Effect procedures

Use .effect(...) when a procedure implementation should run as an Effect. Handlers can be generator callbacks, Effect.fn(...) callbacks, or functions that return an Effect.

effect-procedure.ts

const getUser = effectProcedure
  .input(z.object({ id: z.string() }))
  .effect(function* ({ input }) {
    const user = yield* UsersRepo.findById(input.id);
    return user;
  });

The handler receives the normal oRPC handler options, including input, context, errors, path, signal, and metadata.

Handler shape

handler-options.ts

const procedure = effectProcedure.effect(function* ({
  input,
  context,
  errors,
  path,
  signal,
}) {
  yield* Effect.logDebug("handling procedure", { path });

  if (signal?.aborted) {
    yield* Effect.logDebug("request was already aborted");
  }

  return { input, context, path, errorKeys: Object.keys(errors) };
});

Effect-returning handlers

Use a plain Effect-returning callback when you already have an Effect value, or when you want to keep a named Effect.fn(...) span inside the automatic procedure span.

effect-returning.ts

const getUser = effectProcedure.effect(
  Effect.fn("users.get")(function* ({ input }) {
    return yield* UsersRepo.findById(input.id);
  }),
);

const listUsers = effectProcedure.effect(() =>
  Effect.gen(function* () {
    return yield* UsersRepo.list();
  }),
);

Mix with standard oRPC handlers

You can put standard oRPC procedures and Effect procedures in the same router.

mixed-router.ts

import { os } from "@orpc/server";

export const router = {
  health: os.handler(() => "ok"),

  users: {
    get: effectProcedure.effect(function* ({ input }) {
      return yield* UsersRepo.findById(input.id);
    }),
  },
};

Use .handler(...) for plain synchronous or async procedures. Use .effect(...) when the handler needs Effect services, typed Effect failures, tracing, or fiber context.

Next steps

Add schemas with Input and output schemas.
Add services with Service injection.

Getting started

Capabilities

Guides

Reference

Help

Handler shape

Effect-returning handlers

Mix with standard oRPC handlers

Next steps

​Handler shape

​Effect-returning handlers

​Mix with standard oRPC handlers

​Next steps

Handler shape

Effect-returning handlers

Mix with standard oRPC handlers

Next steps