diff --git a/.github/workflows/license-headers.yml b/.github/workflows/license-headers.yml
new file mode 100644
index 0000000..2a78455
--- /dev/null
+++ b/.github/workflows/license-headers.yml
@@ -0,0 +1,19 @@
+on:
+  push:
+    branches:
+      - "main"
+      - "release-branch/*"
+  pull_request:
+    # all PRs on all branches
+  merge_group:
+    branches:
+      - "main"
+
+jobs:
+  license_headers:
+    runs-on: ubuntu-latest
+    steps:
+      - name: checkout
+        uses: actions/checkout@v4
+      - name: check license headers
+        run: ./scripts/check_license_headers.sh .
diff --git a/android/src/main/java/com/tailscale/ipn/App.java b/android/src/main/java/com/tailscale/ipn/App.java
index d44efaf..cae86c9 100644
--- a/android/src/main/java/com/tailscale/ipn/App.java
+++ b/android/src/main/java/com/tailscale/ipn/App.java
@@ -1,6 +1,5 @@
-// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn;
 
diff --git a/android/src/main/java/com/tailscale/ipn/DnsConfig.java b/android/src/main/java/com/tailscale/ipn/DnsConfig.java
index dfe6e8c..19209de 100644
--- a/android/src/main/java/com/tailscale/ipn/DnsConfig.java
+++ b/android/src/main/java/com/tailscale/ipn/DnsConfig.java
@@ -1,6 +1,5 @@
-// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn;
 
diff --git a/android/src/main/java/com/tailscale/ipn/IPNActivity.java b/android/src/main/java/com/tailscale/ipn/IPNActivity.java
index 340697d..4501d43 100644
--- a/android/src/main/java/com/tailscale/ipn/IPNActivity.java
+++ b/android/src/main/java/com/tailscale/ipn/IPNActivity.java
@@ -1,6 +1,5 @@
-// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn;
 
diff --git a/android/src/main/java/com/tailscale/ipn/IPNReceiver.java b/android/src/main/java/com/tailscale/ipn/IPNReceiver.java
index ea6cb75..a299500 100644
--- a/android/src/main/java/com/tailscale/ipn/IPNReceiver.java
+++ b/android/src/main/java/com/tailscale/ipn/IPNReceiver.java
@@ -1,6 +1,5 @@
-// Copyright (c) 2023 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn;
 
diff --git a/android/src/main/java/com/tailscale/ipn/IPNService.java b/android/src/main/java/com/tailscale/ipn/IPNService.java
index fee5b9e..9c4dbb1 100644
--- a/android/src/main/java/com/tailscale/ipn/IPNService.java
+++ b/android/src/main/java/com/tailscale/ipn/IPNService.java
@@ -1,6 +1,5 @@
-// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn;
 
diff --git a/android/src/main/java/com/tailscale/ipn/Peer.java b/android/src/main/java/com/tailscale/ipn/Peer.java
index 22cf9c9..a5c49e7 100644
--- a/android/src/main/java/com/tailscale/ipn/Peer.java
+++ b/android/src/main/java/com/tailscale/ipn/Peer.java
@@ -1,6 +1,5 @@
-// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn;
 
diff --git a/android/src/main/java/com/tailscale/ipn/QuickToggleService.java b/android/src/main/java/com/tailscale/ipn/QuickToggleService.java
index ec341be..f77a30c 100644
--- a/android/src/main/java/com/tailscale/ipn/QuickToggleService.java
+++ b/android/src/main/java/com/tailscale/ipn/QuickToggleService.java
@@ -1,6 +1,5 @@
-// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn;
 
diff --git a/android/src/main/java/com/tailscale/ipn/StartVPNWorker.java b/android/src/main/java/com/tailscale/ipn/StartVPNWorker.java
index e4a0b4d..5defe23 100644
--- a/android/src/main/java/com/tailscale/ipn/StartVPNWorker.java
+++ b/android/src/main/java/com/tailscale/ipn/StartVPNWorker.java
@@ -1,6 +1,5 @@
-// Copyright (c) 2023 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn;
 
