head to head · open source
Tailcall vs optillm
Tailcall has 7,637 GitHub stars, 1,467 forks, 45 open issues and last shipped yesterday. optillm has 4,296 stars, 388 forks, 23 open issues and last shipped 3 days ago. Tailcall leads on adoption by 78% (7,637 vs 4,296 stars). Tailcall is written in Rust under Apache-2.0; optillm is written in Python under Apache-2.0. Tailcall has attracted 19% as many forks as stars, optillm 9%. Tailcall was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (llm), 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
| Tailcall | optillm | |
|---|---|---|
| GitHub stars | ★ 7.6K | ★ 4.3K |
| License | Apache-2.0 | Apache-2.0 |
| Written in | Rust | Python |
| Last push | 2026-09-19 | 2026-09-17 |
| Forks | ⑂ 1.5K | ⑂ 388 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Tailcall if
- You weight community size — 7.6K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches Rust
- You value the larger contributor base for long-term maintenance
pick optillm if
- You want the optillm 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 optillm fits your workflow better
About Tailcall
Tailcall is an Apache 2.0 licensed, Rust based developer tool listed in this registry whose repository (tailcallhq/forgecode) and README present it as Forge, an AI enhanced terminal development environment: a command line coding agent that works against Claude, GPT, O Series, Grok, Deepseek, Gemini and, per its own description, more than 300 other models.
read the full Tailcall overview →
About optillm
OptiLLM is a Python project that provides an optimizing inference proxy for large language models. It exposes an OpenAI API compatible endpoint and sits between an application and model providers, allowing callers to request reasoning oriented optimizations without changing model weights or adding training. The project lives in the developer tools and API development ecosystem, and its topics connect it to agents, agentic workflows, API gateways, chain of thought prompting, and generative AI inference.
read the full optillm overview →
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Frequently asked questions
Is Tailcall or optillm more popular?
Tailcall has 7,637 GitHub stars and optillm has 4,296. Tailcall has the larger community by that measure.
Are Tailcall and optillm free?
Both are open source. Tailcall is licensed under Apache-2.0 and optillm under Apache-2.0. Neither carries a licence fee.
What is the difference between Tailcall and optillm?
Tailcall is written in Rust and optillm 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, Tailcall or optillm?
Choose Tailcall if you want the larger community (7,637 stars) or its Apache-2.0 licence terms. Choose optillm if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.