head to head · open source
ponytail vs Letta
ponytail has 182,779 GitHub stars, 10,094 forks, 270 open issues and last shipped 5 days ago. Letta has 3,764 stars, 465 forks, 347 open issues and last shipped yesterday. ponytail leads on adoption by 4,756% (182,779 vs 3,764 stars). ponytail is written in JavaScript under MIT; Letta is written in TypeScript under Apache-2.0. ponytail has attracted 6% as many forks as stars, Letta 12%. Letta was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (claude), 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.
← all 20902 open source comparisons
Side by side
| ponytail | Letta | |
|---|---|---|
| GitHub stars | ★ 183K | ★ 3.8K |
| License | MIT | Apache-2.0 |
| Written in | JavaScript | TypeScript |
| Last push | 2026-10-29 | 2026-11-02 |
| Forks | ⑂ 10K | ⑂ 465 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick ponytail if
- You weight community size — 183K stars and counting
- You want the MIT license terms
- Your stack matches JavaScript
- You value the larger contributor base for long-term maintenance
pick Letta if
- You want the Letta feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches TypeScript
- You evaluated both and Letta fits your workflow better
About ponytail
Ponytail He says nothing. He writes one line. It works. 54% less code (up to 94%) · 20% cheaper · 27% faster · 100% safe Measured on real Claude Code sessions editing a real open source repo (FastAPI + React), against the same agent with no skill. 54% is the mean across 12 feature tasks (Haiku 4.5, n=4); it reaches 94% where an agent over builds (a date picker) and is near zero where the code is already minimal. ponytail keeps every safety guard while a bare "write one liners" prompt drops one. (The earlier single shot benchmark reported 80 94% as a flat figure; against a fair agentic…
read the full ponytail overview →
About Letta
Letta Code Letta Code is a stateful agent harness for creating agents that are more like people than tools. Letta Code agents have memory, identity, and a sense of experience over time. They learn and evolve over long horizons through rewriting their own memory, skills, prompts, and even the harness itself (through mods). Letta Code can be used interactively, or to power always on agents that work proactively. Interact with agents through: A local CLI The desktop app for macOS, Windows, and Linux Your browser, including mobile, at chat.letta.com Messaging integrations, including Telegram, Slack, Discord, and…
read the full Letta overview →
More in AI & Machine Learning
Related comparisons
More AI Development Platforms projects
Compare either of these against the rest of the AI Development Platforms field.
Frequently asked questions
Is ponytail or Letta more popular?
ponytail has 182,779 GitHub stars and Letta has 3,764. ponytail has the larger community by that measure.
Are ponytail and Letta free?
Both are open source. ponytail is licensed under MIT and Letta under Apache-2.0. Neither carries a licence fee.
What is the difference between ponytail and Letta?
ponytail is written in JavaScript and Letta in TypeScript. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, ponytail or Letta?
Choose ponytail if you want the larger community (182,779 stars) or its MIT licence terms. Choose Letta if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.