diff --git a/00-main.go b/00-main.go
index 653212c..71ca830 100644
--- a/00-main.go
+++ b/00-main.go
@@ -66,6 +66,7 @@ func main() {
 		HTTPRetryDelay:        httpRetryDelay,
 		LogContext:            false,
 		LogFunctions:          false,
+		Matchers:              make(map[string]string),
 		MaxHTTPAttempts:       maxHTTPAttempts,
 		Pathnames:             flag.Args(),
 		ResultGathererChannel: make(chan context),
@@ -75,6 +76,12 @@ func main() {
 		WaitGroup:             &sync.WaitGroup{},
 	}
 
+	err = loadMatchers(context)
+
+	if err != nil {
+		panic(err)
+	}
+
 	context.log("00 main")
 
 	go resultGatherer(*context)
diff --git a/05-expected-response-match-parser.go b/05-expected-response-match-parser.go
index c29d2cb..0e5fc61 100644
--- a/05-expected-response-match-parser.go
+++ b/05-expected-response-match-parser.go
@@ -63,29 +63,11 @@ func expectedResponseMatchParser(context *context) {
 
 			reString := "("
 
-			switch parts[i+1] {
-			case ":date":
-				reString +=
-					"(Mon|Tue|Wed|Thu|Fri|Sat|Sun), " +
-						"(0\\d|1\\d|2\\d|3[01]) " +
-						"(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec) " +
-						"2\\d{3} " +
-						"(0\\d|1\\d|2[0-3]):" +
-						"(0\\d|1\\d|2\\d|3\\d|4\\d|5\\d):" +
-						"(0\\d|1\\d|2\\d|3\\d|4\\d|5\\d) " +
-						"(A|M|N|Y|Z|UT|GMT|[A-Z]{3}|[+-](0\\d|1[012]))"
-			case ":b62:22":
-				reString += "[0-9A-Za-z]{22}"
-			case ":iso8601:µs:z":
-				reString += "\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}[.]\\d{6}Z"
-			case ":uuid":
-				reString +=
-					"[[:xdigit:]]{8}-" +
-						"[[:xdigit:]]{4}-" +
-						"[[:xdigit:]]{4}-" +
-						"[[:xdigit:]]{4}-" +
-						"[[:xdigit:]]{12}"
-			default:
+			_, ok := context.Matchers[parts[i+1]]
+
+			if ok {
+				reString += context.Matchers[parts[i+1]]
+			} else {
 				reString += parts[i+1]
 			}
 
diff --git a/Dockerfile b/Dockerfile
index f1de485..664188a 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -8,6 +8,7 @@ RUN apk update   && \
 COPY * /go/src/github.com/tmornini/http-spec/
 
 RUN cd /go/src/github.com/tmornini/http-spec && \
+    go get ./...                             && \
     go install .
 
 WORKDIR /
diff --git a/README.md b/README.md
index 65e7c86..0be1865 100644
--- a/README.md
+++ b/README.md
@@ -71,6 +71,8 @@ MAINTAINER Tom Mornini <tmornini@incentivenetworks.com>
 COPY run-http-specs /run-http-specs
 
