diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 8e763de5..23a80316 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -2,9 +2,9 @@ name: CI
 
 on:
   push:
-    branches: [ master ]
+    branches: [master]
   pull_request:
-    branches: [ '**' ]
+    branches: ["**"]
 
 env:
   RACK_ENV: development
@@ -24,7 +24,6 @@ jobs:
       fail-fast: false
       matrix:
         ruby:
-          - "2.3"
           - "2.4"
           - "2.5"
           - "2.6"
@@ -32,24 +31,28 @@ jobs:
           - "3.0"
           - "3.1"
           - "3.2"
+          - "3.3"
           - "jruby-9.4"
+        rack:
+          - "2"
+          - "3"
 
     steps:
-    - uses: actions/checkout@v3
+      - uses: actions/checkout@v3
 
-    - name: Set up Ruby
-      uses: ruby/setup-ruby@v1
-      with:
-        ruby-version: ${{ matrix.ruby }}
-        bundler-cache: true
-        rubygems: ${{ matrix.ruby <= '2.5' && '3.3.26' || 'latest' }}
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          bundler-cache: true
+          rubygems: ${{ matrix.ruby <= '2.5' && '3.3.26' || 'latest' }}
 
-    - name: Set up Minio
-      run: |
-        mkdir -p "${GITHUB_WORKSPACE}"/minio/data/minio-bucket
-        wget -nc -O "${GITHUB_WORKSPACE}"/minio/minio https://dl.min.io/server/minio/release/linux-amd64/minio
-        chmod +x "${GITHUB_WORKSPACE}"/minio/minio
-        ${GITHUB_WORKSPACE}/minio/minio server ${GITHUB_WORKSPACE}/minio/data --address localhost:9000 &>${GITHUB_WORKSPACE}/minio/data/server.log &
+      - name: Set up Minio
+        run: |
+          mkdir -p "${GITHUB_WORKSPACE}"/minio/data/minio-bucket
+          wget -nc -O "${GITHUB_WORKSPACE}"/minio/minio https://dl.min.io/server/minio/release/linux-amd64/minio
+          chmod +x "${GITHUB_WORKSPACE}"/minio/minio
+          ${GITHUB_WORKSPACE}/minio/minio server ${GITHUB_WORKSPACE}/minio/data --address localhost:9000 &>${GITHUB_WORKSPACE}/minio/data/server.log &
 
