head to head · open source
headroom vs CL4R1T4S
headroom has 73,130 GitHub stars, 5,624 forks, 643 open issues and last shipped yesterday. CL4R1T4S has 50,059 stars, 10,280 forks, 127 open issues and last shipped 10 days ago. headroom leads on adoption by 46% (73,130 vs 50,059 stars). headroom is written in Python under Apache-2.0; CL4R1T4S is written in various languages under AGPL-3.0. headroom has attracted 8% as many forks as stars, CL4R1T4S 21%. headroom was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (ai), 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
| headroom | CL4R1T4S | |
|---|---|---|
| GitHub stars | ★ 73K | ★ 50K |
| License | Apache-2.0 | AGPL-3.0 |
| Written in | Python | — |
| Last push | 2026-09-19 | 2026-09-10 |
| Forks | ⑂ 5.6K | ⑂ 10K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick headroom if
- You weight community size — 73K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches Python
- You value the larger contributor base for long-term maintenance
pick CL4R1T4S if
- You want the CL4R1T4S feature set and don't need the biggest community
- You prefer the AGPL-3.0 license terms
- You evaluated both and CL4R1T4S fits your workflow better
About headroom
Headroom is an Apache 2.0 Python library, local proxy, agent wrapper and MCP server that compresses tool outputs, logs, files, RAG chunks and conversation history before they reach an LLM, and it is built for developers running AI coding agents or LLM applications who want to cut token usage without changing the answers they get.
read the full headroom overview →
About CL4R1T4S
CL4R1T4S is an AGPL 3.0 repository of full extracted system prompts, guidelines and tools from the major AI models and agents — ChatGPT, Claude, Gemini, Grok, Perplexity, Cursor, Lovable, Replit and more — for anyone who wants to know what instructions sit behind the AI systems they use.
read the full CL4R1T4S overview →
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Frequently asked questions
Is headroom or CL4R1T4S more popular?
headroom has 73,130 GitHub stars and CL4R1T4S has 50,059. headroom has the larger community by that measure.
Are headroom and CL4R1T4S free?
Both are open source. headroom is licensed under Apache-2.0 and CL4R1T4S under AGPL-3.0. Neither carries a licence fee.
What is the difference between headroom and CL4R1T4S?
headroom is written in Python and CL4R1T4S in various languages. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, headroom or CL4R1T4S?
Choose headroom if you want the larger community (73,130 stars) or its Apache-2.0 licence terms. Choose CL4R1T4S if its feature set, stack or AGPL-3.0 licence fits better. Both are self-hostable.