head to head · open source
ECC vs msw
ECC has 261,896 GitHub stars, 39,186 forks, 228 open issues and last shipped 2 days ago. msw has 18,210 stars, 626 forks, 37 open issues and last shipped yesterday. ECC leads on adoption by 1,338% (261,896 vs 18,210 stars). ECC is written in JavaScript under MIT; msw is written in TypeScript under MIT. ECC has attracted 15% as many forks as stars, msw 3%. msw was the more recently maintained of the two, and both are self-hostable with no licence fee.
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
| ECC | msw | |
|---|---|---|
| GitHub stars | ★ 262K | ★ 18K |
| License | MIT | MIT |
| Written in | JavaScript | TypeScript |
| Last push | 2026-09-17 | 2026-09-18 |
| Forks | ⑂ 39K | ⑂ 626 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick ECC if
- You weight community size — 262K stars and counting
- You want the MIT license terms
- Your stack matches JavaScript
- You value the larger contributor base for long-term maintenance
pick msw if
- You want the msw feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches TypeScript
- You evaluated both and msw fits your workflow better
About ECC
ECC is an MIT licensed open source agent harness performance optimization system that gives AI coding agents a coordinated engineering workflow — plan, test, implement, review, verify, remember, improve — for developers working in Claude Code, Codex, OpenCode, Cursor, and other harnesses.
About msw
Mock Service Worker (MSW) is an MIT licensed TypeScript library that intercepts network requests at the Service Worker level so JavaScript applications and tests can run against mocked APIs without any change to application code, and it is built for front end and full stack JavaScript developers who need consistent API mocking in the browser, in tests, and during local development.
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Frequently asked questions
Is ECC or msw more popular?
ECC has 261,896 GitHub stars and msw has 18,210. ECC has the larger community by that measure.
Are ECC and msw free?
Both are open source. ECC is licensed under MIT and msw under MIT. Neither carries a licence fee.
What is the difference between ECC and msw?
ECC is written in JavaScript and msw 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, ECC or msw?
Choose ECC if you want the larger community (261,896 stars) or its MIT licence terms. Choose msw if its feature set, stack or MIT licence fits better. Both are self-hostable.