diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 0a3b49f..446d742 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -11,6 +11,13 @@ on:
 jobs:
   validate:
     runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        target:
+          - lint
+          - vendor-validate
+          - license-validate
     steps:
       -
         name: Checkout
@@ -19,7 +26,7 @@ jobs:
         name: Validate
         uses: docker/bake-action@v2
         with:
-          targets: validate
+          targets: ${{ matrix.target }}
 
   test:
     runs-on: ubuntu-latest
diff --git a/__mocks__/@actions/github.ts b/__mocks__/@actions/github.ts
index 578a3de..8a0e946 100644
--- a/__mocks__/@actions/github.ts
+++ b/__mocks__/@actions/github.ts
@@ -1,3 +1,19 @@
+/**
+ * Copyright 2023 actions-toolkit authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 import {jest} from '@jest/globals';
 
 export const context = {
diff --git a/__tests__/builder.test.ts b/__tests__/builder.test.ts
index 3d0ae28..4999243 100644
--- a/__tests__/builder.test.ts
+++ b/__tests__/builder.test.ts
@@ -1,3 +1,19 @@
+/**
+ * Copyright 2023 actions-toolkit authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 import {beforeEach, describe, expect, it, jest, test} from '@jest/globals';
 import * as fs from 'fs';
 import * as path from 'path';
diff --git a/__tests__/buildkit.test.ts b/__tests__/buildkit.test.ts
index c0f69a9..7266693 100644
--- a/__tests__/buildkit.test.ts
+++ b/__tests__/buildkit.test.ts
@@ -1,3 +1,19 @@
+/**
+ * Copyright 2023 actions-toolkit authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 import {describe, expect, it, jest, test, beforeEach, afterEach} from '@jest/globals';
 import * as fs from 'fs';
 import * as path from 'path';
diff --git a/__tests__/buildx.test.ts b/__tests__/buildx.test.ts
index 78ea338..6e2243b 100644
--- a/__tests__/buildx.test.ts
+++ b/__tests__/buildx.test.ts
@@ -1,3 +1,19 @@
+/**
+ * Copyright 2023 actions-toolkit authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 import {describe, expect, it, jest, test, beforeEach, afterEach} from '@jest/globals';
 import * as fs from 'fs';
 import * as path from 'path';
diff --git a/__tests__/context.test.ts b/__tests__/context.test.ts
index 74d7c19..af4980c 100644
--- a/__tests__/context.test.ts
+++ b/__tests__/context.test.ts
@@ -1,3 +1,19 @@
+/**
+ * Copyright 2023 actions-toolkit authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 import fs from 'fs';
 import path from 'path';
 import rimraf from 'rimraf';
diff --git a/__tests__/docker.test.ts b/__tests__/docker.test.ts
index 427d369..1ee1dfd 100644
--- a/__tests__/docker.test.ts
+++ b/__tests__/docker.test.ts
@@ -1,3 +1,19 @@
+/**
+ * Copyright 2023 actions-toolkit authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 import {beforeEach, describe, expect, it, jest} from '@jest/globals';
 import * as exec from '@actions/exec';
 
diff --git a/__tests__/git.test.ts b/__tests__/git.test.ts
index a4de324..c3d8712 100644
--- a/__tests__/git.test.ts
+++ b/__tests__/git.test.ts
@@ -1,3 +1,19 @@
+/**
+ * Copyright 2023 actions-toolkit authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 import {beforeEach, describe, expect, it, jest} from '@jest/globals';
 
