(k, v)| (k.clone(), v.iter().map(|(_, v)| Some(v.clone())).collect_vec()))
             .collect();
           let result: Vec<_> = match_query_maps(expected_params, actual_params, context)
             .values().flat_map(|m| m.iter().map(|mismatch| {
@@ -220,7 +220,7 @@ mod tests {
       path: "$.a".to_string(),
       expected: Some("[\"b\"]".into()),
       actual: Some("".into()),
-      mismatch: "".to_string(),
+      mismatch: "Expected form post parameter 'a' but was missing".to_string()
     });
     assert_eq!(mismatches[0].description(), "$.a -> Expected form post parameter 'a' but was missing");
   }
diff --git a/rust/pact_matching/src/generator_tests.rs b/rust/pact_matching/src/generator_tests.rs
index 5ff22c245..411cc8816 100644
--- a/rust/pact_matching/src/generator_tests.rs
+++ b/rust/pact_matching/src/generator_tests.rs
@@ -75,8 +75,8 @@ async fn applies_header_generator_for_headers_to_the_copy_of_the_request() {
 #[tokio::test]
 async fn applies_query_generator_for_query_parameters_to_the_copy_of_the_request() {
   let request = HttpRequest { query: Some(hashmap!{
-      "A".to_string() => vec![ "a".to_string() ],
-      "B".to_string() => vec![ "b".to_string() ]
+      "A".to_string() => vec![ Some("a".to_string()) ],
+      "B".to_string() => vec![ Some("b".to_string()) ]
     }), generators: generators! {
       "QUERY" => {
         "A" => Generator::Uuid(None)
@@ -84,16 +84,16 @@ async fn applies_query_generator_for_query_parameters_to_the_copy_of_the_request
     }, .. HttpRequest::default()
   };
   let query = generate_request(&request, &GeneratorTestMode::Provider, &hashmap!{}).await.query.unwrap().clone();
-  let query_val = &query.get("A").unwrap()[0];
-  expect!(query_val).to_not(be_equal_to("a"));
+  let query_val = query.get("A").unwrap()[0].as_ref();
+  expect!(query_val.unwrap()).to_not(be_equal_to("a"));
 }
 
 #[test_log::test(tokio::test)]
 async fn applies_provider_state_generator_for_query_parameters_with_square_brackets() {
   let request = HttpRequest {
     query: Some(hashmap!{
-      "A".to_string() => vec![ "a".to_string() ],
-      "q[]".to_string() => vec![ "q1".to_string(), "q2".to_string() ]
+      "A".to_string() => vec![ Some("a".to_string()) ],
+      "q[]".to_string() => vec![ Some("q1".to_string()), Some("q2".to_string()) ]
     }),
     generators: generators! {
       "QUERY" => {
@@ -109,9 +109,9 @@ async fn applies_provider_state_generator_for_query_parameters_with_square_brack
   let result = generate_request(&request, &GeneratorTestMode::Provider, &context).await;
   let query = result.query.unwrap();
   let a_val = query.get("A").unwrap();
-  expect!(a_val).to(be_equal_to(&vec!["1234".to_string()]));
+  expect!(a_val).to(be_equal_to(&vec![Some("1234".to_string())]));
   let q_val = query.get("q[]").unwrap();
-  expect!(q_val).to(be_equal_to(&vec!["5678".to_string(), "5678".to_string()]));
+  expect!(q_val).to(be_equal_to(&vec![Some("5678".to_string()), Some("5678".to_string())]));
 }
 
 #[tokio::test]
diff --git a/rust/pact_matching/src/lib.rs b/rust/pact_matching/src/lib.rs
index e657f3e82..8fc0914f3 100644
--- a/rust/pact_matching/src/lib.rs
+++ b/rust/pact_matching/src/lib.rs
@@ -789,8 +789,8 @@ impl CommonMismatch {
   pub fn to_query_mismatch(&self) -> Mismatch {
     Mismatch::QueryMismatch {
       parameter: self.path.clone(),
-      expected: self.expected.clone().into(),
-      actual: self.actual.clone().into(),
+      expected: self.expected.clone(),
+      actual: self.actual.clone(),
       mismatch: self.description.clone()
     }
   }
@@ -1426,24 +1426,26 @@ pub fn match_path(expected: &str, actual: &str, context: &(dyn MatchingContext +
 
 /// Matches the actual query parameters to the expected ones.
 pub fn match_query(
-  expected: Option<HashMap<String, Vec<String>>>,
-  actual: Option<HashMap<String, Vec<String>>>,
+  expected: Option<HashMap<String, Vec<Option<String>>>>,
+  actual: Option<HashMap<String, Vec<Option<String>>>>,
   context: &(dyn MatchingContext + Send + Sync)
 ) -> HashMap<String, Vec<Mismatch>> {
   match (actual, expected) {
     (Some(aqm), Some(eqm)) => match_query_maps(eqm, aqm, context),
     (Some(aqm), None) => aqm.iter().map(|(key, value)| {
+      let actual_value = value.iter().map(|v| v.clone().unwrap_or_default()).collect_vec();
       (key.clone(), vec![Mismatch::QueryMismatch {
         parameter: key.clone(),
         expected: "".to_string(),
-        actual: format!("{:?}", value),
+        actual: format!("{:?}", actual_value),
         mismatch: format!("Unexpected query parameter '{}' received", key)
       }])
     }).collect(),
     (None, Some(eqm)) => eqm.iter().map(|(key, value)| {
+      let expected_value = value.iter().map(|v| v.clone().unwrap_or_default()).collect_vec();
       (key.clone(), vec![Mismatch::QueryMismatch {
         parameter: key.clone(),
-        expected: format!("{:?}", value),
+        expected: format!("{:?}", expected_value),
         actual: "".to_string(),
         mismatch: format!("Expected query parameter '{}' but was missing", key)
       }])
@@ -2103,22 +2105,19 @@ pub async fn generate_request(request: &HttpRequest, mode: &GeneratorTestMode, c
           if let Some(parameter) = parameters.get_mut(param) {
             let mut generated = parameter.clone();
             for (index, val) in parameter.iter().enumerate() {
-              if let Ok(v) = generator.generate_value(val, context, &DefaultVariantMatcher.boxed()) {
-                generated[index] = v;
+              let value = val.clone().unwrap_or_default();
+              if let Ok(v) = generator.generate_value(&value, context, &DefaultVariantMatcher.boxed()) {
+                generated[index] = Some(v);
               }
             }
             *parameter = generated;
-          } else {
-            if let Ok(v) = generator.generate_value(&"".to_string(), context, &DefaultVariantMatcher.boxed()) {
-              parameters.insert(param.to_string(), vec![ v.to_string() ]);
-            }
-          }
-        } else {
-          if let Ok(v) = generator.generate_value(&"".to_string(), context, &DefaultVariantMatcher.boxed()) {
-            request.query = Some(hashmap!{
-              param.to_string() => vec![ v.to_string() ]
-            })
+          } else if let Ok(v) = generator.generate_value(&"".to_string(), context, &DefaultVariantMatcher.boxed()) {
+            parameters.insert(param.to_string(), vec![ Some(v.to_string()) ]);
           }
+        } else if let Ok(v) = generator.generate_value(&"".to_string(), context, &DefaultVariantMatcher.boxed()) {
+          request.query = Some(hashmap!{
+            param.to_string() => vec![ Some(v.to_string()) ]
+          })
         }
       }
     });
diff --git a/rust/pact_matching/src/query.rs b/rust/pact_matching/src/query.rs
index 3b7f88687..ece09faff 100644
--- a/rust/pact_matching/src/query.rs
+++ b/rust/pact_matching/src/query.rs
@@ -13,22 +13,24 @@ use crate::matchingrules::compare_lists_with_matchingrules;
 