diff --git a/android/src/main/java/com/tailscale/ipn/StopVPNWorker.java b/android/src/main/java/com/tailscale/ipn/StopVPNWorker.java
index 296ce28..2d2a378 100644
--- a/android/src/main/java/com/tailscale/ipn/StopVPNWorker.java
+++ b/android/src/main/java/com/tailscale/ipn/StopVPNWorker.java
@@ -1,6 +1,5 @@
-// Copyright (c) 2023 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn;
 
diff --git a/android/src/main/java/com/tailscale/ipn/ui/localapi/LocalAPIClient.kt b/android/src/main/java/com/tailscale/ipn/ui/localapi/LocalAPIClient.kt
index 3f1ab79..d9421b3 100644
--- a/android/src/main/java/com/tailscale/ipn/ui/localapi/LocalAPIClient.kt
+++ b/android/src/main/java/com/tailscale/ipn/ui/localapi/LocalAPIClient.kt
@@ -1,6 +1,5 @@
-// Copyright (c) 2024 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn.ui.localapi
 
diff --git a/android/src/main/java/com/tailscale/ipn/ui/localapi/LocalAPIRequest.kt b/android/src/main/java/com/tailscale/ipn/ui/localapi/LocalAPIRequest.kt
index 836f63e..4829bbb 100644
--- a/android/src/main/java/com/tailscale/ipn/ui/localapi/LocalAPIRequest.kt
+++ b/android/src/main/java/com/tailscale/ipn/ui/localapi/LocalAPIRequest.kt
@@ -1,6 +1,5 @@
-// Copyright (c) 2024 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn.ui.localapi
 
diff --git a/android/src/main/java/com/tailscale/ipn/ui/localapi/Result.kt b/android/src/main/java/com/tailscale/ipn/ui/localapi/Result.kt
index a80f925..5965089 100644
--- a/android/src/main/java/com/tailscale/ipn/ui/localapi/Result.kt
+++ b/android/src/main/java/com/tailscale/ipn/ui/localapi/Result.kt
@@ -1,6 +1,5 @@
-// Copyright (c) 2024 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn.ui.localapi
 
diff --git a/android/src/main/java/com/tailscale/ipn/ui/model/Dns.kt b/android/src/main/java/com/tailscale/ipn/ui/model/Dns.kt
index c1f97fe..cf047a0 100644
--- a/android/src/main/java/com/tailscale/ipn/ui/model/Dns.kt
+++ b/android/src/main/java/com/tailscale/ipn/ui/model/Dns.kt
@@ -1,6 +1,5 @@
-// Copyright (c) 2024 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn.ui.model
 
diff --git a/android/src/main/java/com/tailscale/ipn/ui/model/Ipn.kt b/android/src/main/java/com/tailscale/ipn/ui/model/Ipn.kt
index 6b1c007..32d76ac 100644
--- a/android/src/main/java/com/tailscale/ipn/ui/model/Ipn.kt
+++ b/android/src/main/java/com/tailscale/ipn/ui/model/Ipn.kt
@@ -1,6 +1,5 @@
-// Copyright (c) 2024 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn.ui.model
 
diff --git a/android/src/main/java/com/tailscale/ipn/ui/model/IpnState.kt b/android/src/main/java/com/tailscale/ipn/ui/model/IpnState.kt
index f187e5c..826ca42 100644
--- a/android/src/main/java/com/tailscale/ipn/ui/model/IpnState.kt
+++ b/android/src/main/java/com/tailscale/ipn/ui/model/IpnState.kt
@@ -1,6 +1,5 @@
-// Copyright (c) 2024 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn.ui.model
 
