diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 9283808f..dd6c2d41 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -10,39 +10,14 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        include:
-          - ruby: '3.2'
-            rails: '7.2.2.2'
-            grape: '~> 1.8.0'
-            grape-swagger: '1.6.1'
-          - ruby: '3.2'
-            rails: '7.2.2.2'
-            grape: '~> 3.1.0'
-            grape-swagger: '2.1.4'
-          - ruby: '3.3'
-            rails: '7.2.2.2'
-            grape: '~> 3.1.0'
-            grape-swagger: '2.1.4'
-          - ruby: '3.4'
-            rails: '7.2.2.2'
-            grape: '~> 3.1.0'
-            grape-swagger: '2.1.4'
-          - ruby: '3.2'
-            rails: '~> 8.1.3'
-            grape: '~> 3.1.0'
-            grape-swagger: '2.1.4'
-          - ruby: '3.3'
-            rails: '~> 8.1.3'
-            grape: '~> 3.1.0'
-            grape-swagger: '2.1.4'
-          - ruby: '3.4'
-            rails: '~> 8.1.3'
-            grape: '~> 3.1.0'
-            grape-swagger: '2.1.4'
+        ruby: ['3.2', '3.3', '3.4']
+        rails: ['~> 8.1.4']
+        json: ['~> 2.0', '~> 3.0']
     env:
-      GRAPE_VERSION: ${{ matrix.grape }}
-      GRAPE_SWAGGER_VERSION: ${{ matrix.grape-swagger }}
+      GRAPE_VERSION: '~> 3.1.0'
+      GRAPE_SWAGGER_VERSION: '2.1.4'
       RAILS_VERSION: ${{ matrix.rails }}
+      JSON_VERSION: ${{ matrix.json }}
     steps:
       - uses: actions/checkout@v6
       - name: Set up Ruby
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0888a63b..23b6f100 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,6 @@
 ### Next Release
 
+* [#179](https://github.com/ruby-grape/grape-swagger-rails/pull/179): Require Rails 8.1.4+ and allow JSON 3 - [@moskvin](https://github.com/moskvin).
 * Your contribution here.
 
 ### 1.0.10 (2026/09/22)
diff --git a/CLAUDE.md b/CLAUDE.md
index b622ccbf..54a0429f 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -73,8 +73,7 @@ Config in `.rubocop.yml` targets Ruby 3.4. Plugins: rubocop-capybara, rubocop-rs
 
 ## Compatibility Matrix
 
-- Rails 7.2 / 8.1 × Ruby 3.2–3.4 × grape-swagger 2.1.4 (grape ~> 3.1)
-- Rails 7.2 × Ruby 3.2 × grape-swagger 1.6.1 (grape ~> 1.8) — legacy combination
+- Rails 8.1.4–8.1.x × Ruby 3.2–3.4 × JSON 2/3 × grape-swagger 2.1.4 (grape ~> 3.1)
 - Ruby 3.1 is excluded from Rails 8 (requires 3.2+)
 - grape ~> 1.8 is not tested on Ruby 3.4: Ruby 3.4 tightened `Forwardable` to raise on private-method delegation, which breaks Mustermann's `named_captures` forwarding used by grape-swagger 1.6.1 to introspect routes
 - Both Sprockets and Propshaft asset pipelines are tested in CI
diff --git a/Gemfile b/Gemfile
index 0b469b48..0a1604a5 100644
--- a/Gemfile
+++ b/Gemfile
@@ -18,13 +18,15 @@ else
   gem 'grape-swagger', grape_swagger_version
 end
 
-case rails_version = ENV.fetch('RAILS_VERSION', '>= 7.2.3.1')
+case rails_version = ENV.fetch('RAILS_VERSION', '>= 8.1.4')
 when 'edge'
   gem 'railties', github: 'rails/rails', branch: 'main'
 else
   gem 'railties', rails_version
 end
 
+gem 'json', ENV.fetch('JSON_VERSION') if ENV.key?('JSON_VERSION')
+
 group :development, :test do
   gem 'capybara'
   gem 'danger', require: false
diff --git a/README.md b/README.md
index 39ce2b44..95b84389 100644
--- a/README.md
+++ b/README.md
@@ -44,13 +44,12 @@ Or install it yourself as:
 
 This gem is continuously tested against the following stack:
 
-| Ruby | Rails   | Grape   | grape-swagger | Swagger UI |
-|-----:|--------:|--------:|--------------:|-----------:|
-| 3.4  | 7.2.2.2 | 1.8.x   | 1.6.1         | 5.33.0     |
-| 3.2+ | 7.2.2.2 | 3.1.x   | 2.1.4         | 5.33.0     |
-| 3.2+ | 8.1.x   | 3.1.x   | 2.1.4         | 5.33.0     |
+| Ruby | Rails  | JSON    | Grape | grape-swagger | Swagger UI |
+|-----:|-------:|--------:|------:|--------------:|-----------:|
+| 3.2+ | 8.1.4–8.1.x | 2.x/3.x | 3.1.x | 2.1.4         | 5.33.0     |
 
 The dummy app and CI also exercise both supported Rails asset pipelines: Sprockets and Propshaft.
+Rails 8.1.4 is required for JSON 3 compatibility; older Rails versions remain supported by the 1.x gem releases.
 
 If you use a nearby version and hit an issue, please open one with your `Gemfile.lock` and a minimal reproduction.
 
diff --git a/grape-swagger-rails.gemspec b/grape-swagger-rails.gemspec
index 6ebdb0e6..124fe40d 100644
--- a/grape-swagger-rails.gemspec
+++ b/grape-swagger-rails.gemspec
@@ -18,10 +18,9 @@ Gem::Specification.new do |spec|
   spec.require_paths = %w[lib]
   spec.required_ruby_version = '>= 3.2'
   spec.add_dependency 'haml-rails', '>= 2.0', '< 4.0'
-  # Supported Rails versions use JSON APIs removed in JSON 3 (quirks_mode and positional parse options).
-  spec.add_dependency 'json', '>= 2.0', '< 3.0'
+  spec.add_dependency 'json', '>= 2.0'
   spec.add_dependency 'ostruct', '>= 0.6', '< 1.0'
-  spec.add_dependency 'railties', '>= 7.2.2.2', '< 8.2'
+  spec.add_dependency 'railties', '>= 8.1.4', '< 8.2'
   spec.metadata = {
     'bug_tracker_uri' => 'https://github.com/ruby-grape/grape-swagger-rails/issues',
     'changelog_uri' => 'https://github.com/ruby-grape/grape-swagger-rails/blob/master/CHANGELOG.md',