JSON to TypeScript Converter – Paste JSON, Get Interfaces
I built a small tool to save time when working with APIs: JSON to TypeScript Converter.
You paste JSON, and it gives you clean TypeScript interfaces—nothing more, nothing less. It handles nested objects, arrays, optional fields (based on null values), and basic type inference (string, number, boolean, null, arrays, objects). You can tweak naming (PascalCase, camelCase), choose export types, and toggle whether to mark null fields as optional.
It’s just a parser with a minimal UI—no accounts, no tracking, no signup. The whole thing runs in the browser. Your data never hits a server.
There’s a free tier that works fine for one-off conversions. If you use it regularly, there’s a $9/month Pro option that adds:
- Multi-interface generation (one interface per root object)
- Nested interface extraction (instead of inline types)
- Optional property detection (fields with
nullbecome?:) - Better array handling (detects mixed types, empty arrays)
- Persistent settings (keeps your naming/export prefs)
No lock-in. You copy the output and move on.
I use it when exploring new APIs or writing fetch wrappers—cuts down on the boilerplate I’d otherwise write by hand. It’s not perfect (few tools are), but it’s faster than typing everything out, and more accurate than guessing.
If you work with JSON APIs and TypeScript daily, you might find it useful. If not, no worries—it’s just another small thing to help move code forward.
Check it out here:
👉 https://tool-json-to-typescript-converter.vercel.app
Feedback? Issues? It’s open-source on GitHub — feel free to open an issue or PR.
No hype. Just a tool I use. Hope it saves you a few minutes.
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