 /// Match the query parameters as Maps
 pub(crate) fn match_query_maps(
-  expected: HashMap<String, Vec<String>>,
-  actual: HashMap<String, Vec<String>>,
+  expected: HashMap<String, Vec<Option<String>>>,
+  actual: HashMap<String, Vec<Option<String>>>,
   context: &dyn MatchingContext
 ) -> HashMap<String, Vec<Mismatch>> {
   let mut result: HashMap<String, Vec<Mismatch>> = hashmap!{};
   for (key, value) in &expected {
+    let expected_value = value.iter().map(|v| v.clone().unwrap_or_default()).collect_vec();
     match actual.get(key) {
       Some(actual_value) => {
-        let mismatches: Result<(), Vec<super::Mismatch>> = match_query_values(key, value, actual_value, context)
+        let actual_value = actual_value.iter().map(|v| v.clone().unwrap_or_default()).collect_vec();
+        let mismatches: Result<(), Vec<super::Mismatch>> = match_query_values(key, &expected_value, &actual_value, context)
           .map_err(|mismatches| mismatches.iter().map(|mismatch| mismatch.to_query_mismatch()).collect());
         let v = result.entry(key.clone()).or_default();
         v.extend(mismatches.err().unwrap_or_default());
       },
       None => result.entry(key.clone()).or_default().push(Mismatch::QueryMismatch {
         parameter: key.clone(),
-        expected: format!("{:?}", value),
+        expected: format!("{:?}", expected_value),
         actual: "".to_string(),
         mismatch: format!("Expected query parameter '{}' but was missing", key)
       })
@@ -40,7 +42,7 @@ pub(crate) fn match_query_maps(
       None => result.entry(key.clone()).or_default().push(Mismatch::QueryMismatch {
         parameter: key.clone(),
         expected: "".to_string(),
-        actual: format!("{:?}", value),
+        actual: format!("{:?}", value.iter().map(|v| v.clone().unwrap_or_default()).collect_vec()),
         mismatch: format!("Unexpected query parameter '{}' received", key)
       })
     }
diff --git a/rust/pact_matching/src/tests.rs b/rust/pact_matching/src/tests.rs
index c4e27e6f2..a881cfa6c 100644
--- a/rust/pact_matching/src/tests.rs
+++ b/rust/pact_matching/src/tests.rs
@@ -1,6 +1,7 @@
 use std::collections::HashMap;
 
 use expectest::prelude::*;
+use pretty_assertions::assert_eq;
 
 use pact_models::{matchingrules, matchingrules_list};
 use pact_models::matchingrules::expressions::{MatchingRuleDefinition, ValueType};
@@ -69,8 +70,8 @@ fn match_query_returns_nothing_if_there_are_no_query_strings() {
 
 #[test]
 fn match_query_applies_matching_rules_when_param_has_an_underscore() {
-  let expected = hashmap! { "user_id".to_string() => vec!["1".to_string()] };
-  let actual = hashmap! { "user_id".to_string() => vec!["2".to_string()] };
+  let expected = hashmap! { "user_id".to_string() => vec![Some("1".to_string())] };
+  let actual = hashmap! { "user_id".to_string() => vec![Some("2".to_string())] };
   let rules = matchingrules! {
     "query" => { "user_id" => [ MatchingRule::Regex("^[0-9]+$".to_string()) ] }
   };
@@ -86,7 +87,7 @@ fn match_query_applies_matching_rules_when_param_has_an_underscore() {
 fn match_query_returns_a_mismatch_if_there_is_no_expected_query_string() {
   let expected = None;
   let mut query_map = HashMap::new();
-  query_map.insert("a".to_string(), vec!["b".to_string()]);
+  query_map.insert("a".to_string(), vec![Some("b".to_string())]);
   let actual = Some(query_map);
   let result = match_query(expected, actual, &CoreMatchingContext::default());
   let mismatches: Vec<Mismatch> = result.values().flatten().cloned().collect();
@@ -102,7 +103,7 @@ fn match_query_returns_a_mismatch_if_there_is_no_expected_query_string() {
 #[test]
 fn match_query_returns_a_mismatch_if_there_is_no_actual_query_string() {
   let mut query_map = HashMap::new();
-  query_map.insert("a".to_string(), vec!["b".to_string()]);
+  query_map.insert("a".to_string(), vec![Some("b".to_string())]);
   let expected = Some(query_map);
   let actual = None;
   let result = match_query(expected, actual, &CoreMatchingContext::default());
@@ -119,11 +120,11 @@ fn match_query_returns_a_mismatch_if_there_is_no_actual_query_string() {
 #[test]
 fn match_query_returns_a_mismatch_if_there_is_an_actual_query_parameter_that_is_not_expected() {
   let mut query_map = HashMap::new();
-  query_map.insert("a".to_string(), vec!["b".to_string()]);
+  query_map.insert("a".to_string(), vec![Some("b".to_string())]);
   let expected = Some(query_map);
   query_map = HashMap::new();
-  query_map.insert("a".to_string(), vec!["b".to_string()]);
-  query_map.insert("c".to_string(), vec!["d".to_string()]);
+  query_map.insert("a".to_string(), vec![Some("b".to_string())]);
+  query_map.insert("c".to_string(), vec![Some("d".to_string())]);
   let actual = Some(query_map);
   let result = match_query(expected, actual, &CoreMatchingContext::default());
   let mismatches: Vec<Mismatch> = result.values().flatten().cloned().collect();
@@ -139,11 +140,11 @@ fn match_query_returns_a_mismatch_if_there_is_an_actual_query_parameter_that_is_
 #[test]
 fn match_query_returns_a_mismatch_if_there_is_an_expected_query_parameter_that_is_not_received() {
   let mut query_map = HashMap::new();
-  query_map.insert("a".to_string(), vec!["b".to_string()]);
-  query_map.insert("c".to_string(), vec!["d".to_string()]);
+  query_map.insert("a".to_string(), vec![Some("b".to_string())]);
+  query_map.insert("c".to_string(), vec![Some("d".to_string())]);
   let expected = Some(query_map);
   query_map = HashMap::new();
-  query_map.insert("a".to_string(), vec!["b".to_string()]);
+  query_map.insert("a".to_string(), vec![Some("b".to_string())]);
   let actual = Some(query_map);
   let result = match_query(expected, actual, &CoreMatchingContext::default());
   let mismatches: Vec<Mismatch> = result.values().flatten().cloned().collect();
@@ -159,12 +160,12 @@ fn match_query_returns_a_mismatch_if_there_is_an_expected_query_parameter_that_i
 #[test]
 fn match_query_returns_a_mismatch_if_there_is_an_empty_expected_query_parameter_and_a_non_empty_actual() {
   let mut query_map = HashMap::new();
-  query_map.insert("a".to_string(), vec!["b".to_string()]);
+  query_map.insert("a".to_string(), vec![Some("b".to_string())]);
   query_map.insert("c".to_string(), vec![]);
   let expected = Some(query_map);
   query_map = HashMap::new();
-  query_map.insert("a".to_string(), vec!["b".to_string()]);
-  query_map.insert("c".to_string(), vec!["d".to_string()]);
+  query_map.insert("a".to_string(), vec![Some("b".to_string())]);
+  query_map.insert("c".to_string(), vec![Some("d".to_string())]);
   let actual = Some(query_map);
   let result = match_query(expected, actual, &CoreMatchingContext::default());
   let mismatches: Vec<Mismatch> = result.values().flatten().cloned().collect();
@@ -180,12 +181,12 @@ fn match_query_returns_a_mismatch_if_there_is_an_empty_expected_query_parameter_
 #[test]
 fn match_query_returns_a_mismatch_if_the_query_values_have_different_lengths() {
   let mut query_map = HashMap::new();
-  query_map.insert("a".to_string(), vec!["b".to_string()]);
-  query_map.insert("c".to_string(), vec!["d".to_string(), "e".to_string()]);
+  query_map.insert("a".to_string(), vec![Some("b".to_string())]);
+  query_map.insert("c".to_string(), vec![Some("d".to_string()), Some("e".to_string())]);
   let expected = Some(query_map);
   query_map = HashMap::new();
-  query_map.insert("a".to_string(), vec!["b".to_string()]);
-  query_map.insert("c".to_string(), vec!["d".to_string()]);
+  query_map.insert("a".to_string(), vec![Some("b".to_string())]);
+  query_map.insert("c".to_string(), vec![Some("d".to_string())]);
   let actual = Some(query_map);
   let result = match_query(expected, actual, &CoreMatchingContext::default());
   let mismatches: Vec<Mismatch> = result.values().flatten().cloned().collect();
@@ -207,10 +208,10 @@ fn match_query_returns_a_mismatch_if_the_query_values_have_different_lengths() {
 #[test]
 fn match_query_returns_a_mismatch_if_the_values_are_not_the_same() {
   let mut query_map = HashMap::new();
-  query_map.insert("a".to_string(), vec!["b".to_string()]);
+  query_map.insert("a".to_string(), vec![Some("b".to_string())]);
   let expected = Some(query_map);
   query_map = HashMap::new();
-  query_map.insert("a".to_string(), vec!["c".to_string()]);
+  query_map.insert("a".to_string(), vec![Some("c".to_string())]);
   let actual = Some(query_map);
   let result = match_query(expected, actual, &CoreMatchingContext::default());
   let mismatches: Vec<Mismatch> = result.values().flatten().cloned().collect();
@@ -225,12 +226,12 @@ fn match_query_returns_a_mismatch_if_the_values_are_not_the_same() {
 