diff --git a/android/src/main/java/com/tailscale/ipn/ui/model/NetMap.kt b/android/src/main/java/com/tailscale/ipn/ui/model/NetMap.kt
index 623b104..57ce19d 100644
--- a/android/src/main/java/com/tailscale/ipn/ui/model/NetMap.kt
+++ b/android/src/main/java/com/tailscale/ipn/ui/model/NetMap.kt
@@ -1,6 +1,5 @@
-// Copyright (c) 2024 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn.ui.model
 
diff --git a/android/src/main/java/com/tailscale/ipn/ui/model/TailCfg.kt b/android/src/main/java/com/tailscale/ipn/ui/model/TailCfg.kt
index 4e94f8e..5669300 100644
--- a/android/src/main/java/com/tailscale/ipn/ui/model/TailCfg.kt
+++ b/android/src/main/java/com/tailscale/ipn/ui/model/TailCfg.kt
@@ -1,6 +1,5 @@
-// Copyright (c) 2024 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn.ui.model
 
diff --git a/android/src/main/java/com/tailscale/ipn/ui/model/Types.kt b/android/src/main/java/com/tailscale/ipn/ui/model/Types.kt
index ff70f75..e0158c1 100644
--- a/android/src/main/java/com/tailscale/ipn/ui/model/Types.kt
+++ b/android/src/main/java/com/tailscale/ipn/ui/model/Types.kt
@@ -1,6 +1,5 @@
-// Copyright (c) 2024 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn.ui.model
 
diff --git a/android/src/main/java/com/tailscale/ipn/ui/notifier/Notifier.kt b/android/src/main/java/com/tailscale/ipn/ui/notifier/Notifier.kt
index 2936ca3..df2acb4 100644
--- a/android/src/main/java/com/tailscale/ipn/ui/notifier/Notifier.kt
+++ b/android/src/main/java/com/tailscale/ipn/ui/notifier/Notifier.kt
@@ -1,6 +1,5 @@
-// Copyright (c) 2024 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn.ui.notifier
 
diff --git a/android/src/main/java/com/tailscale/ipn/ui/service/IpnManager.kt b/android/src/main/java/com/tailscale/ipn/ui/service/IpnManager.kt
index 23cc17e..e4b8d36 100644
--- a/android/src/main/java/com/tailscale/ipn/ui/service/IpnManager.kt
+++ b/android/src/main/java/com/tailscale/ipn/ui/service/IpnManager.kt
@@ -1,6 +1,5 @@
-// Copyright (c) 2024 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn.ui.service
 
diff --git a/android/src/main/java/com/tailscale/ipn/ui/service/IpnModel.kt b/android/src/main/java/com/tailscale/ipn/ui/service/IpnModel.kt
index 2ec3d79..2f0d5e3 100644
--- a/android/src/main/java/com/tailscale/ipn/ui/service/IpnModel.kt
+++ b/android/src/main/java/com/tailscale/ipn/ui/service/IpnModel.kt
@@ -1,6 +1,5 @@
-// Copyright (c) 2024 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn.ui.service
 
diff --git a/android/src/play/java/com/tailscale/ipn/Google.java b/android/src/play/java/com/tailscale/ipn/Google.java
index 44f8226..44a4787 100644
--- a/android/src/play/java/com/tailscale/ipn/Google.java
+++ b/android/src/play/java/com/tailscale/ipn/Google.java
@@ -1,6 +1,5 @@
-// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn;
 
diff --git a/android_legacy/src/main/java/com/tailscale/ipn/App.java b/android_legacy/src/main/java/com/tailscale/ipn/App.java
index d44efaf..cae86c9 100644
--- a/android_legacy/src/main/java/com/tailscale/ipn/App.java
+++ b/android_legacy/src/main/java/com/tailscale/ipn/App.java
@@ -1,6 +1,5 @@
-// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn;
 