-    - name: Run tests
-      run: bundle exec rake test
+      - name: Run tests
+        run: bundle exec appraisal rack-${{ matrix.rack }} rake test
diff --git a/Appraisals b/Appraisals
new file mode 100644
index 00000000..f5b330cf
--- /dev/null
+++ b/Appraisals
@@ -0,0 +1,7 @@
+appraise "rack-2" do
+  gem "rack", "~> 2"
+end
+
+appraise "rack-3" do
+  gem "rack", "~> 3"
+end
diff --git a/gemfiles/rack_2.gemfile b/gemfiles/rack_2.gemfile
new file mode 100644
index 00000000..0b47a3a3
--- /dev/null
+++ b/gemfiles/rack_2.gemfile
@@ -0,0 +1,10 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "pry"
+gem "simplecov"
+gem "hanna", require: false
+gem "rack", "~> 2"
+
+gemspec path: "../"
diff --git a/gemfiles/rack_2.gemfile.lock b/gemfiles/rack_2.gemfile.lock
new file mode 100644
index 00000000..c74a7331
--- /dev/null
+++ b/gemfiles/rack_2.gemfile.lock
@@ -0,0 +1,161 @@
+PATH
+  remote: ..
+  specs:
+    shrine (3.5.0)
+      content_disposition (~> 1.0)
+      down (~> 5.1)
+
+GEM
+  remote: https://rubygems.org/
+  specs:
+    activemodel (7.1.3.2)
+      activesupport (= 7.1.3.2)
+    activerecord (7.1.3.2)
+      activemodel (= 7.1.3.2)
+      activesupport (= 7.1.3.2)
+      timeout (>= 0.4.0)
+    activesupport (7.1.3.2)
+      base64
+      bigdecimal
+      concurrent-ruby (~> 1.0, >= 1.0.2)
+      connection_pool (>= 2.2.5)
+      drb
+      i18n (>= 1.6, < 2)
+      minitest (>= 5.1)
+      mutex_m
+      tzinfo (~> 2.0)
+    addressable (2.8.6)
+      public_suffix (>= 2.0.2, < 6.0)
+    appraisal (2.5.0)
+      bundler
+      rake
+      thor (>= 0.14.0)
+    aws-eventstream (1.3.0)
+    aws-partitions (1.904.0)
+    aws-sdk-core (3.191.5)
+      aws-eventstream (~> 1, >= 1.3.0)
+      aws-partitions (~> 1, >= 1.651.0)
+      aws-sigv4 (~> 1.8)
+      jmespath (~> 1, >= 1.6.1)
+    aws-sdk-kms (1.78.0)
+      aws-sdk-core (~> 3, >= 3.191.0)
+      aws-sigv4 (~> 1.1)
+    aws-sdk-s3 (1.146.1)
+      aws-sdk-core (~> 3, >= 3.191.0)
+      aws-sdk-kms (~> 1)
+      aws-sigv4 (~> 1.8)
+    aws-sigv4 (1.8.0)
+      aws-eventstream (~> 1, >= 1.0.2)
+    base64 (0.2.0)
+    bigdecimal (3.1.7)
+    coderay (1.1.3)
+    concurrent-ruby (1.2.3)
+    connection_pool (2.4.1)
+    content_disposition (1.0.0)
+    docile (1.4.0)
+    down (5.4.1)
+      addressable (~> 2.8)
+    drb (2.2.1)
+    dry-configurable (1.1.0)
+      dry-core (~> 1.0, < 2)
+      zeitwerk (~> 2.6)
+    dry-core (1.0.1)
+      concurrent-ruby (~> 1.0)
+      zeitwerk (~> 2.6)
+    dry-events (1.0.1)
+      concurrent-ruby (~> 1.0)
+      dry-core (~> 1.0, < 2)
+    dry-monitor (1.0.1)
+      dry-configurable (~> 1.0, < 2)
+      dry-core (~> 1.0, < 2)
+      dry-events (~> 1.0, < 2)
+    fastimage (2.3.0)
+    ffi (1.16.3)
+    hanna (1.5.0)
+      rdoc (>= 4)
+    http-form_data (2.3.0)
+    i18n (1.14.4)
+      concurrent-ruby (~> 1.0)
+    jmespath (1.6.2)
+    marcel (1.0.4)
+    method_source (1.0.0)
+    mime-types (3.5.2)
+      mime-types-data (~> 3.2015)
+    mime-types-data (3.2024.0305)
+    mimemagic (0.4.3)
+      nokogiri (~> 1)
+      rake
