Free TypeScript Developer Tool

Generate TypeScript Interfaces
from Multiple JSONs at Once

TypeLoom analyzes all your API payloads simultaneously — GET responses, POST bodies, PUT requests — and outputs clean, deduplicated interfaces with automatic extends detection. In real time.

Free forever  ·  No login  ·  No install  ·  Runs in your browser

Other tools

Only handle one JSON at a time. Paste GET response → get flat interface. Paste POST body → different file, zero awareness of shared structures.

You end up with 5 duplicate { id, name } interfaces and no extends anywhere.

TypeLoom

Accepts all your payloads at once. Finds that Type should extendsFrom. Detects that PokemonResponse extends CreatePokemonRequest. Emits one clean, ordered file.

Everything you need, nothing you don't

Built specifically for the real-world workflow of Angular and NestJS developers.

Multi-JSON inputs

Paste as many JSON payloads as you need — GET responses, POST bodies, PUT requests — all at once.

Extends detection

Automatically detects when one interface is a superset of another and emits the correct extends relationship.

Deduplication

Identical nested structures across all your inputs are merged into a single shared interface with a usage comment.

Real-time generation

Output updates as you type. No submit button, no waiting — built with Angular Signals and computed().

Topological order

Base interfaces are always emitted before the ones that depend on them. Ready to paste, zero manual reordering.

Free forever

No account. No API key. No limits. Runs entirely in your browser. Support it with a Ko-fi if it saves you time.

How it works

Three steps to production-ready TypeScript interfaces.

Paste your JSONs

Add one card per endpoint — GET response, POST body, anything. Give each one a meaningful interface name.

TypeLoom analyzes

The engine walks all inputs, extracts nested objects, computes signatures, and resolves shared structures and inheritance.

Copy & use

Hit Copy, paste into your Angular service or NestJS DTO file. Rename shared types if needed — you're done.

Free forever. Supported by the community.

TypeLoom is completely free — no account, no limits, no API key. If it saves you time, a coffee goes a long way toward keeping it running and improving.