diff --git a/android_legacy/src/main/java/com/tailscale/ipn/DnsConfig.java b/android_legacy/src/main/java/com/tailscale/ipn/DnsConfig.java
index dfe6e8c..19209de 100644
--- a/android_legacy/src/main/java/com/tailscale/ipn/DnsConfig.java
+++ b/android_legacy/src/main/java/com/tailscale/ipn/DnsConfig.java
@@ -1,6 +1,5 @@
-// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn;
 
diff --git a/android_legacy/src/main/java/com/tailscale/ipn/IPNActivity.java b/android_legacy/src/main/java/com/tailscale/ipn/IPNActivity.java
index 340697d..4501d43 100644
--- a/android_legacy/src/main/java/com/tailscale/ipn/IPNActivity.java
+++ b/android_legacy/src/main/java/com/tailscale/ipn/IPNActivity.java
@@ -1,6 +1,5 @@
-// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn;
 
diff --git a/android_legacy/src/main/java/com/tailscale/ipn/IPNReceiver.java b/android_legacy/src/main/java/com/tailscale/ipn/IPNReceiver.java
index ea6cb75..a299500 100644
--- a/android_legacy/src/main/java/com/tailscale/ipn/IPNReceiver.java
+++ b/android_legacy/src/main/java/com/tailscale/ipn/IPNReceiver.java
@@ -1,6 +1,5 @@
-// Copyright (c) 2023 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn;
 
diff --git a/android_legacy/src/main/java/com/tailscale/ipn/IPNService.java b/android_legacy/src/main/java/com/tailscale/ipn/IPNService.java
index fee5b9e..9c4dbb1 100644
--- a/android_legacy/src/main/java/com/tailscale/ipn/IPNService.java
+++ b/android_legacy/src/main/java/com/tailscale/ipn/IPNService.java
@@ -1,6 +1,5 @@
-// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn;
 
diff --git a/android_legacy/src/main/java/com/tailscale/ipn/Peer.java b/android_legacy/src/main/java/com/tailscale/ipn/Peer.java
index 22cf9c9..a5c49e7 100644
--- a/android_legacy/src/main/java/com/tailscale/ipn/Peer.java
+++ b/android_legacy/src/main/java/com/tailscale/ipn/Peer.java
@@ -1,6 +1,5 @@
-// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn;
 
diff --git a/android_legacy/src/main/java/com/tailscale/ipn/QuickToggleService.java b/android_legacy/src/main/java/com/tailscale/ipn/QuickToggleService.java
index ec341be..f77a30c 100644
--- a/android_legacy/src/main/java/com/tailscale/ipn/QuickToggleService.java
+++ b/android_legacy/src/main/java/com/tailscale/ipn/QuickToggleService.java
@@ -1,6 +1,5 @@
-// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn;
 
diff --git a/android_legacy/src/main/java/com/tailscale/ipn/StartVPNWorker.java b/android_legacy/src/main/java/com/tailscale/ipn/StartVPNWorker.java
index e4a0b4d..5defe23 100644
--- a/android_legacy/src/main/java/com/tailscale/ipn/StartVPNWorker.java
+++ b/android_legacy/src/main/java/com/tailscale/ipn/StartVPNWorker.java
@@ -1,6 +1,5 @@
-// Copyright (c) 2023 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn;
 
diff --git a/android_legacy/src/main/java/com/tailscale/ipn/StopVPNWorker.java b/android_legacy/src/main/java/com/tailscale/ipn/StopVPNWorker.java
index 296ce28..2d2a378 100644
--- a/android_legacy/src/main/java/com/tailscale/ipn/StopVPNWorker.java
+++ b/android_legacy/src/main/java/com/tailscale/ipn/StopVPNWorker.java
@@ -1,6 +1,5 @@
-// Copyright (c) 2023 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn;
 