+    mini_magick (4.12.0)
+    mini_mime (1.1.5)
+    minitest (5.22.3)
+    mocha (1.16.1)
+    mutex_m (0.2.0)
+    nokogiri (1.16.3-arm64-darwin)
+      racc (~> 1.4)
+    pry (0.14.2)
+      coderay (~> 1.1)
+      method_source (~> 1.0)
+    psych (5.1.2)
+      stringio
+    public_suffix (5.0.4)
+    racc (1.7.3)
+    rack (2.2.9)
+    rack-test_app (1.1.0)
+      rack
+    rake (13.1.0)
+    rdoc (6.6.3.1)
+      psych (>= 4.0.0)
+    rexml (3.2.6)
+    ruby-filemagic (0.7.3)
+    ruby-vips (2.2.1)
+      ffi (~> 1.12)
+    sequel (5.78.0)
+      bigdecimal
+    simplecov (0.22.0)
+      docile (~> 1.1)
+      simplecov-html (~> 0.11)
+      simplecov_json_formatter (~> 0.1)
+    simplecov-html (0.12.3)
+    simplecov_json_formatter (0.1.4)
+    sqlite3 (1.7.3-arm64-darwin)
+    stringio (3.1.0)
+    thor (1.3.1)
+    timeout (0.4.1)
+    tzinfo (2.0.6)
+      concurrent-ruby (~> 1.0)
+    zeitwerk (2.6.13)
+
+PLATFORMS
+  arm64-darwin
+
+DEPENDENCIES
+  activerecord (~> 7.0)
+  activesupport (~> 7.0)
+  appraisal (~> 2.5)
+  aws-sdk-core (~> 3.23)
+  aws-sdk-s3 (~> 1.69)
+  dry-monitor
+  fastimage
+  hanna
+  http-form_data (~> 2.2)
+  marcel
+  mime-types
+  mimemagic (>= 0.3.2)
+  mini_magick (~> 4.0)
+  mini_mime (~> 1.0)
+  minitest (~> 5.8)
+  mocha (~> 1.11)
+  pry
+  rack (~> 2)
+  rack-test_app
+  rake (>= 11.1)
+  rexml
+  ruby-filemagic (~> 0.7)
+  ruby-vips (~> 2.0)
+  sequel
+  shrine!
+  simplecov
+  sqlite3 (~> 1.4)
+
+BUNDLED WITH
+   2.5.4
diff --git a/gemfiles/rack_3.gemfile b/gemfiles/rack_3.gemfile
new file mode 100644
index 00000000..c3394c64
--- /dev/null
+++ b/gemfiles/rack_3.gemfile
@@ -0,0 +1,10 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "pry"
+gem "simplecov"
+gem "hanna", require: false
+gem "rack", "~> 3"
+
+gemspec path: "../"
diff --git a/gemfiles/rack_3.gemfile.lock b/gemfiles/rack_3.gemfile.lock
new file mode 100644
index 00000000..8276eed9
--- /dev/null
+++ b/gemfiles/rack_3.gemfile.lock
@@ -0,0 +1,161 @@
+PATH
+  remote: ..
+  specs:
+    shrine (3.5.0)
+      content_disposition (~> 1.0)
+      down (~> 5.1)
+
+GEM
+  remote: https://rubygems.org/
+  specs:
+    activemodel (7.1.3.2)
+      activesupport (= 7.1.3.2)
+    activerecord (7.1.3.2)
+      activemodel (= 7.1.3.2)
+      activesupport (= 7.1.3.2)
+      timeout (>= 0.4.0)
+    activesupport (7.1.3.2)
+      base64
+      bigdecimal
+      concurrent-ruby (~> 1.0, >= 1.0.2)
+      connection_pool (>= 2.2.5)
+      drb
+      i18n (>= 1.6, < 2)
+      minitest (>= 5.1)
+      mutex_m
+      tzinfo (~> 2.0)
+    addressable (2.8.6)
+      public_suffix (>= 2.0.2, < 6.0)
+    appraisal (2.5.0)
+      bundler
+      rake
+      thor (>= 0.14.0)
+    aws-eventstream (1.3.0)
+    aws-partitions (1.904.0)
+    aws-sdk-core (3.191.5)
+      aws-eventstream (~> 1, >= 1.3.0)
+      aws-partitions (~> 1, >= 1.651.0)
+      aws-sigv4 (~> 1.8)
+      jmespath (~> 1, >= 1.6.1)
+    aws-sdk-kms (1.78.0)
+      aws-sdk-core (~> 3, >= 3.191.0)
+      aws-sigv4 (~> 1.1)
+    aws-sdk-s3 (1.146.1)
+      aws-sdk-core (~> 3, >= 3.191.0)
