diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..a91e7ed
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,60 @@
+name: CI
+on:
+  push:
+    branches:
+      - '**'
+    tags-ignore:
+      - '**'
+    paths:
+      - '**/*.swift'
+      - '.github/workflows/*.yml'
+  pull_request:
+    paths:
+      - '**/*.swift'
+      - '.github/workflows/*.yml'
+jobs:
+  test:
+    strategy:
+      matrix:
+        os:
+          - ubuntu-latest
+          - macOS-latest
+        swift-compat-ver:
+          - '5'
+          # - '4.2'
+          # - '4'
+    runs-on: ${{ matrix.os }}
+    steps:
+    - uses: actions/checkout@v2
+    - name: Use a cache for ".build" directory.
+      uses: actions/cache@v1
+      with:
+        path: .build
+        key: build-${{ github.workspace }}-${{ runner.os }}-${{ matrix.swift-compat-ver }}-${{ hashFiles('**/*.swift') }}
+        restore-keys: |
+          build-${{ github.workspace }}-${{ runner.os }}-${{ matrix.swift-compat-ver }}-
+          build-${{ github.workspace }}-${{ runner.os }}-
+          build-${{ github.workspace }}-
+    - uses: YOCKOW/Action-setup-swift@master
+      with:
+        swift-version: '5.2.2'
+    - name: Try to build products with debug mode.
+      run: |
+        swift build --configuration debug -Xswiftc -swift-version -Xswiftc ${{ matrix.swift-compat-ver }}
+        if [ $? != 0 ]; then
+          echo "Failed to build products with debug mode."
+          rm -rf $(cd .build/debug && pwd -P)
+        fi
+      continue-on-error: true
+    - name: Test with debug mode.
+      run: swift test --configuration debug -Xswiftc -swift-version -Xswiftc ${{ matrix.swift-compat-ver }}
+    - name: Try to build products with release mode.
+      run: |
+        swift build --configuration release -Xswiftc -enable-testing -Xswiftc -swift-version -Xswiftc ${{ matrix.swift-compat-ver }}
+        if [ $? != 0 ]; then
+          echo "Failed to build products with release mode."
+          rm -rf $(cd .build/release && pwd -P)
+        fi
+      continue-on-error: true
+    - name: Test with release mode.
+      run: swift test --configuration release -Xswiftc -enable-testing -Xswiftc -swift-version -Xswiftc ${{ matrix.swift-compat-ver }}
diff --git a/.gitignore b/.gitignore
index 5cd1097..e0e5082 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,6 @@
 .DS_Store
 
-.build/
+.build
 build/
 y-build/
 
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index c72197f..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,28 +0,0 @@
-branches:
-  except:
-    - /^\d+\.\d+\.\d+(-\S*)?$/
-
-os:
-  - linux
-  - osx
-language: generic
-sudo: required
-osx_image: xcode10.2
-dist: xenial
-env:
-  - SWIFT_BUILD_OPTION="-Xswiftc -swift-version -Xswiftc 4"
-  - SWIFT_BUILD_OPTION="-Xswiftc -swift-version -Xswiftc 4.2"
-  - SWIFT_BUILD_OPTION="-Xswiftc -swift-version -Xswiftc 5"
-before_install:
-  - |
-    if [ $(uname) = "Linux" ]; then
-      export SWIFT_ARCHIVE_URL="https://swift.org/builds/swift-5.0-release/ubuntu1604/swift-5.0-RELEASE/swift-5.0-RELEASE-ubuntu16.04.tar.gz"
-      curl ${SWIFT_ARCHIVE_URL} -o ../swift.tar.gz
-      mkdir ../swift
-      tar xzf ../swift.tar.gz -C ../swift --strip-components 2
-      export PATH="$(dirname $(pwd))/swift/bin:$PATH"
-    fi
-script:
-  - swift build ${SWIFT_BUILD_OPTION}
-  - swift build --configuration release ${SWIFT_BUILD_OPTION}
-  - swift test ${SWIFT_BUILD_OPTION}