diff --git a/wiring/inc/spark_wiring_ledger_v1.h b/wiring/inc/spark_wiring_ledger_v1.h
new file mode 100644
index 0000000000..36661bfe11
--- /dev/null
+++ b/wiring/inc/spark_wiring_ledger_v1.h
@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2023 Particle Industries, Inc.  All rights reserved.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "spark_wiring_variant.h"
+
+namespace particle {
+
+/**
+ * A ledger.
+ *
+ * Use `Particle.ledger()` to create an instance of this class.
+ */
+class Ledger {
+public:
+    /**
+     * A callback invoked when the ledger data has been synchronized with the Cloud.
+     *
+     * @param ledger Ledger instance.
+     * @param userData User data.
+     */
+    typedef void (*OnSyncCallback)(Ledger ledger, void* userData);
+
+    /**
+     * Default constructor.
+     *
+     * Constructs an invalid ledger instance.
+     */
+    Ledger();
+
+    /**
+     * Set the ledger data.
+     *
+     * This method replaces the current contents of the ledger.
+     *
+     * @param data New ledger data.
+     * @return 0 on success, otherwise an error code defined by `Error::Type`.
+     */
+    int set(const Variant& data);
+
+    /**
+     * Update the ledger data.
+     *
+     * This method partially updates the contents of the ledger.
+     *
+     * @param data New ledger data.
+     * @return 0 on success, otherwise an error code defined by `Error::Type`.
+     */
+    int merge(const Variant& data);
+
+    /**
+     * Get the ledger data.
+     *
+     * @return Ledger data.
+     */
+    Variant get() const;
+
+    /**
+     * Get the last time, in milliseconds since the Unix epoch, when the ledger was synchronized with the Cloud.
+     *
+     * @return Time the ledger was synchronized with the Cloud, or 0 if the ledger was never synchronized.
+     */
+    time64_t lastSyncedAt() const;
+
+    /**
+     * Get the ledger name.
+     *
+     * @return Ledger name.
+     */
+    const char* name() const;
+
+    /**
+     * Set a callback to be invoked when the ledger data has been synchronized with the Cloud.
+     *
+     * @param callback Callback.
+     * @param userData User data.
+     */
+    void onSync(OnSyncCallback callback, void* userData = nullptr);
+    // TODO: Add an overload taking a functor object
+};
+
+} // namespace particle
diff --git a/wiring/inc/spark_wiring_ledger_v2.h b/wiring/inc/spark_wiring_ledger_v2.h
new file mode 100644
index 0000000000..d36c0b83ab
--- /dev/null
+++ b/wiring/inc/spark_wiring_ledger_v2.h
@@ -0,0 +1,152 @@
+/*
+ * Copyright (c) 2023 Particle Industries, Inc.  All rights reserved.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "spark_wiring_variant.h"
+#include "spark_wiring_print.h"
+
+namespace particle {
+
+class LedgerData;
+
+/**
+ * A ledger.
+ *
+ * Use `Particle.ledger()` to create an instance of this class.
+ */
+class Ledger {
+public:
+    /**
+     * A callback invoked when the ledger data has been synchronized with the Cloud.
+     *
+     * @param ledger Ledger instance.
+     * @param userData User data.
+     */
+    typedef void (*OnSyncCallback)(Ledger ledger, void* userData);
+
+    /**
+     * Default constructor.
+     *
+     * Constructs an invalid ledger instance.
+     */
+    Ledger();
+
+    /**
+     * Set the ledger data.
+     *
+     * This method replaces the current contents of the ledger.
+     *
+     * @param data New ledger data.
+     * @return 0 on success, otherwise an error code defined by `Error::Type`.
+     */
+    int set(const LedgerData& data);
+
+    /**
+     * Update the ledger data.
+     *
+     * This method replaces the current contents of the ledger.
+     *
+     * @param data New ledger data.
+     * @return 0 on success, otherwise an error code defined by `Error::Type`.
+     */
+    int update(const LedgerData& data);
+
+    /**
+     * Get the ledger data.
+     *
+     * @return Ledger data.
+     */
+    LedgerData get() const;
+
+    /**
+     * Get the last time, in milliseconds since the Unix epoch, the ledger was synchronized with the Cloud.
+     *
+     * @return Time the ledger was synchronized with the Cloud, or 0 if the ledger was never synchronized.
+     */
+    time64_t lastSyncedAt() const;
+
+    /**
+     * Get the ledger name.
+     *
+     * @return Ledger name.
+     */
+    const char* name() const;
+
+    /**
+     * Set a callback to be invoked when the ledger data has been synchronized with the Cloud.
+     *
+     * @param callback Callback.
+     * @param userData User data.
+     */
+    void onSync(OnSyncCallback callback, void* userData = nullptr);
+    // TODO: Add an overload taking a functor object
+};
+
+/**
+ * Ledger data.
+ */
+class LedgerData {
+public:
+    /**
+     * Set the value of an entry.
+     *
+     * @param name Entry name.
+     * @param value Entry value.
+     * @return `true` if the value was set, otherwise `false`.
+     */
+    bool set(const char* name, Variant value);
+
+    /**
+     * Get the value of an entry.
+     *
+     * @param name Entry name.
+     * @return Entry value.
+     */
+    Variant get(const char* name) const;
+
+    /**
+     * Check if an entry with a given name exists.
+     *
+     * @param name Entry name.
+     * @return `true` if the entry exists, otherwise `false`.
