head to head · open source
Insomnia vs zato
Insomnia has 40,111 GitHub stars, 2,388 forks, 874 open issues and last shipped yesterday. zato has 1,017 stars, 250 forks, 0 open issues and last shipped yesterday. Insomnia leads on adoption by 3,844% (40,111 vs 1,017 stars). Insomnia is written in TypeScript under Apache-2.0; zato is written in Python under AGPL-3.0. Insomnia has attracted 6% as many forks as stars, zato 25%. zato was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (api), 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
| Insomnia | zato | |
|---|---|---|
| GitHub stars | ★ 40K | ★ 1.0K |
| License | Apache-2.0 | AGPL-3.0 |
| Written in | TypeScript | Python |
| Last push | 2026-11-02 | 2026-11-02 |
| Forks | ⑂ 2.4K | ⑂ 250 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Insomnia if
- You weight community size — 40K 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 zato if
- You want the zato feature set and don't need the biggest community
- You prefer the AGPL-3.0 license terms
- Your stack matches Python
- You evaluated both and zato fits your workflow better
About Insomnia
Insomnia API Client Insomnia is an open source, cross platform API client for GraphQL, REST, WebSockets, Server Sent Events (SSE), gRPC and any other HTTP compatible protocol. With Insomnia you can: Debug APIs using the most popular protocols and formats. Design APIs using the native OpenAPI editor and visual preview. Test APIs using native test suites and collection runner. Mock APIs using a cloud or self hosted mocking server. Build CI/CD pipelines using the native Insomnia CLI for linting and testing. Collaborate with others using the many collaboration features. And more including the ability to use 3rd…
read the full Insomnia overview →
About zato
Zato /zɑːtəʊ/ ESB, SOA, API and Cloud Integrations in Python. Zato is a Python based, open source platform that lets you automate, integrate and orchestrate business systems, APIs, workflows as well as hardware assets in industries such as airports, defense, health care, telecommunications, financial services, government and more. What does it look like in practice? Learn more Visit for the details, including: Downloads Screenshots Programming examples
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Frequently asked questions
Is Insomnia or zato more popular?
Insomnia has 40,111 GitHub stars and zato has 1,017. Insomnia has the larger community by that measure.
Are Insomnia and zato free?
Both are open source. Insomnia is licensed under Apache-2.0 and zato under AGPL-3.0. Neither carries a licence fee.
What is the difference between Insomnia and zato?
Insomnia is written in TypeScript and zato 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, Insomnia or zato?
Choose Insomnia if you want the larger community (40,111 stars) or its Apache-2.0 licence terms. Choose zato if its feature set, stack or AGPL-3.0 licence fits better. Both are self-hostable.