 #[test]
 fn match_query_with_min_type_matching_rules() {
-  let expected = hashmap! { "id".to_string() => vec!["1".to_string(), "2".to_string()] };
+  let expected = hashmap! { "id".to_string() => vec![Some("1".to_string()), Some("2".to_string())] };
   let actual = hashmap! { "id".to_string() => vec![
-    "1".to_string(),
-    "2".to_string(),
-    "3".to_string(),
-    "4".to_string()
+    Some("1".to_string()),
+    Some("2".to_string()),
+    Some("3".to_string()),
+    Some("4".to_string())
   ]};
   let rules = matchingrules! {
     "query" => { "id" => [ MatchingRule::MinType(2) ] }
@@ -246,12 +247,12 @@ fn match_query_with_min_type_matching_rules() {
 #[test]
 fn match_query_with_min_type_matching_rules_fails() {
   let expected = hashmap! { "id".to_string() => vec![
-    "1".to_string(),
-    "2".to_string(),
-    "3".to_string(),
-    "4".to_string()
+    Some("1".to_string()),
+    Some("2".to_string()),
+    Some("3".to_string()),
+    Some("4".to_string())
   ]};
-  let actual = hashmap! { "id".to_string() => vec!["1".to_string()] };
+  let actual = hashmap! { "id".to_string() => vec![Some("1".to_string())] };
   let rules = matchingrules! {
     "query" => { "id" => [ MatchingRule::MinType(2) ] }
   };
@@ -283,10 +284,10 @@ fn match_query_returns_no_mismatch_if_the_values_are_not_the_same_but_match_by_a
     }.rules_for_category("query").unwrap_or_default(), &hashmap!{}
   );
   let mut query_map = HashMap::new();
-  query_map.insert("a".to_string(), vec!["b".to_string()]);
+  query_map.insert("a".to_string(), vec![Some("b".to_string())]);
   let expected = Some(query_map);
   query_map = HashMap::new();
-  query_map.insert("a".to_string(), vec!["c".to_string()]);
+  query_map.insert("a".to_string(), vec![Some("c".to_string())]);
   let actual = Some(query_map);
   let result = match_query(expected, actual, &context);
   expect!(result.get("a").unwrap().iter()).to(be_empty());
@@ -303,10 +304,10 @@ fn match_query_returns_a_mismatch_if_the_values_do_not_match_by_a_matcher() {
     }.rules_for_category("query").unwrap_or_default(), &hashmap!{}
   );
   let mut query_map = HashMap::new();
-  query_map.insert("a".to_string(), vec!["b".to_string()]);
+  query_map.insert("a".to_string(), vec![Some("b".to_string())]);
   let expected = Some(query_map);
   query_map = HashMap::new();
-  query_map.insert("a".to_string(), vec!["b".to_string()]);
+  query_map.insert("a".to_string(), vec![Some("b".to_string())]);
   let actual = Some(query_map);
   let result = match_query(expected, actual, &context);
   expect!(result.iter()).to_not(be_empty());
@@ -340,10 +341,10 @@ fn match_query_with_query_parameters_with_brackets() {
   );
 
   let expected = hashmap!{
-    "Q[]".to_string() => vec!["1".to_string(), "2".to_string()]
+    "Q[]".to_string() => vec![Some("1".to_string()), Some("2".to_string())]
   };
   let actual = hashmap!{
-    "Q[]".to_string() => vec!["100".to_string(), "2000".to_string(), "999".to_string()]
+    "Q[]".to_string() => vec![Some("100".to_string()), Some("2000".to_string()), Some("999".to_string())]
   };
   let result = match_query(Some(expected), Some(actual), &context);
   expect!(result.get("Q[]").unwrap().iter()).to(be_empty());
@@ -352,12 +353,12 @@ fn match_query_with_query_parameters_with_brackets() {
 
