openapi-ng

Generate TypeScript models and Angular services from OpenAPI 3.x specs — fast, deterministic, Rust-powered.

Try it without installing anything: playground (paste a spec, see the output) · StackBlitz demo (generated client used in an Angular app).

Documentation → · Getting started · Angular guide · Node API · Diagnostics

Why openapi-ng

• Rust-powered codegen. The engine is a native binary loaded via NAPI-RS. The same input always produces identical output.
• Angular-first output. Each operation ships with three flavors — .observable(), .resource(), .request() — matching Angular's current HTTP primitives.
• Two layouts. Per-tag @Injectable services by default, or --layout operations for one tree-shakeable constant per operation, callable from any injection context or bound once with withInjector().
• Strict OpenAPI subset. A focused 3.x slice with clear diagnostics. No silent misgeneration; see Assumptions & limitations for the accepted shape.
• Configurable naming. Tune method names and service grouping with template + regex rules, via YAML, JSON, or TypeScript config.
• Thin, pass-through helpers. Generated methods just build the request (method, URL, query, body) and forward every HttpClient.request / httpResource option through unchanged — withCredentials, transferCache, reportProgress, equal, injector, and the rest. The response reaches you untouched.

Install

bun add -d @avsystem/openapi-ng

Requires Node.js >= 22.12. Pre-built binaries for macOS, Linux (glibc and musl), and Windows (x64 / ARM64). See Runtime & platforms.

Quickstart

openapi-ng generate --input petstore.openapi.yaml --output ./generated

✓ Generated 5 files from Petstore (3.0.3)
  1 path · 1 operation · 1 schema

  model.ts
  rest.model.ts
  rest.util.ts
  rest.validate.ts
  rest/pet.rest.ts

Wire a generated service into a component:

import { Component, inject } from '@angular/core';
import { PetRest } from './generated/rest/pet.rest';

@Component({/* ... */})
export class PetList {
  readonly #pets = inject(PetRest);

  // Signal-based, reactive, with a default value while loading.
  readonly list = this.#pets.listPets.resource({ defaultValue: [] });
}

Or skip the classes. --layout operations emits one file per operation (rest/pet/list-pets.ts, rest/pet/get-pet.ts, …) plus a barrel rest/pet/index.ts, so the endpoints you never import tree-shake away:

import { Component } from '@angular/core';
import { listPets } from './generated/rest/pet';

@Component({/* ... */})
export class PetList {
  // Same three flavors; HttpClient comes from the surrounding injection context.
  readonly list = listPets.resource({ defaultValue: [] });
}

Both layouts expose the same .observable() / .resource() / .request() surface, and --layout services,operations emits the classes on top of the operation files. Details in the Angular guide.

Signal-forms async validation: rest.validate.ts

A validateRest(path, restMethod, opts) helper wraps Angular signal-forms validateAsync and delegates to the generated RequestFn.resource(), preserving request/response typing:

import { validateRest } from './generated/rest.validate';

validateRest(emailPath, accountRest.checkEmail, {
  request: ctx => ({ email: ctx.value() }),
  onError: () => ({ kind: 'email-taken' }),
});

@angular/forms is an optional peer — install it only if you import from rest.validate.ts; the file tree-shakes away when unused.

Full walkthrough on docs.openapi-ng.dev/getting-started.

Development

bun install
bun run build         # release build (Rust + NAPI)
bun run build:debug   # debug build (faster compile)
bun run test          # Node integration tests (AVA)
cargo test            # Rust unit tests
bun run lint          # oxlint
bun run format        # oxfmt + rustfmt + taplo

Rust changes require a rebuild (bun run build or bun run build:debug) before tests reflect them.

Bug reports and PRs welcome at github.com/AVSystem/openapi-ng.

License

MIT © 2026