diff --git a/android_legacy/src/main/java/com/tailscale/ipn/ui/localapi/LocalAPIClient.kt b/android_legacy/src/main/java/com/tailscale/ipn/ui/localapi/LocalAPIClient.kt
index 9741679..e065098 100644
--- a/android_legacy/src/main/java/com/tailscale/ipn/ui/localapi/LocalAPIClient.kt
+++ b/android_legacy/src/main/java/com/tailscale/ipn/ui/localapi/LocalAPIClient.kt
@@ -1,6 +1,5 @@
-// Copyright (c) 2024 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn.ui.localapi
 
diff --git a/android_legacy/src/main/java/com/tailscale/ipn/ui/localapi/LocalAPIRequest.kt b/android_legacy/src/main/java/com/tailscale/ipn/ui/localapi/LocalAPIRequest.kt
index c9380d2..83f5705 100644
--- a/android_legacy/src/main/java/com/tailscale/ipn/ui/localapi/LocalAPIRequest.kt
+++ b/android_legacy/src/main/java/com/tailscale/ipn/ui/localapi/LocalAPIRequest.kt
@@ -1,6 +1,5 @@
-// Copyright (c) 2024 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn.ui.localapi
 
diff --git a/android_legacy/src/main/java/com/tailscale/ipn/ui/localapi/Result.kt b/android_legacy/src/main/java/com/tailscale/ipn/ui/localapi/Result.kt
index 7d9ec5a..4180171 100644
--- a/android_legacy/src/main/java/com/tailscale/ipn/ui/localapi/Result.kt
+++ b/android_legacy/src/main/java/com/tailscale/ipn/ui/localapi/Result.kt
@@ -1,6 +1,5 @@
-// Copyright (c) 2024 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn.ui.localapi
 
diff --git a/android_legacy/src/play/java/com/tailscale/ipn/Google.java b/android_legacy/src/play/java/com/tailscale/ipn/Google.java
index 44f8226..44a4787 100644
--- a/android_legacy/src/play/java/com/tailscale/ipn/Google.java
+++ b/android_legacy/src/play/java/com/tailscale/ipn/Google.java
@@ -1,6 +1,5 @@
-// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package com.tailscale.ipn;
 
diff --git a/cmd/jni/jni.go b/cmd/jni/jni.go
index 24f8ed4..0cfcb49 100644
--- a/cmd/jni/jni.go
+++ b/cmd/jni/jni.go
@@ -1,6 +1,5 @@
-// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 // Package jni implements various helper functions for communicating with the Android JVM
 // though JNI.
diff --git a/cmd/localapiservice/localapi_test.go b/cmd/localapiservice/localapi_test.go
index 0aef288..97f0d06 100644
--- a/cmd/localapiservice/localapi_test.go
+++ b/cmd/localapiservice/localapi_test.go
@@ -1,3 +1,6 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
 package localapiservice
 
 import (
diff --git a/cmd/localapiservice/localapiservice.go b/cmd/localapiservice/localapiservice.go
index ad925d4..6fa88f5 100644
--- a/cmd/localapiservice/localapiservice.go
+++ b/cmd/localapiservice/localapiservice.go
@@ -1,3 +1,6 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
 package localapiservice
 
 import (
diff --git a/cmd/localapiservice/localapishim.go b/cmd/localapiservice/localapishim.go
index ebb121e..d17c6db 100644
--- a/cmd/localapiservice/localapishim.go
+++ b/cmd/localapiservice/localapishim.go
@@ -1,6 +1,5 @@
-// Copyright (c) 2024 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package localapiservice
 
diff --git a/cmd/localapiservice/response.go b/cmd/localapiservice/response.go
index 477da84..9e30ebc 100644
--- a/cmd/localapiservice/response.go
+++ b/cmd/localapiservice/response.go
@@ -1,3 +1,6 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
 package localapiservice
 
 import (
diff --git a/cmd/tailscale/backend.go b/cmd/tailscale/backend.go
index 90b8abd..b8f75c6 100644
--- a/cmd/tailscale/backend.go
+++ b/cmd/tailscale/backend.go
@@ -1,6 +1,5 @@
-// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package main
 
@@ -15,8 +14,8 @@ import (
 	"strings"
 	"time"
 