 #[test]
 fn match_query_with_array_contains_matching_rules() {
-  let expected = hashmap! { "id".to_string() => vec!["1".to_string(), "3".to_string()] };
+  let expected = hashmap! { "id".to_string() => vec![Some("1".to_string()), Some("3".to_string())] };
   let actual = hashmap! { "id".to_string() => vec![
-    "1".to_string(),
-    "2".to_string(),
-    "3".to_string(),
-    "4".to_string()
+    Some("1".to_string()),
+    Some("2".to_string()),
+    Some("3".to_string()),
+    Some("4".to_string())
   ]};
   let rules = matchingrules! {
     "query" => { "id" => [ MatchingRule::ArrayContains(vec![]) ] }
@@ -374,8 +375,8 @@ fn match_query_with_array_contains_matching_rules() {
 
 #[test]
 fn match_query_with_array_contains_matching_rules_fails() {
-  let expected = hashmap! { "id".to_string() => vec!["1".to_string(), "3".to_string()] };
-  let actual = hashmap! { "id".to_string() => vec!["2".to_string(), "3".to_string(), "4".to_string()] };
+  let expected = hashmap! { "id".to_string() => vec![Some("1".to_string()), Some("3".to_string())] };
+  let actual = hashmap! { "id".to_string() => vec![Some("2".to_string()), Some("3".to_string()), Some("4".to_string())] };
   let rules = matchingrules! {
     "query" => { "id" => [ MatchingRule::ArrayContains(vec![]) ] }
   };
@@ -398,8 +399,8 @@ fn match_query_with_array_contains_matching_rules_fails() {
 
 #[test]
 fn match_query_with_each_value_matching_rules() {
-  let expected = hashmap! { "id".to_string() => vec!["1".to_string(), "2".to_string()] };
-  let actual = hashmap! { "id".to_string() => vec!["3".to_string(), "4".to_string(), "567".to_string()] };
+  let expected = hashmap! { "id".to_string() => vec![Some("1".to_string()), Some("2".to_string())] };
+  let actual = hashmap! { "id".to_string() => vec![Some("3".to_string()), Some("4".to_string()), Some("567".to_string())] };
   let rules = matchingrules! {
     "query" => { "id" => [ MatchingRule::EachValue(MatchingRuleDefinition::new("100".to_string(), ValueType::String,
       MatchingRule::Regex("\\d+".to_string()), None)) ] }
@@ -416,8 +417,8 @@ fn match_query_with_each_value_matching_rules() {
 
 #[test]
 fn match_query_with_each_value_matching_rules_fails() {
-  let expected = hashmap! { "id".to_string() => vec!["1".to_string(), "2".to_string()] };
-  let actual = hashmap! { "id".to_string() => vec!["3".to_string(), "abc123".to_string(), "test".to_string()] };
+  let expected = hashmap! { "id".to_string() => vec![Some("1".to_string()), Some("2".to_string())] };
+  let actual = hashmap! { "id".to_string() => vec![Some("3".to_string()), Some("abc123".to_string()), Some("test".to_string())] };
   let rules = matchingrules! {
     "query" => { "id" => [ MatchingRule::EachValue(MatchingRuleDefinition::new("100".to_string(), ValueType::String,
       MatchingRule::Regex("\\d+".to_string()), None)) ] }
diff --git a/rust/pact_mock_server/src/hyper_server.rs b/rust/pact_mock_server/src/hyper_server.rs
index 57e758f26..a64e38977 100644
--- a/rust/pact_mock_server/src/hyper_server.rs
+++ b/rust/pact_mock_server/src/hyper_server.rs
@@ -47,7 +47,7 @@ fn extract_path(uri: &hyper::Uri) -> String {
         .into()
 }
 
-fn extract_query_string(uri: &hyper::Uri) -> Option<HashMap<String, Vec<String>>> {
+fn extract_query_string(uri: &hyper::Uri) -> Option<HashMap<String, Vec<Option<String>>>> {
   debug!("Extracting query from uri {:?}", uri);
   uri.path_and_query()
     .and_then(|path_and_query| {
diff --git a/rust/pact_mock_server/src/tests.rs b/rust/pact_mock_server/src/tests.rs
index a567c67b2..f8f79961f 100644
--- a/rust/pact_mock_server/src/tests.rs
+++ b/rust/pact_mock_server/src/tests.rs
@@ -78,7 +78,7 @@ async fn match_request_returns_a_match_for_multiple_requests() {
 #[tokio::test]
 async fn match_request_returns_a_mismatch_for_incorrect_request() {
     let request = HttpRequest::default();
-    let expected_request = HttpRequest { query: Some(hashmap!{ "QueryA".to_string() => vec!["Value A".to_string()] }),
+    let expected_request = HttpRequest { query: Some(hashmap!{ "QueryA".to_string() => vec![Some("Value A".to_string())] }),
         .. HttpRequest::default() };
     let interaction = SynchronousHttp {
       request: expected_request,
@@ -114,11 +114,11 @@ async fn match_request_returns_the_most_appropriate_mismatch_for_multiple_reques
     let request = HttpRequest { method: "GET".to_string(), path: "/".to_string(), body: OptionalBody::Present("This is a body".into(), None, None),
       .. HttpRequest::default() };
     let request2 = HttpRequest { method: "GET".to_string(), path: "/".to_string(), query: Some(hashmap!{
-        "QueryA".to_string() => vec!["Value A".to_string()]
+        "QueryA".to_string() => vec![Some("Value A".to_string())]
         }), body: OptionalBody::Present("This is a body".into(), None, None),
       .. HttpRequest::default() };
     let request3 = HttpRequest { method: "GET".to_string(), path: "/".to_string(), query: Some(hashmap!{
-        "QueryA".to_string() => vec!["Value A".to_string()]
+        "QueryA".to_string() => vec![Some("Value A".to_string())]
         }), body: OptionalBody::Missing, .. HttpRequest::default() };
     let interaction = SynchronousHttp { description: "test".to_string(), request: request.clone(), .. SynchronousHttp::default() };
     let interaction2 = SynchronousHttp { description: "test2".to_string(), request: request2.clone(), .. SynchronousHttp::default() };
diff --git a/rust/pact_models/Cargo.toml b/rust/pact_models/Cargo.toml
index b7b6c9d2d..3b870720a 100644
--- a/rust/pact_models/Cargo.toml
+++ b/rust/pact_models/Cargo.toml
@@ -58,10 +58,10 @@ uuid = { version = "1.3.3", features = ["v4"] }
 