 import {Git} from '../src/git';
diff --git a/__tests__/github.test.ts b/__tests__/github.test.ts
index e24ad32..7754b5a 100644
--- a/__tests__/github.test.ts
+++ b/__tests__/github.test.ts
@@ -1,3 +1,19 @@
+/**
+ * Copyright 2023 actions-toolkit authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 import {describe, expect, jest, it, beforeEach, afterEach} from '@jest/globals';
 import * as fs from 'fs';
 import * as path from 'path';
diff --git a/__tests__/util.test.ts b/__tests__/util.test.ts
index 8d9079e..87adffd 100644
--- a/__tests__/util.test.ts
+++ b/__tests__/util.test.ts
@@ -1,3 +1,19 @@
+/**
+ * Copyright 2023 actions-toolkit authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 import {beforeEach, describe, expect, it, jest, test} from '@jest/globals';
 import * as fs from 'fs';
 import * as path from 'path';
diff --git a/dev.Dockerfile b/dev.Dockerfile
index 581bdf1..6231f4f 100644
--- a/dev.Dockerfile
+++ b/dev.Dockerfile
@@ -1,5 +1,19 @@
 # syntax=docker/dockerfile:1
 
+# Copyright 2023 actions-toolkit authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
 ARG NODE_VERSION=16
 ARG DOCKER_VERSION=20.10.22
 ARG BUILDX_VERSION=0.10.0
diff --git a/docker-bake.hcl b/docker-bake.hcl
index 265860f..bb4b1d0 100644
--- a/docker-bake.hcl
+++ b/docker-bake.hcl
@@ -1,3 +1,17 @@
+// Copyright 2023 actions-toolkit authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 group "default" {
   targets = ["build"]
 }
@@ -7,7 +21,7 @@ group "pre-checkin" {
 }
 
 group "validate" {
-  targets = ["lint", "vendor-validate"]
+  targets = ["lint", "vendor-validate", "license-validate"]
 }
 
 target "build" {
@@ -69,3 +83,15 @@ target "publish" {
   output = ["type=cacheonly"]
   secret = ["id=NODE_AUTH_TOKEN,env=NODE_AUTH_TOKEN"]
 }
+
+target "license-validate" {
+  dockerfile = "./hack/dockerfiles/license.Dockerfile"
+  target = "validate"
+  output = ["type=cacheonly"]
+}
+
+target "license-update" {
+  dockerfile = "./hack/dockerfiles/license.Dockerfile"
+  target = "update"
+  output = ["."]
+}
diff --git a/hack/dockerfiles/license.Dockerfile b/hack/dockerfiles/license.Dockerfile
new file mode 100644
index 0000000..9127510
--- /dev/null
+++ b/hack/dockerfiles/license.Dockerfile
@@ -0,0 +1,47 @@
+# syntax=docker/dockerfile:1
+
+# Copyright 2023 actions-toolkit authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+ARG LICENSE_HOLDER="actions-toolkit authors"
+ARG LICENSE_TYPE="apache"
+ARG LICENSE_FILES=".*\(Dockerfile\|Makefile\|\.js\|\.ts\|\.hcl\|\.sh\)"
+ARG ADDLICENSE_VERSION="v1.0.0"
+
+FROM ghcr.io/google/addlicense:${ADDLICENSE_VERSION} AS addlicense
+
+FROM alpine:3.17 AS base
+WORKDIR /src
+RUN apk add --no-cache cpio findutils git
+
+FROM base AS set
+ARG LICENSE_HOLDER
+ARG LICENSE_TYPE
+ARG LICENSE_FILES
+RUN --mount=type=bind,target=.,rw \
+    --mount=from=addlicense,source=/app/addlicense,target=/usr/bin/addlicense \
+    find . -regex "${LICENSE_FILES}" -not -path "./.yarn/*" -not -path "./node_modules/*" | xargs addlicense -c "$LICENSE_HOLDER" -l "$LICENSE_TYPE" && \
+    mkdir /out && \
+    find . -regex "${LICENSE_FILES}" -not -path "./.yarn/*" -not -path "./node_modules/*" | cpio -pdm /out
+
+FROM scratch AS update
+COPY --from=set /out /
+
+FROM base AS validate
+ARG LICENSE_HOLDER
+ARG LICENSE_TYPE
+ARG LICENSE_FILES
+RUN --mount=type=bind,target=. \
+    --mount=from=addlicense,source=/app/addlicense,target=/usr/bin/addlicense \
+    find . -regex "${LICENSE_FILES}" -not -path "./.yarn/*" -not -path "./node_modules/*" | xargs addlicense -check -c "$LICENSE_HOLDER" -l "$LICENSE_TYPE"
diff --git a/jest.config.ts b/jest.config.ts
index 36661f0..455328b 100644
--- a/jest.config.ts
+++ b/jest.config.ts
@@ -1,3 +1,19 @@
+/**
+ * Copyright 2023 actions-toolkit authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 process.env = Object.assign({}, process.env, {
   GITHUB_REPOSITORY: 'docker/actions-toolkit',
   RUNNER_TEMP: '/tmp/github_runner',
diff --git a/src/builder.ts b/src/builder.ts
index 634a6e6..6240345 100644
--- a/src/builder.ts
+++ b/src/builder.ts
@@ -1,3 +1,19 @@
+/**
+ * Copyright 2023 actions-toolkit authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 import * as exec from '@actions/exec';
 
