diff --git a/.github/workflows/cpp-internal.yml b/.github/workflows/cpp-internal.yml
index 71c94dd8..c03450da 100644
--- a/.github/workflows/cpp-internal.yml
+++ b/.github/workflows/cpp-internal.yml
@@ -1,18 +1,11 @@
 name: C++ Internal
-
 on:
   schedule:
-    - cron: 0 1 * * *  # Nightly at 01:00 UTC
+    - cron: 0 1 * * * # Nightly at 01:00 UTC
   push:
     branches:
       - master
   pull_request:
-  workflow_dispatch:
-    inputs:
-      extra_resolve_options:
-        description: Extra Resolve Options
-        required: false
-
 jobs:
   linux_cmake:
     timeout-minutes: 45
@@ -47,18 +40,16 @@ jobs:
       - ${{ matrix.config.runner }}
     name: ${{ matrix.config.name }}
     steps:
-      # This is sometimes needed when running docker builds since these
-      # sometimes produce files with root ownership
       - name: Ensure correct owner of repository
         run: sudo chown -R actions-runner:actions-runner .
       - name: Checkout source code
         uses: actions/checkout@v3
-      - name: Waf Clean
-        run: python3 waf clean --no_resolve
       - name: Waf Configure
         run: python3 waf configure --git_protocol=git@ --cmake_toolchain=${{ matrix.config.toolchain }} --cmake_verbose
       - name: Waf Build
-        run: python3 waf build --run_tests
+        run: python3 waf build
+      - name: Waf Run Tests
+        run: python3 waf --run_tests
 
   valgrind:
     timeout-minutes: 45
@@ -70,41 +61,40 @@ jobs:
     steps:
       - name: Ensure correct owner of repository
         run: sudo chown -R actions-runner:actions-runner .
-
       - name: Checkout source code
         uses: actions/checkout@v3
-
-      - name: Waf Clean
-        run: python3 waf clean --no_resolve
-
       - name: Waf Configure
         run: python3 waf configure --git_protocol=git@ --cmake_toolchain=./resolve_symlinks/toolchains/gcc-toolchain.cmake --cmake_verbose
-
       - name: Waf Build
-        run: python3 waf build --run_tests --ctest_valgrind
-
+        run: python3 waf build
+      - name: Waf Run Tests
+        run: python3 waf --run_tests --ctest_valgrind
   zig_toolchain_build:
     name: Zig Toolchain Build (Docker)
     runs-on: [self-hosted, vm, ubuntu-current]
     container:
-      image: kassany/bookworm-ziglang
+      image: ghcr.io/steinwurf/build-images/zig-cpp
       options: --user 0:0
-      volumes:
-        - /root/.ssh:/root/.ssh
     steps:
       - name: Checkout source code
         uses: actions/checkout@v4
-      - name: Install dependencies
+        with:
+          persist-credentials: false
+      - name: Configure Github Authentication
         run: |
-          apt-get update
-          apt-get install -y python3 python3-pip git cmake build-essential
-      - name: Waf Clean
-        run: python3 waf clean --no_resolve
+          git config --global credential.helper 'store'
+          git credential approve <<EOF
+          protocol=https
+          host=github.com
+          username=x-access-token
+          password=${{ secrets.GH_ACCESS_TOKEN }}
+          EOF
       - name: Waf Configure with Zig Toolchain
-        run: python3 waf configure --git_protocol=git@ --cmake_toolchain=../resolve_symlinks/toolchains/zig-toolchain-x86_64-linux-musl.cmake --cmake_verbose
+        run: python3 waf configure --git_protocol=https:// --cmake_toolchain=./resolve_symlinks/toolchains/zig-toolchain-x86_64-linux-musl.cmake --cmake_verbose
       - name: Waf Build with Zig Toolchain
-        run: python3 waf build --run_tests
-
+        run: python3 waf build
+      - name: Waf Run Tests
+        run: python3 waf --run_tests
   macos_cmake:
     timeout-minutes: 45
     strategy:
@@ -126,13 +116,12 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v3
-      - name: Waf Clean
-        run: python3 waf clean --no_resolve
       - name: Waf Configure
         run: python3 waf configure --git_protocol=git@ --cmake_toolchain=${{ matrix.config.toolchain }} --cmake_verbose
       - name: Waf Build
-        run: python3 waf build --run_tests
-
+        run: python3 waf build
+      - name: Waf Run Tests
+        run: python3 waf --run_tests
   windows_cmake:
     timeout-minutes: 45
     strategy:
@@ -142,13 +131,12 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v3
-      - name: Waf Clean
-        run: python waf clean --no_resolve
       - name: Waf Configure
         run: python waf configure --git_protocol=git@ --cmake_verbose
       - name: Waf Build
-        run: python waf build --run_tests
-
+        run: python waf build
+      - name: Waf Run Tests
+        run: python waf --run_tests
   clang-format:
     timeout-minutes: 45
     name: Clang-Format
@@ -162,7 +150,6 @@ jobs:
         uses: actions/checkout@v3
       - name: Run Clang-format
         run: find ./ -iname *.hpp -o -iname *.cpp -o -iname *.c -o -iname *.h | xargs clang-format --dry-run --Werror
-
   workflow-keepalive:
     if: github.event_name == 'schedule'
     runs-on: [self-hosted, vm, ubuntu-current]
@@ -174,7 +161,6 @@ jobs:
           sudo apt update
           sudo apt install -y gh
       - uses: liskin/gh-workflow-keepalive@v1
-
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref || github.run_id }}
   cancel-in-progress: true
\ No newline at end of file
diff --git a/NEWS.rst b/NEWS.rst
index a650fe7e..e1fc1f4c 100644
--- a/NEWS.rst
+++ b/NEWS.rst
@@ -6,7 +6,10 @@ every change, see the Git log.
 
