Generate SDK from Elysia

[gabrielgrs]

Hi everyone!

I'm building an API with Elysia and I need to generate an SDK for it. I've seen several tools that do this using openapi.json, but they all have explicit typing requirements for body, parameters, etc.

Is there a simpler way to generate all of this, using Elysia's own type API to publish on NPM?

[manimovassagh]

Elysia has a built-in Eden Treaty client that gives you end-to-end type safety without needing OpenAPI at all. This is the idiomatic way to consume an Elysia API from TypeScript.

Step 1: Export your Elysia app type

// server.ts
import { Elysia, t } from "elysia";

const app = new Elysia()
  .get("/users", () => getUsers())
  .post("/users", ({ body }) => createUser(body), {
    body: t.Object({ name: t.String(), email: t.String() }),
  })
  .listen(3000);

export type App = typeof app;

Step 2: Use Eden Treaty on the client

import { treaty } from "@elysiajs/eden";
import type { App } from "./server"; // or from your published package

const api = treaty<App>("localhost:3000");

// Fully typed - params, body, response all inferred
const { data, error } = await api.users.get();
const { data: newUser } = await api.users.post({ name: "John", email: "john@example.com" });

To publish as an SDK on npm:

1. Create a package that exports just the type and a pre-configured client:

// packages/sdk/index.ts
import { treaty } from "@elysiajs/eden";
import type { App } from "../server";

export type { App };

export function createClient(baseUrl: string) {
  return treaty<App>(baseUrl);
}

2. Publish that package — consumers get full type safety with zero codegen.

If you really need OpenAPI-based codegen (for non-TypeScript clients), use the @elysiajs/swagger plugin which generates the OpenAPI spec, then run any standard OpenAPI codegen tool (openapi-typescript, orval, etc.) against the /swagger/json endpoint.

But Eden Treaty is the much simpler path if your consumers are all TypeScript.