 [dev-dependencies]
 expectest = "0.12.0"
-env_logger = "0.10.0"
+env_logger = "0.11.3"
 hamcrest2 = "0.3.0"
 pretty_assertions = "1.3.0"
-rstest = "0.17.0"
+rstest = "0.19.0"
 speculate = "0.1.2"
 test-log = { version = "0.2.11", features = ["trace"] }
 tracing-subscriber = { version = "0.3.16", features = ["env-filter", "tracing-log", "fmt"] }
diff --git a/rust/pact_models/src/json_utils.rs b/rust/pact_models/src/json_utils.rs
index 42c42809d..ddebc29c9 100644
--- a/rust/pact_models/src/json_utils.rs
+++ b/rust/pact_models/src/json_utils.rs
@@ -138,6 +138,7 @@ pub fn headers_to_json(headers: &HashMap<String, Vec<String>>) -> Value {
 
 #[derive(Deserialize)]
 #[serde(untagged)]
+#[allow(dead_code)]
 enum JsonParsable {
   JsonStringValue(String),
   KeyValue(HashMap<String, Value>)
diff --git a/rust/pact_models/src/pact.rs b/rust/pact_models/src/pact.rs
index 5f7ea9a41..0ad19e1bc 100644
--- a/rust/pact_models/src/pact.rs
+++ b/rust/pact_models/src/pact.rs
@@ -591,7 +591,10 @@ mod tests {
     expect!(interaction.request).to(be_equal_to(Request {
       method: "GET".to_string(),
       path: "/mallory".to_string(),
-      query: Some(hashmap!{ "name".to_string() => vec!["ron".to_string()], "status".to_string() => vec!["good".to_string()] }),
+      query: Some(hashmap!{
+        "name".to_string() => vec![Some("ron".to_string())],
+        "status".to_string() => vec![Some("good".to_string())]
+      }),
       headers: None,
       body: OptionalBody::Missing,
       .. Request::default()
@@ -666,7 +669,10 @@ mod tests {
     expect!(interaction.request).to(be_equal_to(Request {
       method: "GET".to_string(),
       path: "/".to_string(),
-      query: Some(hashmap!{ "q".to_string() => vec!["p".to_string(), "p2".to_string()], "r".to_string() => vec!["s".to_string()] }),
+      query: Some(hashmap!{
+        "q".to_string() => vec![Some("p".to_string()), Some("p2".to_string())],
+        "r".to_string() => vec![Some("s".to_string())]
+      }),
       headers: Some(hashmap!{ "testreqheader".to_string() => vec!["testreqheadervalue".to_string()] }),
       body: "{\"test\":true}".into(),
       .. Request::default()
@@ -742,7 +748,10 @@ mod tests {
     expect!(interaction.request).to(be_equal_to(Request {
       method: "GET".to_string(),
       path: "/".to_string(),
-      query: Some(hashmap!{ "q".to_string() => vec!["p".to_string(), "p2".to_string()], "r".to_string() => vec!["s".to_string()] }),
+      query: Some(hashmap!{
+        "q".to_string() => vec![Some("p".to_string()), Some("p2".to_string())],
+        "r".to_string() => vec![Some("s".to_string())]
+      }),
       headers: Some(hashmap!{ "testreqheader".to_string() => vec!["testreqheadervalue".to_string()] }),
       body: OptionalBody::Present("{\"test\":true}".into(), None, None),
       .. Request::default()
@@ -807,8 +816,10 @@ mod tests {
     expect!(interaction.request).to(be_equal_to(Request {
       method: "GET".to_string(),
       path: "/".to_string(),
-      query: Some(hashmap!{ "datetime".to_string() => vec!["2011-12-03T10:15:30+01:00".to_string()],
-            "description".to_string() => vec!["hello world!".to_string()] }),
+      query: Some(hashmap!{
+        "datetime".to_string() => vec![Some("2011-12-03T10:15:30+01:00".to_string())],
+        "description".to_string() => vec![Some("hello world!".to_string())]
+      }),
       headers: Some(hashmap!{ "testreqheader".to_string() => vec!["testreqheadervalue".to_string()] }),
       body: OptionalBody::Present("{\"test\":true}".into(), None, None),
       .. Request::default()
@@ -1529,9 +1540,9 @@ mod tests {
           provider_states: vec![ProviderState { name: "Good state to be in".to_string(), params: hashmap!{} }],
           request: Request {
             query: Some(hashmap!{
-                        "a".to_string() => vec!["1".to_string(), "2".to_string(), "3".to_string()],
-                        "b".to_string() => vec!["bill".to_string(), "bob".to_string()],
-                    }),
+                "a".to_string() => vec![Some("1".to_string()), Some("2".to_string()), Some("3".to_string())],
+                "b".to_string() => vec![Some("bill".to_string()), Some("bob".to_string())]
+            }),
             .. Request::default()
           },
           .. RequestResponseInteraction::default()
diff --git a/rust/pact_models/src/query_strings.rs b/rust/pact_models/src/query_strings.rs
index b61302203..c409f1201 100644
--- a/rust/pact_models/src/query_strings.rs
+++ b/rust/pact_models/src/query_strings.rs
@@ -89,16 +89,14 @@ pub fn encode_query(query: &str) -> String {
 /// Parses a query string into an optional map. The query parameter name will be mapped to
 /// a list of values. Where the query parameter is repeated, the order of the values will be
 /// preserved.
-pub fn parse_query_string(query: &str) -> Option<HashMap<String, Vec<String>>> {
+pub fn parse_query_string(query: &str) -> Option<HashMap<String, Vec<Option<String>>>> {
   if !query.is_empty() {
     Some(query.split('&').map(|kv| {
       trace!("kv = '{}'", kv);
       if kv.is_empty() {
         vec![]
-      } else if kv.contains('=') {
-        kv.splitn(2, '=').collect::<Vec<&str>>()
       } else {
-        vec![kv]
+        kv.splitn(2, '=').collect::<Vec<&str>>()
       }
     }).fold(HashMap::new(), |mut map, name_value| {
       trace!("name_value = '{:?}'", name_value);
@@ -106,11 +104,11 @@ pub fn parse_query_string(query: &str) -> Option<HashMap<String, Vec<String>>> {
         let name = decode_query(name_value[0])
           .unwrap_or_else(|_| name_value[0].to_owned());
         let value = if name_value.len() > 1 {
-          decode_query(name_value[1]).unwrap_or_else(|_| name_value[1].to_owned())
+          Some(decode_query(name_value[1]).unwrap_or_else(|_| name_value[1].to_owned()))
         } else {
-          String::default()
+          None
         };
-        trace!("decoded: '{}' => '{}'", name, value);
+        trace!("decoded: '{}' => {:?}", name, value);
         map.entry(name).or_insert_with(|| vec![]).push(value);
       }
       map
@@ -121,21 +119,24 @@ pub fn parse_query_string(query: &str) -> Option<HashMap<String, Vec<String>>> {
 }
 
