djDaloyJS

Search docs

Jump between documentation pages.

Browse docs

Typed clients

DaloyJS ships two ways to call your API with full type-safety. Use whichever fits your consumer.

1. In-process typed client (zero codegen)

For TypeScript consumers in the same monorepo (tests, internal tools, Next.js server actions):

ts
import { createClient } from "@daloyjs/core/client";
    import { app } from "./server.js"; // your App instance

const client = createClient(app, { baseUrl: "http://localhost:3000" });

const r = await client.getBookById({ params: { id: "1" } });
//    ^? { status: 200; body: { id: string; title: string } }
//      | { status: 404; body: ProblemJson }

if (r.status === 200) {
  console.log(r.body.title); // string, fully typed
}

The client is keyed by operationId, returns a discriminated union of {status, body, headers}, and infers everything from the route definition itself. No build step.

2. Hey API SDK (cross-language, cross-repo, build-time)

For consumers outside the monorepo or in other languages, generate a fully typed fetch SDK with @hey-api/openapi-ts.

bash
pnpm add -D @hey-api/openapi-ts
ts
// openapi-ts.config.ts
import { defineConfig } from "@hey-api/openapi-ts";

export default defineConfig({
  input: "./generated/openapi.json",
  output: { path: "./generated/client", format: "prettier" },
  plugins: ["@hey-api/client-fetch", "@hey-api/typescript", "@hey-api/sdk"],
});
json
// package.json
"scripts": {
  "gen:openapi": "node --import tsx/esm scripts/dump-openapi.ts",
  "gen:client":  "openapi-ts",
  "gen":         "pnpm gen:openapi && pnpm gen:client"
}
bash
pnpm gen
# writes:
#   generated/openapi.json
#   generated/client/{client.gen.ts, sdk.gen.ts, types.gen.ts, index.ts}

Using the generated SDK

ts
import { client } from "./generated/client";
import { getBookById } from "./generated/client/sdk.gen";

client.setConfig({ baseUrl: "https://api.example.com" });

const { data, error } = await getBookById({ path: { id: "1" } });
if (error) console.error(error);
else console.log(data.title);

Which one should I use?

Use casePick
Same-repo TypeScript caller (tests, internal tools)In-process createClient
Web app / mobile RN bundle in a separate repoHey API SDK
Non-TypeScript consumer (Python, Swift, Kotlin)OpenAPI doc + their preferred generator
Public SDK for third partiesHey API SDK, published as its own package

Need a bigger contract to validate your generator output? Use the large fake REST demo as the stress case instead of a minimal tutorial app.