tRPC Netlify Functions Adapter

An Adapter to run tRPC Server on Netlify Functions.

The Problem

When I'm not building with a framework (like NextJS), but into 2 separate pieces of a Client side, and a Backend running purely with Netlify Serverless Functions, I often run into cases where tRPC's Lambda Adapter cannot be fully used within the Netlify Handler, because the event object from Netlify and APIGateway Proxy event object isn't the same.

(An example of this is my Netlify Fullstack Template)

The solution

Inspired by tRPC SvelteKit and tRPC Lambda Adapter, I have created this adapter to intercept the Netlify event and convert that into a request to a pure Node server underneath for tRPC to resolve.

How to use this adapter

Install dependencies

npm install @netlify/functions @trpc/server trpc-netlify-functions

Create a tRPC Router and context

Implement your tRPC router and context. Some samples are given below. Assuming these are created in the trpc folder.

// file: trpc/router.ts
import { initTRPC } from '@trpc/server';

export const t = initTRPC.create();

export const userRouter = t.router({
  me: t.procedure.query((_req) => "hello, it's me"),
});

export const appRouter = t.router({
  users: userRouter,
});

export type AppRouter = typeof appRouter;

// file: trpc/context.ts
import { inferAsyncReturnType } from '@trpc/server';
import { CreateNetlifyContextOptions } from 'trpc-netlify-functions';

export function createContext({ event, context }: CreateNetlifyContextOptions) {
  // Empty context
  return {};
}

export type Context = inferAsyncReturnType<typeof createContext>;

Use this Netlify Functions Adapter

With Netlify Functions v1 a.k.a the Lambda Compatible Handler

Create a file called trpc.ts inside your Netlify Functions folder. Default is: [PROJECT_DIRECTORY]/netlify/functions and add the adapter in like so.

// file: netlify/functions/trpc.ts
import { netlifyTRPCHandler } from 'trpc-netlify-functions';
import { createContext } from '../../trpc/context';
import { appRouter } from '../../trpc/router';

export const handler = netlifyTRPCHandler({
  router: appRouter,
  createContext,
});

Build and deploy your code, and you can use your Netlify Functions URL to call your function.

| Endpoint | HTTP URI | | ---------- | -------------------------------------------------------------- | | users.me | GET https://<your-site-url>/.netlify/functions/trpc/users.me |