 /// Converts a query string map into a query string
-pub fn build_query_string(query: HashMap<String, Vec<String>>) -> String {
+pub fn build_query_string(query: HashMap<String, Vec<Option<String>>>) -> String {
   query.into_iter()
     .sorted_by(|a, b| Ord::cmp(&a.0, &b.0))
     .flat_map(|kv| {
       kv.1.iter()
-        .map(|v| format!("{}={}", kv.0, encode_query(v)))
+        .map(|v| match v {
+          None => kv.0.clone(),
+          Some(s) => format!("{}={}", kv.0, encode_query(s))
+        })
         .collect_vec()
     })
     .join("&")
 }
 
 /// Parses a V2 query string from a JSON struct
-pub fn query_from_json(query_json: &Value, spec_version: &PactSpecification) -> Option<HashMap<String, Vec<String>>> {
+pub fn query_from_json(query_json: &Value, spec_version: &PactSpecification) -> Option<HashMap<String, Vec<Option<String>>>> {
   match query_json {
-    &Value::String(ref s) => parse_query_string(s),
+    Value::String(s) => parse_query_string(s),
     _ => {
       warn!("Only string versions of request query strings are supported with specification version {}, ignoring.",
         spec_version.to_string());
@@ -145,18 +146,22 @@ pub fn query_from_json(query_json: &Value, spec_version: &PactSpecification) ->
 }
 
 /// Parses a V3 query string from a JSON struct
-pub fn v3_query_from_json(query_json: &Value, spec_version: &PactSpecification) -> Option<HashMap<String, Vec<String>>> {
+pub fn v3_query_from_json(
+  query_json: &Value,
+  spec_version: &PactSpecification
+) -> Option<HashMap<String, Vec<Option<String>>>> {
   match query_json {
-    &Value::String(ref s) => parse_query_string(s),
-    &Value::Object(ref map) => Some(map.iter().map(|(k, v)| {
+    Value::String(s) => parse_query_string(s),
+    Value::Object(map) => Some(map.iter().map(|(k, v)| {
       (k.clone(), match v {
-        &Value::String(ref s) => vec![s.clone()],
-        &Value::Array(ref array) => array.iter().map(|item| match item {
-          &Value::String(ref s) => s.clone(),
-          _ => v.to_string()
+        Value::String(s) => vec![Some(s.clone())],
+        Value::Array(array) => array.iter().map(|item| match item {
+          Value::String(s) => Some(s.clone()),
+          Value::Null => None,
+          _ => Some(v.to_string())
         }).collect(),
         _ => {
-          warn!("Query paramter value '{}' is not valid, ignoring", v);
+          warn!("Query parameter value '{}' is not valid, ignoring", v);
           vec![]
         }
       })
@@ -170,13 +175,16 @@ pub fn v3_query_from_json(query_json: &Value, spec_version: &PactSpecification)
 }
 
 /// Converts a query string structure into a JSON struct
-pub fn query_to_json(query: HashMap<String, Vec<String>>, spec_version: &PactSpecification) -> Value {
+pub fn query_to_json(query: HashMap<String, Vec<Option<String>>>, spec_version: &PactSpecification) -> Value {
   match spec_version {
     PactSpecification::V3 | PactSpecification::V4 => Value::Object(query
       .iter()
       .sorted_by(|(a, _), (b, _)| Ord::cmp(a, b))
       .map(|(k, v)| {
-        (k.clone(), Value::Array(v.iter().map(|q| Value::String(q.clone())).collect()))
+        (k.clone(), Value::Array(v.iter().map(|q| match q {
+          None => Value::Null,
+          Some(s) => Value::String(s.clone())
+        }).collect()))
       })
       .collect()),
     _ => Value::String(build_query_string(query))
@@ -189,6 +197,8 @@ mod tests {
 
   use expectest::prelude::*;
   use maplit::hashmap;
+  use pretty_assertions::assert_eq;
+  use rstest::rstest;
 
   use crate::query_strings::parse_query_string;
 
