diff --git a/.github/workflows/rubocop.yml b/.github/workflows/rubocop.yml
index 93436de..3c13171 100644
--- a/.github/workflows/rubocop.yml
+++ b/.github/workflows/rubocop.yml
@@ -3,6 +3,8 @@ on: [push, pull_request]
 jobs:
   lint:
     runs-on: ubuntu-latest
+    env:
+      BUNDLE_GEMFILE: gemfiles/rubocop.gemfile
     steps:
       - uses: actions/checkout@v7
       - name: Set up Ruby
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 5e9e543..6f4462e 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -14,6 +14,19 @@ jobs:
           - "4.0"
           - "jruby-9.4"
           - "jruby-10"
+        gemfile:
+          - Gemfile
+        include:
+          # See https://github.com/dblock/strava-ruby-client/issues/113: json
+          # 2.x is the version this gem currently supports. json_3 is
+          # commented out until Faraday's :json middleware supports json >=
+          # 3.0, since it currently fails (Faraday::ParsingError).
+          - ruby-version: "3.4"
+            gemfile: gemfiles/json_2.gemfile
+          # - ruby-version: "3.4"
+          #   gemfile: gemfiles/json_3.gemfile
+    env:
+      BUNDLE_GEMFILE: ${{ matrix.gemfile }}
     steps:
       - uses: actions/checkout@v7
       - name: Set up Ruby
@@ -31,7 +44,7 @@ jobs:
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
           path-to-lcov: coverage/lcov.info
-          flag-name: ${{ matrix.ruby-version }}
+          flag-name: ${{ matrix.gemfile == 'Gemfile' && matrix.ruby-version || format('{0}-{1}', matrix.ruby-version, matrix.gemfile) }}
           parallel: true
   integration:
     runs-on: ubuntu-latest
diff --git a/.gitignore b/.gitignore
index 6f68543..07768c8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,5 +6,6 @@
 .tool-versions
 .vscode
 Gemfile.lock
+gemfiles/*.gemfile.lock
 pkg
 coverage
diff --git a/.rubocop.yml b/.rubocop.yml
index eb92522..643c84e 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -9,6 +9,7 @@ AllCops:
   NewCops: enable
   Exclude:
     - vendor/**/*
+    - gemfiles/**/*
 
 Naming/MethodName:
   Enabled: false
diff --git a/Appraisals b/Appraisals
new file mode 100644
index 0000000..f04553b
--- /dev/null
+++ b/Appraisals
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+# Tests the gem against the two major json releases that are relevant to
+# https://github.com/dblock/strava-ruby-client/issues/113: json < 3.0, where
+# JSON.parse accepts a positional options hash (the form Faraday's :json
+# response middleware uses), and json >= 3.0, where JSON.parse only accepts
+# keyword arguments and Faraday's call raises an ArgumentError.
+appraise 'json-2' do
+  gem 'json', '~> 2.3'
+end
+
+appraise 'json-3' do
+  gem 'json', '~> 3.0'
+end
diff --git a/CHANGELOG.md b/CHANGELOG.md
index efb2546..36a6601 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,6 @@
 ### 3.1.1 (Next)
 
+* [#113](https://github.com/dblock/strava-ruby-client/issues/113): Adds Appraisals (`json-2`, `json-3`) - [@dblock](https://github.com/dblock).
 * Your contribution here.
 