 import {Buildx} from './buildx';
diff --git a/src/buildkit.ts b/src/buildkit.ts
index 8186727..66cb270 100644
--- a/src/buildkit.ts
+++ b/src/buildkit.ts
@@ -1,3 +1,19 @@
+/**
+ * Copyright 2023 actions-toolkit authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 import fs from 'fs';
 import * as core from '@actions/core';
 import * as exec from '@actions/exec';
diff --git a/src/buildx.ts b/src/buildx.ts
index 427d027..69d48c1 100644
--- a/src/buildx.ts
+++ b/src/buildx.ts
@@ -1,3 +1,19 @@
+/**
+ * Copyright 2023 actions-toolkit authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 import fs from 'fs';
 import path from 'path';
 import * as core from '@actions/core';
diff --git a/src/context.ts b/src/context.ts
index 8854ef1..9c624b0 100644
--- a/src/context.ts
+++ b/src/context.ts
@@ -1,3 +1,19 @@
+/**
+ * Copyright 2023 actions-toolkit authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 import fs from 'fs';
 import os from 'os';
 import path from 'path';
diff --git a/src/docker.ts b/src/docker.ts
index 6d77c8b..dca238d 100644
--- a/src/docker.ts
+++ b/src/docker.ts
@@ -1,3 +1,19 @@
+/**
+ * Copyright 2023 actions-toolkit authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 import * as exec from '@actions/exec';
 
 export class Docker {
diff --git a/src/git.ts b/src/git.ts
index 217b037..459eae0 100644
--- a/src/git.ts
+++ b/src/git.ts
@@ -1,3 +1,19 @@
+/**
+ * Copyright 2023 actions-toolkit authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 import * as exec from '@actions/exec';
 
 export class Git {
diff --git a/src/github.ts b/src/github.ts
index c84857b..9efc29f 100644
--- a/src/github.ts
+++ b/src/github.ts
@@ -1,3 +1,19 @@
+/**
+ * Copyright 2023 actions-toolkit authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 import {GitHub as Octokit} from '@actions/github/lib/utils';
 import * as github from '@actions/github';
 import {components as OctoOpenApiTypes} from '@octokit/openapi-types';
diff --git a/src/toolkit.ts b/src/toolkit.ts
index ef17a0a..168e7ae 100644
--- a/src/toolkit.ts
+++ b/src/toolkit.ts
@@ -1,3 +1,19 @@
+/**
+ * Copyright 2023 actions-toolkit authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 import {Context} from './context';
 import {Buildx} from './buildx';
 import {BuildKit} from './buildkit';
diff --git a/src/util.ts b/src/util.ts
index 4a2a496..09fa0c9 100644
--- a/src/util.ts
+++ b/src/util.ts
@@ -1,3 +1,19 @@
+/**
+ * Copyright 2023 actions-toolkit authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 import * as core from '@actions/core';
 import {parse} from 'csv-parse/sync';