@@ -196,8 +206,8 @@ mod tests {
   fn parse_query_string_test() {
     let query = "a=b&c=d".to_string();
     let expected = hashmap!{
-    "a".to_string() => vec!["b".to_string()],
-    "c".to_string() => vec!["d".to_string()]
+    "a".to_string() => vec![Some("b".to_string())],
+    "c".to_string() => vec![Some("d".to_string())]
   };
     let result = parse_query_string(&query);
     expect!(result).to(be_some().value(expected));
@@ -215,8 +225,8 @@ mod tests {
   fn parse_query_string_handles_missing_values() {
     let query = "a=&c=d".to_string();
     let mut expected = HashMap::new();
-    expected.insert("a".to_string(), vec!["".to_string()]);
-    expected.insert("c".to_string(), vec!["d".to_string()]);
+    expected.insert("a".to_string(), vec![Some("".to_string())]);
+    expected.insert("c".to_string(), vec![Some("d".to_string())]);
     let result = parse_query_string(&query);
     assert_eq!(result, Some(expected));
   }
@@ -225,8 +235,8 @@ mod tests {
   fn parse_query_string_handles_equals_in_values() {
     let query = "a=b&c=d=e=f".to_string();
     let mut expected = HashMap::new();
-    expected.insert("a".to_string(), vec!["b".to_string()]);
-    expected.insert("c".to_string(), vec!["d=e=f".to_string()]);
+    expected.insert("a".to_string(), vec![Some("b".to_string())]);
+    expected.insert("c".to_string(), vec![Some("d=e=f".to_string())]);
     let result = parse_query_string(&query);
     assert_eq!(result, Some(expected));
   }
@@ -235,7 +245,7 @@ mod tests {
   fn parse_query_string_decodes_values() {
     let query = "a=a%20b%20c".to_string();
     let expected = hashmap! {
-    "a".to_string() => vec!["a b c".to_string()]
+    "a".to_string() => vec![Some("a b c".to_string())]
   };
     let result = parse_query_string(&query);
     expect!(result).to(be_some().value(expected));
@@ -245,10 +255,27 @@ mod tests {
   fn parse_query_string_decodes_non_ascii_values() {
     let query = "accountNumber=100&anotherValue=%E6%96%87%E4%BB%B6.txt".to_string();
     let expected = hashmap! {
-    "accountNumber".to_string() => vec!["100".to_string()],
-    "anotherValue".to_string() => vec!["文件.txt".to_string()]
+    "accountNumber".to_string() => vec![Some("100".to_string())],
+    "anotherValue".to_string() => vec![Some("文件.txt".to_string())]
   };
     let result = parse_query_string(&query);
     expect!(result).to(be_some().value(expected));
   }
+
+  #[test]
+  fn parse_query_string_handles_no_values() {
+    let query = "a&c=&c&a".to_string();
+    let mut expected = HashMap::new();
+    expected.insert("a".to_string(), vec![None, None]);
+    expected.insert("c".to_string(), vec![Some("".to_string()), None]);
+    let result = parse_query_string(&query);
+    assert_eq!(result, Some(expected));
+  }
+
+  #[rstest]
+  #[case(hashmap!{}, "")]
+  fn build_query_string_test(#[case] map: HashMap<String, Vec<Option<String>>>, #[case] expected: &str) {
+    let result = super::build_query_string(map);
+    assert_eq!(result, expected)
+  }
 }
diff --git a/rust/pact_models/src/request.rs b/rust/pact_models/src/request.rs
index bf1965072..4a1219882 100644
--- a/rust/pact_models/src/request.rs
+++ b/rust/pact_models/src/request.rs
@@ -29,7 +29,7 @@ pub struct Request {
   /// Request path
   pub path: String,
   /// Request query string
-  pub query: Option<HashMap<String, Vec<String>>>,
+  pub query: Option<HashMap<String, Vec<Option<String>>>>,
   /// Request headers
   pub headers: Option<HashMap<String, Vec<String>>>,
   /// Request body
@@ -416,8 +416,8 @@ mod tests {
   #[test]
   fn request_to_json_with_a_query() {
     let request = Request { query: Some(hashmap!{
-        "a".to_string() => vec!["1".to_string(), "2".to_string()],
-        "b".to_string() => vec!["3".to_string()]
+        "a".to_string() => vec![Some("1".to_string()), Some("2".to_string())],
+        "b".to_string() => vec![Some("3".to_string())]
     }), .. Request::default() };
     expect!(request.to_json(&PactSpecification::V2).to_string()).to(
       be_equal_to(r#"{"method":"GET","path":"/","query":"a=1&a=2&b=3"}"#)
@@ -427,8 +427,8 @@ mod tests {
   #[test]
   fn request_to_json_with_a_query_must_encode_the_query() {
     let request = Request { query: Some(hashmap!{
-        "datetime".to_string() => vec!["2011-12-03T10:15:30+01:00".to_string()],
-        "description".to_string() => vec!["hello world!".to_string()] }), .. Request::default() };
+        "datetime".to_string() => vec![Some("2011-12-03T10:15:30+01:00".to_string())],
+        "description".to_string() => vec![Some("hello world!".to_string())] }), .. Request::default() };
     expect!(request.to_json(&PactSpecification::V2).to_string()).to(
       be_equal_to(r#"{"method":"GET","path":"/","query":"datetime=2011-12-03T10%3a15%3a30%2b01%3a00&description=hello+world%21"}"#)
     );
@@ -437,7 +437,7 @@ mod tests {
   #[test]
   fn request_to_json_with_a_query_must_encode_the_query_with_utf8_chars() {
     let request = Request { query: Some(hashmap!{
-        "a".to_string() => vec!["b=c&d❤".to_string()]
+        "a".to_string() => vec![Some("b=c&d❤".to_string())]
     }), .. Request::default() };
     expect!(request.to_json(&PactSpecification::V2).to_string()).to(
       be_equal_to(r#"{"method":"GET","path":"/","query":"a=b%3dc%26d%27%64"}"#)
@@ -447,8 +447,8 @@ mod tests {
   #[test]
   fn request_to_json_with_a_query_v3() {
     let request = Request { query: Some(hashmap!{
-        "a".to_string() => vec!["1".to_string(), "2".to_string()],
-        "b".to_string() => vec!["3".to_string()]
+        "a".to_string() => vec![Some("1".to_string()), Some("2".to_string())],
+        "b".to_string() => vec![Some("3".to_string())]
     }), .. Request::default() };
     expect!(request.to_json(&PactSpecification::V3).to_string()).to(
       be_equal_to(r#"{"method":"GET","path":"/","query":{"a":["1","2"],"b":["3"]}}"#)
@@ -458,8 +458,8 @@ mod tests {
   #[test]
   fn request_to_json_with_a_query_v3_must_not_encode_the_query() {
     let request = Request { query: Some(hashmap!{
-        "datetime".to_string() => vec!["2011-12-03T10:15:30+01:00".to_string()],
-        "description".to_string() => vec!["hello world!".to_string()] }), .. Request::default() };
+        "datetime".to_string() => vec![Some("2011-12-03T10:15:30+01:00".to_string())],
+        "description".to_string() => vec![Some("hello world!".to_string())] }), .. Request::default() };
     expect!(request.to_json(&PactSpecification::V3).to_string()).to(
       be_equal_to(r#"{"method":"GET","path":"/","query":{"datetime":["2011-12-03T10:15:30+01:00"],"description":["hello world!"]}}"#)
     );
@@ -468,7 +468,7 @@ mod tests {
   #[test]
   fn request_to_json_with_a_query_v3_must_not_encode_the_query_with_utf8_chars() {
     let request = Request { query: Some(hashmap!{
-        "a".to_string() => vec!["b=c&d❤".to_string()]
+        "a".to_string() => vec![Some("b=c&d❤".to_string())]
     }), .. Request::default() };
     expect!(request.to_json(&PactSpecification::V3).to_string()).to(
       be_equal_to(r#"{"method":"GET","path":"/","query":{"a":["b=c&d❤"]}}"#)
diff --git a/rust/pact_models/src/sync_pact.rs b/rust/pact_models/src/sync_pact.rs
index 1b2fbf968..bb6de48ba 100644
--- a/rust/pact_models/src/sync_pact.rs
+++ b/rust/pact_models/src/sync_pact.rs
@@ -564,9 +564,9 @@ mod tests {
     expect!(&first_interaction.request.path).to(be_equal_to("/api/v3/klines"));
     expect!(first_interaction.request.body.is_present()).to(be_false());
     expect!(first_interaction.request.query.as_ref().unwrap()).to(be_equal_to(&hashmap!{
-      "interval".to_string() => vec!["1w".to_string()],
-      "limit".to_string() => vec!["1".to_string()],
-      "symbol".to_string() => vec!["LUNCUSDT".to_string()]
+      "interval".to_string() => vec![Some("1w".to_string())],
+      "limit".to_string() => vec![Some("1".to_string())],
+      "symbol".to_string() => vec![Some("LUNCUSDT".to_string())]
     }));
     expect!(first_interaction.request.headers.clone()).to(be_none());
     expect!(first_interaction.response.status).to(be_equal_to(200));
diff --git a/rust/pact_models/src/v4/http_parts.rs b/rust/pact_models/src/v4/http_parts.rs
index d2b9bcb56..6128d6301 100644
--- a/rust/pact_models/src/v4/http_parts.rs
+++ b/rust/pact_models/src/v4/http_parts.rs
@@ -34,7 +34,7 @@ pub struct HttpRequest {
   /// Request path
   pub path: String,
   /// Request query string
-  pub query: Option<HashMap<String, Vec<String>>>,
+  pub query: Option<HashMap<String, Vec<Option<String>>>>,
   /// Request headers
   pub headers: Option<HashMap<String, Vec<String>>>,
   /// Request body
@@ -773,8 +773,8 @@ mod tests {
   #[test]
   fn http_request_to_json_with_a_query() {
     let request = HttpRequest { query: Some(hashmap!{
-        "a".to_string() => vec!["1".to_string(), "2".to_string()],
-        "b".to_string() => vec!["3".to_string()]
+        "a".to_string() => vec![Some("1".to_string()), Some("2".to_string())],
+        "b".to_string() => vec![Some("3".to_string())]
     }), .. HttpRequest::default() };
     expect!(request.to_json().to_string()).to(
       be_equal_to(r#"{"method":"GET","path":"/","query":{"a":["1","2"],"b":["3"]}}"#)
@@ -1142,21 +1142,21 @@ mod tests {
 