 ### 3.1.0 (2026/08/29)
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 8ee278c..660f7ca 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -25,6 +25,26 @@ bundle install
 bundle exec rake
 ```
 
+Rubocop uses its own `gemfiles/rubocop.gemfile`, kept separate so its pinned version doesn't constrain the main Gemfile's dependency resolution.
+
+```
+BUNDLE_GEMFILE=gemfiles/rubocop.gemfile bundle install
+BUNDLE_GEMFILE=gemfiles/rubocop.gemfile bundle exec rubocop
+```
+
+This gem is tested against multiple `json` gem versions using [Appraisal](https://github.com/thoughtbot/appraisal), defined in `Appraisals`. To run the test suite against a specific `json` version, e.g. to reproduce [#113](https://github.com/dblock/strava-ruby-client/issues/113):
+
+```
+BUNDLE_GEMFILE=gemfiles/json_3.gemfile bundle install
+BUNDLE_GEMFILE=gemfiles/json_3.gemfile bundle exec rake spec
+```
+
+If you add or change a runtime/test dependency in the main `Gemfile`, regenerate the appraisal gemfiles.
+
+```
+bundle exec appraisal generate
+```
+
 ## Contribute Code
 
 ### Obtain a Strava Token
diff --git a/Gemfile b/Gemfile
index d3f59ce..3bbd50f 100755
--- a/Gemfile
+++ b/Gemfile
@@ -4,7 +4,14 @@ source 'http://rubygems.org'
 
 gemspec
 
+# Faraday's :json response middleware is incompatible with json >= 3.0 (see
+# https://github.com/dblock/strava-ruby-client/issues/113), so pin json here
+# rather than relying on rubocop's own transitive constraint. The `json-3`
+# appraisal (see Appraisals) is used to track when this can be removed.
+gem 'json', '~> 2.3'
+
 group :development, :test do
+  gem 'appraisal'
   gem 'csv'
   gem 'danger-changelog', '~> 0.8.0'
   gem 'danger-pr-comment'
@@ -17,9 +24,6 @@ group :development, :test do
   gem 'pry'
   gem 'rake'
   gem 'rspec'
-  gem 'rubocop', '1.68.0'
-  gem 'rubocop-rake'
-  gem 'rubocop-rspec'
   gem 'tcx'
   gem 'vcr'
   gem 'webmock'
diff --git a/Rakefile b/Rakefile
index cd00c82..418ac7d 100644
--- a/Rakefile
+++ b/Rakefile
@@ -17,7 +17,9 @@ RSpec::Core::RakeTask.new(:'spec:integration') do |spec|
   spec.pattern = FileList['spec/integration/**/*_spec.rb']
 end
 
-require 'rubocop/rake_task'
-RuboCop::RakeTask.new
+# Rubocop lives in its own Gemfile (gemfiles/rubocop.gemfile), not the main
+# Gemfile, so it doesn't constrain dependency resolution there (see
+# https://github.com/dblock/strava-ruby-client/issues/113). Run it with
+# `BUNDLE_GEMFILE=gemfiles/rubocop.gemfile bundle exec rubocop`.
 
-task default: %i[rubocop spec]
+task default: %i[spec]
diff --git a/gemfiles/json_2.gemfile b/gemfiles/json_2.gemfile
new file mode 100644
index 0000000..f4c3695
--- /dev/null
+++ b/gemfiles/json_2.gemfile
@@ -0,0 +1,32 @@
+# This file was generated by Appraisal
+
+source "http://rubygems.org"
+
+gem "json", "~> 2.3"
+
+group :development, :test do
+  gem "appraisal"
+  gem "csv"
+  gem "danger-changelog", "~> 0.8.0"
+  gem "danger-pr-comment"
+  gem "danger-toc", "~> 0.2.0"
+  gem "dotenv"
+  gem "faraday-retry"
+  gem "gpx"
+  gem "multi_xml"
+  gem "polylines"
+  gem "pry"
+  gem "rake"
+  gem "rspec"
+  gem "tcx"
+  gem "vcr"
+  gem "webmock"
+  gem "webrick", "~> 1.9"
+end
+
+group :test do
+  gem "simplecov"
+  gem "simplecov-lcov", require: false
+end
+
+gemspec path: "../"
diff --git a/gemfiles/json_3.gemfile b/gemfiles/json_3.gemfile
new file mode 100644
index 0000000..503edea
--- /dev/null
+++ b/gemfiles/json_3.gemfile
@@ -0,0 +1,32 @@
+# This file was generated by Appraisal
+
+source "http://rubygems.org"
+
+gem "json", "~> 3.0"
+
+group :development, :test do
+  gem "appraisal"
+  gem "csv"
+  gem "danger-changelog", "~> 0.8.0"
+  gem "danger-pr-comment"
+  gem "danger-toc", "~> 0.2.0"
+  gem "dotenv"
+  gem "faraday-retry"
+  gem "gpx"
+  gem "multi_xml"
+  gem "polylines"
+  gem "pry"
+  gem "rake"
+  gem "rspec"
+  gem "tcx"
+  gem "vcr"
+  gem "webmock"
+  gem "webrick", "~> 1.9"
+end
+
+group :test do
+  gem "simplecov"
+  gem "simplecov-lcov", require: false
+end
+
+gemspec path: "../"
diff --git a/gemfiles/rubocop.gemfile b/gemfiles/rubocop.gemfile
new file mode 100644
index 0000000..271c7f3
--- /dev/null
+++ b/gemfiles/rubocop.gemfile
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+# Rubocop is kept in its own Gemfile, separate from the main Gemfile, so that
+# its exact pinned version (and its own transitive dependency constraints,
+# e.g. on json) don't participate in dependency resolution for the gem's
+# runtime/test Gemfile or its Appraisals. See
+# https://github.com/dblock/strava-ruby-client/issues/113.
+
+source 'http://rubygems.org'
+
+gem 'rubocop', '1.68.0'
+gem 'rubocop-rake'
+gem 'rubocop-rspec'