head to head · open source
plannotator vs mantis
plannotator has 9,838 GitHub stars, 737 forks, 155 open issues and last shipped yesterday. mantis has 2,704 stars, 224 forks, 1 open issues and last shipped 2 days ago. plannotator leads on adoption by 264% (9,838 vs 2,704 stars). plannotator is written in TypeScript under Apache-2.0; mantis is written in Python under Apache-2.0. plannotator has attracted 7% as many forks as stars, mantis 8%. plannotator was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (code-review), so they are genuine substitutes rather than adjacent tools.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| plannotator | mantis | |
|---|---|---|
| GitHub stars | ★ 9.8K | ★ 2.7K |
| License | Apache-2.0 | Apache-2.0 |
| Written in | TypeScript | Python |
| Last push | 2026-11-04 | 2026-11-03 |
| Forks | ⑂ 737 | ⑂ 224 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick plannotator if
- You weight community size — 9.8K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches TypeScript
- You value the larger contributor base for long-term maintenance
pick mantis if
- You want the mantis feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Python
- You evaluated both and mantis fits your workflow better
About plannotator
Everything you need to annotate and stay in the loop with your agents Markdown Review • Code Review • HTML Artifacts Annotate plans, specs, markdown, and HTML before implementation. Review diffs and PRs. Send feedback to your agent. Watch the og demo · Installation guide · Official site · Visual HTML Skills · Herdr Annotate Plannotator Plannotator is a local, browser based review surface for AI coding agents: Claude Code, Codex, Copilot CLI, Gemini CLI, OpenCode, Kiro, Droid, Amp, and Pi. It plugs directly into your agent through its hooks and commands. When the agent proposes a plan, html, or finishes writing…
read the full plannotator overview →
About mantis
Mantis: Portable Toolkit for Building Secure Software [!CAUTION] USE AT YOUR OWN RISK. BE EXTREMELY CAREFUL. This suite is designed to generate and execute autonomously generated code that may be unstable or perform unexpected actions. USE THIS ONLY IN ISOLATED, RESTRICTED ENVIRONMENTS. Never run this suite on a machine with access to production systems, sensitive data, or internal networks. [!IMPORTANT] RESPONSIBLE USE AI models are non deterministic and can hallucinate findings or generate incorrect patches. All findings must be manually verified by a security expert before being reported. Do not mass file…
read the full mantis overview →
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Frequently asked questions
Is plannotator or mantis more popular?
plannotator has 9,838 GitHub stars and mantis has 2,704. plannotator has the larger community by that measure.
Are plannotator and mantis free?
Both are open source. plannotator is licensed under Apache-2.0 and mantis under Apache-2.0. Neither carries a licence fee.
What is the difference between plannotator and mantis?
plannotator is written in TypeScript and mantis in Python. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, plannotator or mantis?
Choose plannotator if you want the larger community (9,838 stars) or its Apache-2.0 licence terms. Choose mantis if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.