 Latest
 ------
-* tbd
+* Minor: Added ``json::parse_options`` and new ``json::parse`` overloads for
+  strict parsing.
+* Minor: Added ``bourne::error::parse_object_duplicate_key`` when strict
+  parsing detects duplicate object keys.
 
 11.0.0
 ------
diff --git a/README.rst b/README.rst
index fbb48e43..a57b486e 100644
--- a/README.rst
+++ b/README.rst
@@ -49,6 +49,29 @@ Usage
 
 Usage example is located in the examples folder.
 
+Strict Parsing
+==============
+
+By default, parsing is permissive and later values overwrite earlier ones if
+an object contains duplicate keys.
+
+To enable strict parsing, pass ``parse_options`` with ``strict = true``. In
+strict mode, parsing fails with
+``bourne::error::parse_object_duplicate_key`` when duplicate keys are found.
+
+::
+
+   bourne::json::parse_options options;
+   options.strict = true;
+
+   std::error_code error;
+   auto result = bourne::json::parse("{\"a\":1,\"a\":2}", options, error);
+
+   if (error == bourne::error::parse_object_duplicate_key)
+   {
+       // duplicate key found
+   }
+
 Build
 =====
 
diff --git a/src/bourne/detail/error_tags.hpp b/src/bourne/detail/error_tags.hpp
index 8e196ad0..9a0ed5b0 100644
--- a/src/bourne/detail/error_tags.hpp
+++ b/src/bourne/detail/error_tags.hpp
@@ -8,6 +8,7 @@ BOURNE_ERROR_TAG(parse_found_multiple_unstructured_elements,
                  "Found multiple unstructured elements.")
 BOURNE_ERROR_TAG(parse_object_expected_colon, "Expected \":\"")
 BOURNE_ERROR_TAG(parse_object_expected_comma, "Expected \",\"")
+BOURNE_ERROR_TAG(parse_object_duplicate_key, "Duplicate key in object")
 BOURNE_ERROR_TAG(parse_array_expected_comma_or_closing_bracket,
                  "Expected \",\" or \"]\"")
 BOURNE_ERROR_TAG(parse_string_expected_unicode_escape_hex_char,
diff --git a/src/bourne/detail/parser.cpp b/src/bourne/detail/parser.cpp
index 2683c33a..13a29420 100644
--- a/src/bourne/detail/parser.cpp
+++ b/src/bourne/detail/parser.cpp
@@ -22,18 +22,40 @@ inline namespace STEINWURF_BOURNE_VERSION
 namespace detail
 {
 json parser::parse(const std::string& input)
+{
+    return parse(input, json::parse_options{});
+}
+
+json parser::parse(const std::string& input, const json::parse_options& options)
 {
     std::error_code error;
     std::size_t offset = 0;
-    auto result = parse_next(input, offset, error);
+    auto result = parse_next(input, offset, error, options);
+    if (error)
+    {
+        throw_if_error(error);
+    }
+    consume_white_space(input, offset);
+    if (offset != input.size())
+    {
+        error = bourne::error::parse_found_multiple_unstructured_elements;
+        throw_if_error(error);
+    }
     throw_if_error(error);
     return result;
 }
+
 json parser::parse(const std::string& input, std::error_code& error)
+{
+    return parse(input, json::parse_options{}, error);
+}
+
+json parser::parse(const std::string& input, const json::parse_options& options,
+                   std::error_code& error)
 {
     assert(!error);
     std::size_t offset = 0;
-    auto result = parse_next(input, offset, error);
+    auto result = parse_next(input, offset, error, options);
     if (error)
         return result;
     consume_white_space(input, offset);
@@ -55,7 +77,8 @@ void parser::consume_white_space(const std::string& input, size_t& offset)
 }
 
