Part 2: Mount the HTTP API

Continue from Part 1. Keep Better Auth’s routes public while building your application’s API alongside them.

Describe a health endpoint

src/api.ts

import * as Schema from "effect/Schema";
import * as HttpApi from "effect/unstable/httpapi/HttpApi";
import * as HttpApiEndpoint from "effect/unstable/httpapi/HttpApiEndpoint";
import * as HttpApiGroup from "effect/unstable/httpapi/HttpApiGroup";

export class PublicApi extends HttpApiGroup.make("public").add(
  HttpApiEndpoint.get("health", "/api/health", {
    success: Schema.Struct({ ok: Schema.Boolean }),
  }),
) {}

export class AppApi extends HttpApi.make("app").add(PublicApi) {}

The schema declares the response shape. No authentication is required for this endpoint.

Implement the endpoint

src/http.ts

import * as Http from "alchemy/Http";
import * as Effect from "effect/Effect";
import * as Layer from "effect/Layer";
import * as HttpApiBuilder from "effect/unstable/httpapi/HttpApiBuilder";
import { AppApi } from "./api.ts";

const PublicLive = HttpApiBuilder.group(AppApi, "public", (handlers) =>
  handlers.handle("health", () => Effect.succeed({ ok: true })),
);

export const HttpLive = HttpApiBuilder.layer(AppApi).pipe(
  Layer.provide(PublicLive),
  Layer.provide(Http.Platform),
);

The handler supplies the declared response. Alchemy’s HTTP platform layer provides the services needed to build the API on a Worker.

Build the router

src/worker.ts

import * as HttpRouter from "effect/unstable/http/HttpRouter";
import { HttpLive } from "./http.ts";

  Effect.gen(function* () {
    yield* Auth;
    return { fetch: Effect.succeed(HttpServerResponse.text("Ready")) };
    const fetch = yield* HttpRouter.toHttpEffect(HttpLive);
    return { fetch };

Build the router once during Worker construction. Remove the now-unused HttpServerResponse import.

Mount Better Auth

src/worker.ts

import { HttpServerRequest } from "effect/unstable/http/HttpServerRequest";

  Effect.gen(function* () {
    yield* Auth;
    const auth = yield* Auth;
    const fetch = yield* HttpRouter.toHttpEffect(HttpLive);
    return { fetch };
    return {
      fetch: Effect.gen(function* () {
        const request = yield* HttpServerRequest;
        const pathname = request.url.split("?")[0];
        if (pathname === "/api/auth" || pathname.startsWith("/api/auth/")) {
          return yield* auth.fetch;
        }
        return yield* fetch;
      }),
    };

Better Auth handles its own endpoints and response cookies. Other paths go through the Effect HTTP API.

Check the public API

curl "$DEV_URL/api/health"

{"ok":true}

Check an anonymous session

curl "$DEV_URL/api/auth/get-session"

null

An anonymous request has no session. A database or authentication failure is an error, not an anonymous session.

Continue to Part 3: Build sign-in.