     let r5 = HttpRequest {
       query: Some(hashmap!{
-        "q1".to_string() => vec!["1".to_string()],
-        "q2".to_string() => vec!["2".to_string()]
+        "q1".to_string() => vec![Some("1".to_string())],
+        "q2".to_string() => vec![Some("2".to_string())]
       }),
       .. HttpRequest::default()
     };
-    expect!(hash(&r5)).to(be_equal_to(359339694141654691));
+    expect!(hash(&r5)).to(be_equal_to(12415309608656506796));
 
     let r6 = HttpRequest {
       query: Some(hashmap!{
-        "q2".to_string() => vec!["2".to_string()],
-        "q1".to_string() => vec!["1".to_string()]
+        "q2".to_string() => vec![Some("2".to_string())],
+        "q1".to_string() => vec![Some("1".to_string())]
       }),
       .. HttpRequest::default()
     };
-    expect!(hash(&r6)).to(be_equal_to(359339694141654691));
+    expect!(hash(&r6)).to(be_equal_to(12415309608656506796));
 
     let r7 = HttpRequest {
       headers: Some(hashmap!{ "Content-Type".to_string() => vec![ "application/json".to_string() ]  }),
@@ -1200,15 +1200,15 @@ mod tests {
     };
     let r5 = HttpRequest {
       query: Some(hashmap!{
-        "q1".to_string() => vec!["1".to_string()],
-        "q2".to_string() => vec!["2".to_string()]
+        "q1".to_string() => vec![Some("1".to_string())],
+        "q2".to_string() => vec![Some("2".to_string())]
       }),
       .. HttpRequest::default()
     };
     let r6 = HttpRequest {
       query: Some(hashmap!{
-        "q2".to_string() => vec!["1".to_string()],
-        "q1".to_string() => vec!["1".to_string()]
+        "q2".to_string() => vec![Some("1".to_string())],
+        "q1".to_string() => vec![Some("1".to_string())]
       }),
       .. HttpRequest::default()
     };
diff --git a/rust/pact_models/src/v4/pact.rs b/rust/pact_models/src/v4/pact.rs
index 8828b8956..f3f0c3be1 100644
--- a/rust/pact_models/src/v4/pact.rs
+++ b/rust/pact_models/src/v4/pact.rs
@@ -550,7 +550,10 @@ mod tests {
         expect!(request).to(be_equal_to(HttpRequest {
           method: "GET".into(),
           path: "/mallory".into(),
-          query: Some(hashmap!{ "name".to_string() => vec!["ron".to_string()], "status".to_string() => vec!["good".to_string()] }),
+          query: Some(hashmap!{
+            "name".to_string() => vec![Some("ron".to_string())],
+            "status".to_string() => vec![Some("good".to_string())]
+          }),
           headers: None,
           body: OptionalBody::Missing,
           .. HttpRequest::default()
@@ -600,8 +603,10 @@ mod tests {
     match v4pact.interactions[0].as_v4_http() {
       Some(SynchronousHttp { request, .. }) => {
         expect!(&request.query).to(be_equal_to(
-          &Some(hashmap!{ "datetime".to_string() => vec!["2011-12-03T10:15:30+01:00".to_string()],
-            "description".to_string() => vec!["hello world!".to_string()] })));
+          &Some(hashmap!{
+            "datetime".to_string() => vec![Some("2011-12-03T10:15:30+01:00".to_string())],
+            "description".to_string() => vec![Some("hello world!".to_string())]
+          })));
       }
       _ => panic!("Was expecting an HTTP pact")
     }
diff --git a/rust/pact_models/tests/tests.rs b/rust/pact_models/tests/tests.rs
index 52e2cfe41..42917a27b 100644
--- a/rust/pact_models/tests/tests.rs
+++ b/rust/pact_models/tests/tests.rs
@@ -50,9 +50,9 @@ fn write_v4_and_read_v3_pact_test() {
           method: "GET".to_string(),
           path: "/api/v3/klines".to_string(),
           query: Some(hashmap!{
-            "interval".to_string() => vec![ "1w".to_string() ],
-            "limit".to_string() => vec![ "1".to_string() ],
-            "symbol".to_string() => vec![ "LUNCUSDT".to_string() ]
+            "interval".to_string() => vec![ Some("1w".to_string()) ],
+            "limit".to_string() => vec![ Some("1".to_string()) ],
+            "symbol".to_string() => vec![ Some("LUNCUSDT".to_string()) ]
           }),
           .. Request::default()
         },
diff --git a/rust/pact_verifier/src/callback_executors.rs b/rust/pact_verifier/src/callback_executors.rs
index 166ffff54..69a37983b 100644
--- a/rust/pact_verifier/src/callback_executors.rs
+++ b/rust/pact_verifier/src/callback_executors.rs
@@ -139,16 +139,16 @@ impl ProviderStateExecutor for HttpRequestProviderStateExecutor {
           state_change_request.body = OptionalBody::Present(json_body.to_string().into(), Some(JSON.clone()), None);
           state_change_request.headers = Some(hashmap!{ "Content-Type".to_string() => vec!["application/json".to_string()] });
         } else {
-          let mut query = hashmap!{ "state".to_string() => vec![provider_state.name.clone()] };
+          let mut query = hashmap!{ "state".to_string() => vec![Some(provider_state.name.clone())] };
           if setup {
-            query.insert("action".to_string(), vec!["setup".to_string()]);
+            query.insert("action".to_string(), vec![Some("setup".to_string())]);
           } else {
-            query.insert("action".to_string(), vec!["teardown".to_string()]);
+            query.insert("action".to_string(), vec![Some("teardown".to_string())]);
           }
           for (k, v) in provider_state.params.clone() {
             query.insert(k, vec![match v {
-              Value::String(ref s) => s.clone(),
-              _ => v.to_string()
+              Value::String(ref s) => Some(s.clone()),
+              _ => Some(v.to_string())
             }]);
           }
           state_change_request.query = Some(query);
diff --git a/rust/pact_verifier/src/provider_client.rs b/rust/pact_verifier/src/provider_client.rs
index c5535c09e..ac78aaac2 100644
--- a/rust/pact_verifier/src/provider_client.rs
+++ b/rust/pact_verifier/src/provider_client.rs
@@ -368,8 +368,8 @@ mod tests {
     let base_url = "http://example.test:8080".to_string();
     let request = HttpRequest {
       query: Some(hashmap!{
-        "a".to_string() => vec!["b".to_string()],
-        "c".to_string() => vec!["d".to_string(), "e".to_string()]
+        "a".to_string() => vec![Some("b".to_string())],
+        "c".to_string() => vec![Some("d".to_string()), Some("e".to_string())]
       }),
       .. HttpRequest::default()
     };