 COPY *.htsf /
+
+COPY matchers.yml /
 ```
 
 ## Basic Usage
@@ -155,6 +157,24 @@ for 128+ bit UUIDs.
 ⧆optional-name⧆:iso8601:µs:z⧆ is a matcher for ISO 8601 format timestamps
 with microsecond resolution and zulu (Z) timezone.
 
+## Custom Matchers
+
+Custom matchers work just like built-in matchers and are loaded from an optionally
+provided matchers.yml file in the docker container. See the example-Dockerfile and
+matchers.yml file.
+
+The matchers.yml file is a basic YAML file with the keys coresponding to the mandatory-regexp
+portion of the matcher and the value corresponding to the actual regexp.
+
+matchers.yml example:
+```
+RFC4122v4: "[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}"
+```
+usage of the custom matcher:
+```
+⧆optional-name⧆:RFC4122v4⧆
+```
+
 ## Built-in Substitutes
 
     ⧈YYYY-MM-DD⧈ is a substitute for today's date
diff --git a/example-Dockerfile b/example-Dockerfile
index d17562f..76fda95 100644
--- a/example-Dockerfile
+++ b/example-Dockerfile
@@ -4,3 +4,5 @@ MAINTAINER Tom Mornini <tmornini@incentivenetworks.com>
 COPY run-http-specs /run-http-specs
 
 COPY *.htsf /
+
+COPY matchers.yml /
diff --git a/example-custom-matcher.htsf b/example-custom-matcher.htsf
new file mode 100644
index 0000000..2c89ed0
--- /dev/null
+++ b/example-custom-matcher.htsf
@@ -0,0 +1,15 @@
+> GET https://api.subledger.com/v3/system/status HTTP/1.1
+>
+
+< HTTP/1.1 200 OK
+< Connection: keep-alive
+< Content-Security-Policy: default-src https: data: 'unsafe-inline' 'unsafe-eval'
+< Date: ⧆⧆:date⧆
+< Public-Key-Pins: pin-sha256="⧆⧆[^"]+⧆"; pin-sha256="⧆⧆[^"]+⧆"; max-age=300
+< Server: nginx
+< Strict-Transport-Security: max-age=10886400; includeSubDomains; preload
+< X-Content-Type-Options: nosniff
+< X-Frame-Options: ⧆⧆:same-origin⧆
+< X-Xss-Protection: 1; mode=block
+<
+< {"dynamodb":true,"sqs":true,"redis":true}
diff --git a/example-do-not-follow-redirect.htsf b/example-do-not-follow-redirect.htsf
index 7d9bfb0..223910d 100644
--- a/example-do-not-follow-redirect.htsf
+++ b/example-do-not-follow-redirect.htsf
@@ -6,7 +6,7 @@
 < Content-Type: text/html;charset=ISO-8859-1
 < Date: ⧆⧆:date⧆
 < Location: https://jigsaw.w3.org/HTTP/300/Overview.html
-< Public-Key-Pins: pin-sha256="cN0QSpPIkuwpT6iP2YjEo1bEwGpH/yiUn6yhdy+HNto="; pin-sha256="WGJkyYjx1QMdMe0UqlyOKXtydPDVrk7sl2fV+nNm1r4="; pin-sha256="LrKdTxZLRTvyHM4/atX2nquX9BeHRZMCxg3cf4rhc2I="; max-age=864000
+< Public-Key-Pins: pin-sha256="⧆⧆[^"]+⧆"; pin-sha256="⧆⧆[^"]+⧆"; pin-sha256="⧆⧆[^"]+⧆"; max-age=864000
 < Server: Jigsaw/2.3.0-beta⧆⧆\d+⧆
 < Strict-Transport-Security: max-age=15552015; includeSubDomains; preload
 < X-Frame-Options: deny
diff --git a/example-not-found.htsf b/example-not-found.htsf
index 55f76e2..b73764d 100644
--- a/example-not-found.htsf
+++ b/example-not-found.htsf
@@ -7,7 +7,7 @@
 < Content-Security-Policy: default-src https: data: 'unsafe-inline' 'unsafe-eval'
 < Content-Type: text/html
 < Date: ⧆⧆:date⧆
-< Public-Key-Pins: pin-sha256="NRx3RbA+pNNyfX8GvCJGysRCFQJnqiNhM+u8dVaqn90="; pin-sha256="wn7UqCaQr4O5YYeHLnz52CD6jasiTYyFz0plWceOlgM="; max-age=300
+< Public-Key-Pins: pin-sha256="⧆⧆[^"]+⧆"; pin-sha256="⧆⧆[^"]+⧆"; max-age=300
 < Server: nginx
 < Strict-Transport-Security: max-age=10886400; includeSubDomains; preload
 < X-Content-Type-Options: nosniff
diff --git a/example-post.htsf b/example-post.htsf
index 8f35919..dd6dbb5 100644
--- a/example-post.htsf
+++ b/example-post.htsf
@@ -14,7 +14,7 @@
 < Content-Security-Policy: default-src https: data: 'unsafe-inline' 'unsafe-eval'
