JSON to io-ts Codecs
Generate io-ts runtime codecs and types from JSON.
Use JSON to io-ts Codecs to skip the boilerplate of hand-writing data models. It's the go-to free choice when you're consuming a JSON API and need matching io-ts Codecs fast — paste, copy, done. No sign-up, no install, and your payload never leaves the browser.
About JSON to io-ts Codecs
Building a typed app and tired of hand-writing models? JSON to io-ts Codecs turns a real JSON payload into io-ts Codecs in a single paste — it generate io-ts runtime codecs and types from JSON. Drop in an API response, copy the generated code, and keep your types in lockstep with the data. Like every ToolJolt utility it runs 100% in your browser — no sign-up, no upload, and nothing ever sent to a server, so it's safe for proprietary code and confidential data.
How to use JSON to io-ts Codecs
- 1Paste a representative JSON payload (an API response works great).
- 2The tool infers the field types and nested structures instantly.
- 3Review the generated code, then copy or download it straight into your project.
- 4Tweak the JSON and re-run any time — it's free and unlimited.
Why use JSON to io-ts Codecs?
- ✓Infers types automatically from a real JSON sample
- ✓Handles nested objects and arrays of objects
- ✓Copy or download the generated types in one click
- ✓Saves the tedious, error-prone work of writing models by hand
Frequently asked questions
How does JSON to io-ts Codecs infer types?+
It walks your JSON sample and maps each value to the closest static type — numbers, strings, booleans, arrays and nested objects each become the idiomatic type for the target language. Provide a complete example for the most accurate result.
Will the generated code compile as-is?+
It's designed to drop straight in, but you should review naming and nullability. JSON can't express every nuance (e.g. unions or optionals), so treat the output as a strong first draft you can refine.
Is JSON to io-ts Codecs free?+
Yes. JSON to io-ts Codecs is completely free with no sign-up, no account, no usage limits and no watermarks. Use it as often as you like.
Does JSON to io-ts Codecs send my data to a server?+
No. JSON to io-ts Codecs runs entirely in your browser with JavaScript — your input never leaves your device, which makes it safe for private API payloads, schemas and source code.
Embed JSON to io-ts Codecs on your website
Want JSON to io-ts Codecson your own site? Paste this snippet into any HTML page — it's free, with no API key or sign-up. The tool loads in an iframe and keeps working exactly as it does here.
<iframe src="https://tooljolt.com/tools/json-to-io-ts" width="100%" height="640" style="border:1px solid #e5e7eb;border-radius:12px;max-width:680px" title="JSON to io-ts Codecs — ToolJolt" loading="lazy"></iframe>Related Data tools
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