OpenTailcat

Android client for Tailcat. Paste a tc… token and connect to your gateway — no control plane in the middle.

Independent community project. Not affiliated with Tailscale Inc.

Screenshots

 

What’s new in 1.5.1

• Fail-closed lifecycle fixes: the new routed interface can no longer be cleared by a recycled file descriptor, and vpnWanted is stored synchronously so a kill cannot resurrect an unwanted VPN.
• Agreement fixes: stored profile MTUs are clamped to 1280–1500, token IPv4 literals reject leading zeroes like Go and the DNS validator, and network-state update failures are logged instead of swallowed.
• Native engine: a panicking TCP dial can no longer pin a connection slot forever, and Stop clears the staged MTU as well as the staged DNS.

Full notes: docs/releases/1.5.1.md. Older releases: docs/releases/.

Install

1. Grab the latest release.
2. APKs:
   • Phone: OpenTailcat-1.5.1-arm64-v8a.apk
   • Emulator (x86_64): OpenTailcat-1.5.1-x86_64.apk
3. Install it (allow installs from your browser/file manager if asked).
4. Optional: enable Always-on VPN and Block connections without VPN for OpenTailcat — better if the tunnel drops. Connect still works without them.
5. Paste your tc… token and tap Connect.

Checksums are in OpenTailcat-1.5.1-SHA256SUMS.txt.

How it works

You run a Tailcat-compatible exit gateway. It gives you a short token. OpenTailcat uses that token to tunnel to your gateway.

Notes

• Builds are development-signed unless you set OPENTAILCAT_RELEASE_*. Uninstall an older development install if Android blocks the upgrade.
• More detail: docs/releases/, AGENTS.md, handoff.md.

License

Apache License 2.0 — LICENSE, PRIVACY_POLICY.md.