 json parser::parse_object(const std::string& input, size_t& offset,
-                          std::error_code& error)
+                          std::error_code& error,
+                          const json::parse_options& options)
 {
     assert(!error);
     json object = json(class_type::object);
@@ -70,7 +93,7 @@ json parser::parse_object(const std::string& input, size_t& offset,
 
     while (true)
     {
-        json key = parse_next(input, offset, error);
+        json key = parse_next(input, offset, error, options);
         if (error)
             return json(class_type::null);
 
@@ -82,11 +105,17 @@ json parser::parse_object(const std::string& input, size_t& offset,
         }
         offset++;
         consume_white_space(input, offset);
-        json value = parse_next(input, offset, error);
+        json value = parse_next(input, offset, error, options);
         if (error)
             return json(class_type::null);
 
-        object[key.to_string()] = value;
+        std::string key_string = key.to_string();
+        if (options.strict && object.has_key(key_string))
+        {
+            error = bourne::error::parse_object_duplicate_key;
+            return json(class_type::null);
+        }
+        object[key_string] = value;
 
         consume_white_space(input, offset);
         if (input[offset] == ',')
@@ -110,7 +139,8 @@ json parser::parse_object(const std::string& input, size_t& offset,
 }
 
 json parser::parse_array(const std::string& input, size_t& offset,
-                         std::error_code& error)
+                         std::error_code& error,
+                         const json::parse_options& options)
 {
     assert(!error);
     json array = json(class_type::array);
@@ -126,7 +156,7 @@ json parser::parse_array(const std::string& input, size_t& offset,
 
     while (true)
     {
-        array[index++] = parse_next(input, offset, error);
+        array[index++] = parse_next(input, offset, error, options);
         if (error)
             return json(class_type::null);
         consume_white_space(input, offset);
@@ -335,7 +365,8 @@ json parser::parse_null(const std::string& input, size_t& offset,
 }
 
 json parser::parse_next(const std::string& input, size_t& offset,
-                        std::error_code& error)
+                        std::error_code& error,
+                        const json::parse_options& options)
 {
     assert(!error);
     char value;
@@ -344,9 +375,9 @@ json parser::parse_next(const std::string& input, size_t& offset,
     switch (value)
     {
     case '[':
-        return parse_array(input, offset, error);
+        return parse_array(input, offset, error, options);
     case '{':
-        return parse_object(input, offset, error);
+        return parse_object(input, offset, error, options);
     case '\"':
         return parse_string(input, offset, error);
     case 't':
diff --git a/src/bourne/detail/parser.hpp b/src/bourne/detail/parser.hpp
index e8c2881c..673f5972 100644
--- a/src/bourne/detail/parser.hpp
+++ b/src/bourne/detail/parser.hpp
@@ -23,13 +23,20 @@ class parser
 public:
     static json parse(const std::string& input);
     static json parse(const std::string& input, std::error_code& error);
+    static json parse(const std::string& input,
+                      const json::parse_options& options);
+    static json parse(const std::string& input,
+                      const json::parse_options& options,
+                      std::error_code& error);
 