+      aws-sdk-kms (~> 1)
+      aws-sigv4 (~> 1.8)
+    aws-sigv4 (1.8.0)
+      aws-eventstream (~> 1, >= 1.0.2)
+    base64 (0.2.0)
+    bigdecimal (3.1.7)
+    coderay (1.1.3)
+    concurrent-ruby (1.2.3)
+    connection_pool (2.4.1)
+    content_disposition (1.0.0)
+    docile (1.4.0)
+    down (5.4.1)
+      addressable (~> 2.8)
+    drb (2.2.1)
+    dry-configurable (1.1.0)
+      dry-core (~> 1.0, < 2)
+      zeitwerk (~> 2.6)
+    dry-core (1.0.1)
+      concurrent-ruby (~> 1.0)
+      zeitwerk (~> 2.6)
+    dry-events (1.0.1)
+      concurrent-ruby (~> 1.0)
+      dry-core (~> 1.0, < 2)
+    dry-monitor (1.0.1)
+      dry-configurable (~> 1.0, < 2)
+      dry-core (~> 1.0, < 2)
+      dry-events (~> 1.0, < 2)
+    fastimage (2.3.0)
+    ffi (1.16.3)
+    hanna (1.5.0)
+      rdoc (>= 4)
+    http-form_data (2.3.0)
+    i18n (1.14.4)
+      concurrent-ruby (~> 1.0)
+    jmespath (1.6.2)
+    marcel (1.0.4)
+    method_source (1.0.0)
+    mime-types (3.5.2)
+      mime-types-data (~> 3.2015)
+    mime-types-data (3.2024.0305)
+    mimemagic (0.4.3)
+      nokogiri (~> 1)
+      rake
+    mini_magick (4.12.0)
+    mini_mime (1.1.5)
+    minitest (5.22.3)
+    mocha (1.16.1)
+    mutex_m (0.2.0)
+    nokogiri (1.16.3-arm64-darwin)
+      racc (~> 1.4)
+    pry (0.14.2)
+      coderay (~> 1.1)
+      method_source (~> 1.0)
+    psych (5.1.2)
+      stringio
+    public_suffix (5.0.4)
+    racc (1.7.3)
+    rack (3.0.10)
+    rack-test_app (1.1.0)
+      rack
+    rake (13.1.0)
+    rdoc (6.6.3.1)
+      psych (>= 4.0.0)
+    rexml (3.2.6)
+    ruby-filemagic (0.7.3)
+    ruby-vips (2.2.1)
+      ffi (~> 1.12)
+    sequel (5.78.0)
+      bigdecimal
+    simplecov (0.22.0)
+      docile (~> 1.1)
+      simplecov-html (~> 0.11)
+      simplecov_json_formatter (~> 0.1)
+    simplecov-html (0.12.3)
+    simplecov_json_formatter (0.1.4)
+    sqlite3 (1.7.3-arm64-darwin)
+    stringio (3.1.0)
+    thor (1.3.1)
+    timeout (0.4.1)
+    tzinfo (2.0.6)
+      concurrent-ruby (~> 1.0)
+    zeitwerk (2.6.13)
+
+PLATFORMS
+  arm64-darwin
+
+DEPENDENCIES
+  activerecord (~> 7.0)
+  activesupport (~> 7.0)
+  appraisal (~> 2.5)
+  aws-sdk-core (~> 3.23)
+  aws-sdk-s3 (~> 1.69)
+  dry-monitor
+  fastimage
+  hanna
+  http-form_data (~> 2.2)
+  marcel
+  mime-types
+  mimemagic (>= 0.3.2)
+  mini_magick (~> 4.0)
+  mini_mime (~> 1.0)
+  minitest (~> 5.8)
+  mocha (~> 1.11)
+  pry
+  rack (~> 3)
+  rack-test_app
+  rake (>= 11.1)
+  rexml
+  ruby-filemagic (~> 0.7)
+  ruby-vips (~> 2.0)
+  sequel
+  shrine!
+  simplecov
+  sqlite3 (~> 1.4)
+
+BUNDLED WITH
+   2.5.4
diff --git a/shrine.gemspec b/shrine.gemspec
index 5c2c3a36..26912822 100644
--- a/shrine.gemspec
+++ b/shrine.gemspec
@@ -37,6 +37,7 @@ direct uploads for fully asynchronous user experience.
   gem.add_dependency "content_disposition", "~> 1.0"
 
   # general testing helpers
+  gem.add_development_dependency "appraisal", "~> 2.5"
   gem.add_development_dependency "rake", ">= 11.1"
   gem.add_development_dependency "minitest", "~> 5.8"
   gem.add_development_dependency "mocha", "~> 1.11"