Auth0 + fastify + tRPC

export async function buildServer() {
  const server = fastify({
    <...>
  });

  <...>

  server.register(cors, {
    <...>
  });

  await server.register(formDataPlugin);
  await server.register(ws);

  await server.register(fastifyTRPCPlugin<typeof appRouter>, {
    prefix: '/',
    useWSS: true,
    trpcOptions: {
      router: appRouter,
      createContext,
      onError({ error, req, path, input }) {
        // We use req.log.error, when available, instead of server.log.error because it will automatically add the request id to the log
        (req && req.log ? req : server).log.error({
          err: error,
          path,
          input,
        });
      },
    },
  });

  await server.register(fastifyAuth0Verify, {
    domain: '<DOMAIN>',
    audience: '<AUDIENCE>',
  });

  return server;
}

export async function createContext({ req }: CreateFastifyContextOptions) {
  await req.jwtVerify();

  const user = req.user;

  return createInnerContext({
    user,
    logger: req.log,
  });
}