 < Content-Type: application/json
 < Date: ⧆⧆:date⧆
-< Public-Key-Pins: pin-sha256="NRx3RbA+pNNyfX8GvCJGysRCFQJnqiNhM+u8dVaqn90="; pin-sha256="wn7UqCaQr4O5YYeHLnz52CD6jasiTYyFz0plWceOlgM="; max-age=300
+< Public-Key-Pins: pin-sha256="⧆⧆[^"]+⧆"; pin-sha256="⧆⧆[^"]+⧆"; max-age=300
 < Server: nginx
 < Strict-Transport-Security: max-age=10886400; includeSubDomains; preload
 < Vary: Origin
@@ -34,7 +34,7 @@
 < Connection: keep-alive
 < Content-Security-Policy: default-src https: data: 'unsafe-inline' 'unsafe-eval'
 < Date: ⧆⧆:date⧆
-< Public-Key-Pins: pin-sha256="NRx3RbA+pNNyfX8GvCJGysRCFQJnqiNhM+u8dVaqn90="; pin-sha256="wn7UqCaQr4O5YYeHLnz52CD6jasiTYyFz0plWceOlgM="; max-age=300
+< Public-Key-Pins: pin-sha256="⧆⧆[^"]+⧆"; pin-sha256="⧆⧆[^"]+⧆"; max-age=300
 < Server: nginx
 < Strict-Transport-Security: max-age=10886400; includeSubDomains; preload
 < Www-Authenticate: Basic realm="Subledger API v2"
diff --git a/example-regexp-and-substitution.htsf b/example-regexp-and-substitution.htsf
index 2384399..0f157b3 100644
--- a/example-regexp-and-substitution.htsf
+++ b/example-regexp-and-substitution.htsf
@@ -5,7 +5,7 @@
 < Connection: keep-alive
 < Content-Security-Policy: default-src https: data: 'unsafe-inline' 'unsafe-eval'
 < Date: ⧆⧆:date⧆
-< Public-Key-Pins: pin-sha256="NRx3RbA+pNNyfX8GvCJGysRCFQJnqiNhM+u8dVaqn90="; pin-sha256="wn7UqCaQr4O5YYeHLnz52CD6jasiTYyFz0plWceOlgM="; max-age=300
+< Public-Key-Pins: pin-sha256="⧆⧆[^"]+⧆"; pin-sha256="⧆⧆[^"]+⧆"; max-age=300
 < Server: nginx
 < Strict-Transport-Security: max-age=10886400; includeSubDomains; preload
 < X-Content-Type-Options: nosniff
@@ -21,7 +21,7 @@
 < Connection: keep-alive
 < Content-Security-Policy: default-src https: data: 'unsafe-inline' 'unsafe-eval'
 < Date: ⧆⧆:date⧆
-< Public-Key-Pins: pin-sha256="NRx3RbA+pNNyfX8GvCJGysRCFQJnqiNhM+u8dVaqn90="; pin-sha256="wn7UqCaQr4O5YYeHLnz52CD6jasiTYyFz0plWceOlgM="; max-age=300
+< Public-Key-Pins: pin-sha256="⧆⧆[^"]+⧆"; pin-sha256="⧆⧆[^"]+⧆"; max-age=300
 < Server: nginx
 < Strict-Transport-Security: max-age=10886400; includeSubDomains; preload
 < X-Content-Type-Options: nosniff
diff --git a/example-scheme-and-hostname-2.htsf b/example-scheme-and-hostname-2.htsf
index 65eedef..516e06c 100644
--- a/example-scheme-and-hostname-2.htsf
+++ b/example-scheme-and-hostname-2.htsf
@@ -5,7 +5,7 @@
 < Connection: keep-alive
 < Content-Security-Policy: default-src https: data: 'unsafe-inline' 'unsafe-eval'
 < Date: ⧆⧆:date⧆
-< Public-Key-Pins: pin-sha256="NRx3RbA+pNNyfX8GvCJGysRCFQJnqiNhM+u8dVaqn90="; pin-sha256="wn7UqCaQr4O5YYeHLnz52CD6jasiTYyFz0plWceOlgM="; max-age=300
+< Public-Key-Pins: pin-sha256="⧆⧆[^"]+⧆"; pin-sha256="⧆⧆[^"]+⧆"; max-age=300
 < Server: nginx
 < Strict-Transport-Security: max-age=10886400; includeSubDomains; preload
 < X-Content-Type-Options: nosniff
diff --git a/example-sleep.htsf b/example-sleep.htsf
index 8b7d321..19b668c 100644
--- a/example-sleep.htsf
+++ b/example-sleep.htsf
@@ -5,7 +5,7 @@
 < Connection: keep-alive
 < Content-Security-Policy: default-src https: data: 'unsafe-inline' 'unsafe-eval'
 < Date: ⧆⧆:date⧆
-< Public-Key-Pins: pin-sha256="NRx3RbA+pNNyfX8GvCJGysRCFQJnqiNhM+u8dVaqn90="; pin-sha256="wn7UqCaQr4O5YYeHLnz52CD6jasiTYyFz0plWceOlgM="; max-age=300
+< Public-Key-Pins: pin-sha256="⧆⧆[^"]+⧆"; pin-sha256="⧆⧆[^"]+⧆"; max-age=300
 < Server: nginx
 < Strict-Transport-Security: max-age=10886400; includeSubDomains; preload
 < X-Content-Type-Options: nosniff
@@ -21,7 +21,7 @@
 < Connection: keep-alive
 < Content-Security-Policy: default-src https: data: 'unsafe-inline' 'unsafe-eval'