 private:
     static void consume_white_space(const std::string& input, size_t& offset);
     static json parse_object(const std::string& input, size_t& offset,
-                             std::error_code& error);
+                             std::error_code& error,
+                             const json::parse_options& options);
     static json parse_array(const std::string& input, size_t& offset,
-                            std::error_code& error);
+                            std::error_code& error,
+                            const json::parse_options& options);
     static json parse_string(const std::string& input, size_t& offset,
                              std::error_code& error);
     static json parse_number(const std::string& input, size_t& offset,
@@ -39,7 +46,8 @@ class parser
     static json parse_null(const std::string& input, size_t& offset,
                            std::error_code& error);
     static json parse_next(const std::string& input, size_t& offset,
-                           std::error_code& error);
+                           std::error_code& error,
+                           const json::parse_options& options);
 };
 }
 }
diff --git a/src/bourne/json.cpp b/src/bourne/json.cpp
index 32e69ab3..4396bd0d 100644
--- a/src/bourne/json.cpp
+++ b/src/bourne/json.cpp
@@ -537,12 +537,24 @@ bool json::contains(const json& other) const
 json json::parse(const std::string& input, std::error_code& error)
 {
     assert(!error);
-    return detail::parser::parse(input, error);
+    return detail::parser::parse(input, json::parse_options{}, error);
+}
+
+json json::parse(const std::string& input, const json::parse_options& options,
+                 std::error_code& error)
+{
+    assert(!error);
+    return detail::parser::parse(input, options, error);
 }
 
 json json::parse(const std::string& input)
 {
-    return detail::parser::parse(input);
+    return detail::parser::parse(input, json::parse_options{});
+}
+
+json json::parse(const std::string& input, const json::parse_options& options)
+{
+    return detail::parser::parse(input, options);
 }
 
 json json::array()
diff --git a/src/bourne/json.hpp b/src/bourne/json.hpp
index a159e94f..4ffbff91 100644
--- a/src/bourne/json.hpp
+++ b/src/bourne/json.hpp
@@ -49,6 +49,15 @@ class json
     using array_type = detail::backing_data::array_type;
 
 public:
+    struct parse_options
+    {
+        /// Enable strict JSON parsing checks.
+        ///
+        /// Currently this enables:
+        /// - bourne::error::parse_object_duplicate_key
+        bool strict = false;
+    };
+
     /// Default constructor, creates a null value.
     json();
 
@@ -343,9 +352,16 @@ class json
     /// Parse a string as a json object.
     static json parse(const std::string& input, std::error_code& error);
 
+    /// Parse a string as a json object with options.
+    static json parse(const std::string& input, const parse_options& options,
+                      std::error_code& error);
+
     /// Parse a string as a json object.
     static json parse(const std::string& input);
 
+    /// Parse a string as a json object with options.
+    static json parse(const std::string& input, const parse_options& options);
+
     /// Create a json array
     static json array();
     template <typename... T>
diff --git a/test/src/test_parser.cpp b/test/src/test_parser.cpp
index dd2e2890..e4f85acd 100644
--- a/test/src/test_parser.cpp
+++ b/test/src/test_parser.cpp
@@ -6,6 +6,7 @@
 #include <fstream>
 
 #include <bourne/detail/parser.hpp>
+#include <bourne/json.hpp>
 #include <gtest/gtest.h>
 
 namespace
@@ -212,3 +213,44 @@ TEST(test_parser, test_parse_unicode)
     ASSERT_FALSE((bool)error);
     ASSERT_EQ(json_string, result.dump_min());
 }
+
+TEST(test_parser, test_parse_object_duplicate_key_non_strict)
+{
+    std::error_code error;
+    std::string json_string = "{\"bourne\":1,\"bourne\":2}";
+    auto result = bourne::detail::parser::parse(json_string, error);
+
+    ASSERT_FALSE((bool)error);
+    ASSERT_TRUE(result.is_object());
+    ASSERT_TRUE(result.has_key("bourne"));
+    EXPECT_EQ(2, result["bourne"].to_int());
+}
+
+TEST(test_parser, test_parse_object_duplicate_key_strict)
+{
+    std::error_code error;
+    std::string json_string = "{\"bourne\":1,\"bourne\":2}";
+    bourne::json::parse_options options;
+    options.strict = true;
+
+    auto result = bourne::detail::parser::parse(json_string, options, error);
+
+    EXPECT_EQ(bourne::error::parse_object_duplicate_key, error)
+        << error.message();
+    ASSERT_EQ(bourne::json::null(), result);
+}
+
+TEST(test_parser, test_parse_nested_object_duplicate_key_strict)
+{
+    std::error_code error;
+    std::string json_string =
+        "{\"outer\":{\"bourne\":1,\"bourne\":2},\"ok\":true}";
+    bourne::json::parse_options options;
+    options.strict = true;
+
+    auto result = bourne::json::parse(json_string, options, error);
+
+    EXPECT_EQ(bourne::error::parse_object_duplicate_key, error)
+        << error.message();
+    ASSERT_EQ(bourne::json::null(), result);
+}