-	"github.com/tailscale/wireguard-go/tun"
 	"github.com/tailscale/tailscale-android/cmd/jni"
+	"github.com/tailscale/wireguard-go/tun"
 
 	"golang.org/x/sys/unix"
 	"tailscale.com/ipn"
diff --git a/cmd/tailscale/callbacks.go b/cmd/tailscale/callbacks.go
index be3c793..6f5d1d5 100644
--- a/cmd/tailscale/callbacks.go
+++ b/cmd/tailscale/callbacks.go
@@ -1,6 +1,5 @@
-// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package main
 
diff --git a/cmd/tailscale/main.go b/cmd/tailscale/main.go
index f477190..e98718f 100644
--- a/cmd/tailscale/main.go
+++ b/cmd/tailscale/main.go
@@ -1,6 +1,5 @@
-// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package main
 
diff --git a/cmd/tailscale/multitun.go b/cmd/tailscale/multitun.go
index 8f2d016..4531f88 100644
--- a/cmd/tailscale/multitun.go
+++ b/cmd/tailscale/multitun.go
@@ -1,6 +1,5 @@
-// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package main
 
diff --git a/cmd/tailscale/pprof.go b/cmd/tailscale/pprof.go
index 9b81a47..e221874 100644
--- a/cmd/tailscale/pprof.go
+++ b/cmd/tailscale/pprof.go
@@ -1,6 +1,5 @@
-// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 //go:build pprof
 // +build pprof
diff --git a/cmd/tailscale/store.go b/cmd/tailscale/store.go
index 0da0c5c..e3f62d4 100644
--- a/cmd/tailscale/store.go
+++ b/cmd/tailscale/store.go
@@ -1,6 +1,5 @@
-// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package main
 
diff --git a/cmd/tailscale/tools.go b/cmd/tailscale/tools.go
index df1b621..6267d59 100644
--- a/cmd/tailscale/tools.go
+++ b/cmd/tailscale/tools.go
@@ -1,6 +1,5 @@
-// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 //go:build tools
 // +build tools
diff --git a/cmd/tailscale/ui.go b/cmd/tailscale/ui.go
index 0e28a17..1040039 100644
--- a/cmd/tailscale/ui.go
+++ b/cmd/tailscale/ui.go
@@ -1,6 +1,5 @@
-// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
 
 package main
 
diff --git a/scripts/check_license_headers.sh b/scripts/check_license_headers.sh
new file mode 100755
index 0000000..aaa9d13
--- /dev/null
+++ b/scripts/check_license_headers.sh
@@ -0,0 +1,47 @@
+#!/bin/sh
+#
+# Copyright (c) Tailscale Inc & AUTHORS
+# SPDX-License-Identifier: BSD-3-Clause
+#
+# check_license_headers.sh checks that source files in the given
+# directory tree have a correct-looking Tailscale license header.
+
+check_file() {
+	got=$1
+
+	want=$(
+		cat <<EOF
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+EOF
+	)
+	if [ "$got" = "$want" ]; then
+		return 0
+	fi
+	return 1
+}
+
+if [ $# != 1 ]; then
+	echo "Usage: $0 rootdir" >&2
+	exit 1
+fi
+
+fail=0
+for file in $(find $1 \( -name '*.go' -or -name '*.tsx' -or -name '*.ts' -or -name '*.kt' -or -name '*.java' -not -name '*.config.ts' \) -not -path '*/.git/*' -not -path '*/node_modules/*'); do
+	case $file in
+	*)
+		header="$(head -2 $file)"
+		;;
+	esac
+	if [ ! -z "$header" ]; then
+		if ! check_file "$header"; then
+			fail=1
+			echo "${file#$1/} doesn't have the right copyright header:"
+			echo "$header" | sed -e 's/^/    /g'
+		fi
+	fi
+done
+
+if [ $fail -ne 0 ]; then
+	exit 1
+fi