 < Date: ⧆⧆:date⧆
-< Public-Key-Pins: pin-sha256="NRx3RbA+pNNyfX8GvCJGysRCFQJnqiNhM+u8dVaqn90="; pin-sha256="wn7UqCaQr4O5YYeHLnz52CD6jasiTYyFz0plWceOlgM="; max-age=300
+< Public-Key-Pins: pin-sha256="⧆⧆[^"]+⧆"; pin-sha256="⧆⧆[^"]+⧆"; max-age=300
 < Server: nginx
 < Strict-Transport-Security: max-age=10886400; includeSubDomains; preload
 < X-Content-Type-Options: nosniff
diff --git a/example-uuid.htsf b/example-uuid.htsf
index 06d063e..d6a3aea 100644
--- a/example-uuid.htsf
+++ b/example-uuid.htsf
@@ -5,7 +5,7 @@
 < Connection: keep-alive ⧆⧆:uuid⧆
 < Content-Security-Policy: default-src https: data: 'unsafe-inline' 'unsafe-eval'
 < Date: ⧆⧆:date⧆
-< Public-Key-Pins: pin-sha256="hEJVeNxwqLnjseFv/doE3XU6Nr/hXJnoKdhn12iwavY="; pin-sha256="cTduB9g7EP4xd2glLUNhEq40f/jtyJF24dTzgVuKsZk="; max-age=300
+< Public-Key-Pins: pin-sha256="⧆⧆[^"]+⧆"; pin-sha256="⧆⧆[^"]+⧆"; max-age=300
 < Server: nginx
 < Strict-Transport-Security: max-age=10886400; includeSubDomains; preload
 < X-Content-Type-Options: nosniff
diff --git a/load-matchers.go b/load-matchers.go
new file mode 100644
index 0000000..f0439f0
--- /dev/null
+++ b/load-matchers.go
@@ -0,0 +1,43 @@
+package main
+
+import (
+	"errors"
+	"io/ioutil"
+
+	yaml "gopkg.in/yaml.v2"
+)
+
+func loadMatchers(context *context) error {
+	// load default matchers
+	context.Matchers[":date"] = "(Mon|Tue|Wed|Thu|Fri|Sat|Sun), (0\\d|1\\d|2\\d|3[01]) (Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec) 2\\d{3} (0\\d|1\\d|2[0-3]):(0\\d|1\\d|2\\d|3\\d|4\\d|5\\d):(0\\d|1\\d|2\\d|3\\d|4\\d|5\\d) (A|M|N|Y|Z|UT|GMT|[A-Z]{3}|[+-](0\\d|1[012]))"
+	context.Matchers[":b62:22"] = "[0-9A-Za-z]{22}"
+	context.Matchers[":iso8601:µs:z"] = "\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}[.]\\d{6}Z"
+	context.Matchers[":uuid"] = "[[:xdigit:]]{8}-[[:xdigit:]]{4}-[[:xdigit:]]{4}-[[:xdigit:]]{4}-[[:xdigit:]]{12}"
+
+	// load custom matchers if provided
+	var ymlData map[string]string
+
+	ymlFile, err := ioutil.ReadFile("/matchers.yml")
+	// ignore error (perhaps they didn't provide a custom matcher file)
+	if err == nil {
+		err = yaml.Unmarshal(ymlFile, &ymlData)
+
+		if err != nil {
+			return err
+		}
+
+		for key, value := range ymlData {
+			trueKey := ":" + key
+
+			_, ok := context.Matchers[trueKey]
+
+			if ok {
+				return errors.New(key + " is a default matcher and cannot be used")
+			}
+
+			context.Matchers[trueKey] = value
+		}
+	}
+
+	return nil
+}
diff --git a/matchers.yml b/matchers.yml
new file mode 100644
index 0000000..1ce7b8e
--- /dev/null
+++ b/matchers.yml
@@ -0,0 +1,3 @@
+RFC3339: "\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}Z"
+RFC4122v4: "[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}"
+same-origin: SAMEORIGIN
diff --git a/run-http-specs b/run-http-specs
index 4b360b3..b568475 100755
--- a/run-http-specs
+++ b/run-http-specs
@@ -17,6 +17,8 @@ time (
 
   http-spec example-built-in-substitution.htsf           || exit 1
 
+  http-spec example-custom-matcher.htsf                  || exit 1
+
   http-spec -hostname api.subledger.com -scheme http     \
             example-scheme-and-hostname-1.htsf           || exit 1
 
diff --git a/type-context.go b/type-context.go
index 628cfd1..363665e 100644
--- a/type-context.go
+++ b/type-context.go
@@ -18,6 +18,7 @@ type context struct {
 	ID                    *big.Int
 	LogContext            bool
 	LogFunctions          bool
+	Matchers              map[string]string
 	MaxHTTPAttempts       int
 	Pathname              string
 	Pathnames             []string