diff --git a/.github/workflows/test.yaml b/.github/workflows/test.yaml
new file mode 100644
index 0000000..0253de1
--- /dev/null
+++ b/.github/workflows/test.yaml
@@ -0,0 +1,25 @@
+name: Test
+
+on: [push, pull_request]
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby:
+          - '3.3'
+          - '3.4'
+          - '4.0'
+          - ruby-head
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
+    - uses: ruby/setup-ruby@6e5d382445ae5590b7449d8b3bc8cb1c2c27f617 # v1.317.0
+      with:
+        ruby-version: ${{matrix.ruby}}
+        bundler-cache: true
+    - run: bundle exec rake
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..058471b
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+/Gemfile.lock
+/pkg/
+/*.gem
diff --git a/Gemfile b/Gemfile
new file mode 100644
index 0000000..be173b2
--- /dev/null
+++ b/Gemfile
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+source "https://rubygems.org"
+
+gemspec
diff --git a/Rakefile b/Rakefile
new file mode 100644
index 0000000..56237d2
--- /dev/null
+++ b/Rakefile
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+require "bundler/gem_tasks"
+require "rake/testtask"
+
+Rake::TestTask.new(:test) do |t|
+  t.libs << "test"
+  t.test_files = FileList["test/test_*.rb"]
+end
+
+task default: :test
diff --git a/lib/nack.rb b/lib/nack.rb
new file mode 100644
index 0000000..598cf7b
--- /dev/null
+++ b/lib/nack.rb
@@ -0,0 +1,3 @@
+# frozen_string_literal: true
+
+require_relative "nack/version"
diff --git a/lib/nack/version.rb b/lib/nack/version.rb
new file mode 100644
index 0000000..0cd460a
--- /dev/null
+++ b/lib/nack/version.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+module Nack
+  VERSION = "0.1.0"
+end
diff --git a/nack.gemspec b/nack.gemspec
new file mode 100644
index 0000000..3bd56d3
--- /dev/null
+++ b/nack.gemspec
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require_relative "lib/nack/version"
+
+Gem::Specification.new do |spec|
+  spec.name = "nack"
+  spec.version = Nack::VERSION
+  spec.summary = "Ruby toolkit for NSGI applications"
+  spec.description = <<~DESCRIPTION
+    Middleware with a composition DSL, request/response conveniences,
+    path-based dispatch, and a host-free test kit for applications
+    targeting the NSGI Ruby application contract.
+  DESCRIPTION
+  spec.authors = ["himura467"]
+  spec.homepage = "https://github.com/nsgi-org/nack-ruby"
+  spec.license = "MIT"
+  spec.required_ruby_version = ">= 3.3"
+
+  spec.metadata = {
+    "source_code_uri" => "https://github.com/nsgi-org/nack-ruby",
+    "bug_tracker_uri" => "https://github.com/nsgi-org/nack-ruby/issues",
+    "rubygems_mfa_required" => "true"
+  }
+
+  spec.files = Dir["lib/**/*.rb", "README.md", "LICENSE"]
+  spec.require_paths = ["lib"]
+
+  spec.add_development_dependency "bundler"
+  spec.add_development_dependency "rake"
+  spec.add_development_dependency "minitest"
+end
diff --git a/test/helper.rb b/test/helper.rb
new file mode 100644
index 0000000..2e49dfb
--- /dev/null
+++ b/test/helper.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+$LOAD_PATH.unshift(File.expand_path("../lib", __dir__))
+
+require "nack"
+require "minitest/autorun"