+     */
+    bool has(const char* name) const;
+
+    /**
+     * Remove an entry.
+     *
+     * @param name Entry name.
+     * @return `true` if the entry was removed, otherwise `false`.
+     */
+    bool remove(const char* name);
+
+private:
+    enum EntryFlag {
+        SET = 0x01,
+        REMOVED = 0x02
+    };
+
+    struct Entry {
+        Variant data;
+        int flags;
+    };
+
+    Map<String, Entry> entries_;
+};
+
+} // namespace particle
diff --git a/wiring/inc/spark_wiring_map.h b/wiring/inc/spark_wiring_map.h
new file mode 100644
index 0000000000..a9179d47d7
--- /dev/null
+++ b/wiring/inc/spark_wiring_map.h
@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2023 Particle Industries, Inc.  All rights reserved.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <functional>
+#include <utility>
+
+#include "spark_wiring_vector.h"
+
+namespace particle {
+
+template<typename KeyT, typename ValueT, typename CompareT = std::less<KeyT>>
+class Map {
+public:
+    typedef std::tuple<KeyT, ValueT> Entry;
+
+    Map() = default;
+    Map(const Map& map);
+    Map(Map&& map);
+
+    bool set(KeyT key, ValueT value);
+    ValueT get(const KeyT& key, ValueT defaultValue = ValueT()) const;
+    ValueT take(const KeyT& key, ValueT defaultValue = ValueT());
+    bool remove(const KeyT& key);
+    bool has(const KeyT& key) const;
+
+    const Vector<Entry>& entries() const;
+
+    int size() const;
+    bool isEmpty() const;
+
+    bool reserve(int n);
+    int capacity() const;
+    bool trimToSize();
+
+    ValueT& operator[](int index);
+
+    // TODO: Iterator-based API
+
+    Map& operator=(Map map);
+
+    bool operator==(const Map& map);
+
+    friend void swap(Map& map1, Map& map2);
+
+private:
+    Vector<Entry> entries_; // Sorted
+    CompareT cmp_;
+};
+
+} // namespace particle
diff --git a/wiring/inc/spark_wiring_variant.h b/wiring/inc/spark_wiring_variant.h
new file mode 100644
index 0000000000..e82ccfc9e1
--- /dev/null
+++ b/wiring/inc/spark_wiring_variant.h
@@ -0,0 +1,137 @@
+/*
+ * Copyright (c) 2023 Particle Industries, Inc.  All rights reserved.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <variant>
+#include <cstdint>
+
+#include "spark_wiring_string.h"
+#include "spark_wiring_stream.h"
+#include "spark_wiring_vector.h"
+#include "spark_wiring_map.h"
+
+namespace particle {
+
+class Variant;
+
+typedef Vector<Variant> VariantArray;
+typedef Map<Variant, Variant> VariantMap;
+
+class Variant {
+public:
+    enum Type {
+        // INVALID,
+        NULL_,
+        BOOL,
+        INT,
+        INT64,
+        DOUBLE,
+        STRING,
+        ARRAY,
+        MAP
+    };
+
+    Variant() = default;
+
+    Variant(bool value);
+    Variant(char value);
+    Variant(unsigned char value);
+    Variant(short value);
+    Variant(unsigned short value);
+    Variant(int value);
+    Variant(unsigned value);
+    Variant(long value);
+    Variant(unsigned long value);
+    Variant(long long value);
+    Variant(unsigned long long value);
+    Variant(double value);
+    Variant(const char* value);
+    Variant(String value);
+    Variant(VariantArray value);
+    Variant(VariantMap value);
+
+    Variant(const Variant& variant);
+    Variant(Variant&& variant);
+
+    Type type() const;
+
+    // bool isValid() const;
+    bool isNull() const;
+    bool isBool() const;
+    bool isInt() const;
+    bool isInt64() const;
+    bool isDouble() const;
+    bool isString() const;
+    bool isArray() const;
+    bool isMap() const;
+
+    bool toBool() const;
+    int toInt() const;
+    int64_t toInt64() const;
+    double toDouble() const;
+    String toString() const;
+    VariantArray toArray() const;
+    VariantMap toMap() const;
+
+    // TODO: Add helper methods for in-place modification of array, map and string variants -
+    // see the Vector, Map and String classes respectively
+
+    String toJson() const;
+    void toJson(Print& stream) const;
+
+    template<typename T>
+    T valueAs();
+
+    template<typename T>
+    T& valueRef();
+
+    template<typename T>
+    const T& valueRef() const;
+
+    Variant& operator=(Variant variant);
+
+    bool operator==(const Variant& variant) const;
+    bool operator<(const Variant& variant) const;
+
+    // Conversion operators
+    operator bool() const;
+    operator char() const;
+    operator unsigned char() const;
+    operator short() const;
+    operator unsigned short() const;
+    operator int() const;
+    operator unsigned() const;
+    operator int64_t() const;
+    operator double() const;
+    operator const char*() const;
+    operator String() const;
+    operator VariantArray() const;
+    operator VariantMap() const;
+
+    static Variant fromJson(const char* str);
+    static Variant fromJson(Stream& stream);
+
+    friend void swap(Variant& variant1, Variant& variant2);
+
+private:
+    using VariantType = std::variant<std::monostate, bool, int, int64_t, double, String, VariantArray, VariantMap>;
+
+    VariantType v_;
+};
+
+} // namespace particle