Building End-to-End Type-Safe APIs in Next.js with tRPC

Sep 29, 2025 |

9 minutes read

The Type Safety Gap in API Development with Next.js

Modern web development increasingly demands type safety, scalability, and developer productivity. Next.js, as a full-stack React framework, already provides a strong foundation for building applications that combine frontend and backend in one ecosystem. However, when it comes to building APIs, many developers still rely on REST or GraphQL, which often introduce unnecessary complexity and duplicate work.

REST requires manually maintaining request/response types, while GraphQL requires schema definitions and resolvers. Both approaches, while powerful, create friction between frontend and backend development. For TypeScript developers, the biggest drawback is that type definitions are not shared automatically between server and client. This disconnect leads to mismatches, bugs, and additional boilerplate.

This is where tRPC (TypeScript Remote Procedure Call) comes in. tRPC allows developers to build APIs that are end-to-end type-safe without writing REST routes or GraphQL schemas. With tRPC, both client and server use the same TypeScript definitions, ensuring that if the server changes, the client instantly knows about it. Combined with Next.js, tRPC creates a seamless developer experience for full-stack TypeScript applications.

Challenges with the Traditional Approach

1. Separate API Schemas and Client Types

In REST, backend developers define endpoints and return JSON responses. Frontend developers then create TypeScript types to consume those responses. This duplication means any backend change requires manual updates on the client. GraphQL improves this with a schema-first approach, but you still need to generate types separately from the schema.

2. Risk of Type Mismatches

Even small differences between backend responses and frontend expectations can lead to runtime errors. For instance, if the backend changes a property name from username to userName, the frontend may break silently until caught at runtime.

3. Extra Boilerplate

REST requires defining routes, request handlers, controllers, and client functions for fetching. GraphQL requires schema definitions, resolvers, and often code generation for TypeScript support. These steps slow down iteration speed and introduce maintenance overhead.

4. Slower Developer Experience

In fast-moving teams, updating APIs means communicating changes, updating schemas, regenerating types, and validating everything. This slows down the feedback loop and increases friction between backend and frontend teams.

5. Scaling Complexity

As applications grow, REST and GraphQL APIs require additional tooling for validation, authorization, and caching. These add more layers of complexity, making it harder to keep everything consistent and type-safe.

Step-by-Step Solution with tRPC

Step 1: Installing Dependencies

Install tRPC and required packages:

`
bash[Text Wrapping Break]npm install @trpc/server @trpc/client @trpc/react-query @tanstack/react-query zod[Text Wrapping Break]

Step 2: Creating a tRPC Router

Define procedures using `zod` for input validation:

`
javascript[Text Wrapping Break]// server/routers/appRouter.ts[Text Wrapping Break]import { initTRPC } from '@trpc/server';[Text Wrapping Break]import { z } from 'zod';[Text Wrapping Break][Text Wrapping Break]const t = initTRPC.create();[Text Wrapping Break][Text Wrapping Break]export const appRouter = t.router({[Text Wrapping Break]  hello: t.procedure[Text Wrapping Break]	.input(z.object({ name: z.string().nullish() }).nullish())[Text Wrapping Break]	.query(({ input }) => {[Text Wrapping Break]  	return { message: `Hello ${input?.name ?? "world"}` };[Text Wrapping Break]    }),[Text Wrapping Break]});[Text Wrapping Break][Text Wrapping Break]export type AppRouter = typeof appRouter;[Text Wrapping Break]

Step 3: Setting Up API Handler

Expose the tRPC API in Next.js API routes:

`
javascript[Text Wrapping Break]// pages/api/trpc/[trpc].ts[Text Wrapping Break]import { createNextApiHandler } from '@trpc/server/adapters/next';[Text Wrapping Break]import { appRouter } from '../../../server/routers/appRouter';[Text Wrapping Break][Text Wrapping Break]export default createNextApiHandler({[Text Wrapping Break]  router: appRouter,[Text Wrapping Break]  createContext: () => ({}),[Text Wrapping Break]});[Text Wrapping Break]

Step 4: Consuming tRPC on the Client

Use `@trpc/react-query` to call procedures directly in components:

`
Use `@trpc/react-query` to call procedures directly in components: 
javascript[Text Wrapping Break]// pages/index.tsx[Text Wrapping Break]import { trpc } from '../utils/trpc';[Text Wrapping Break][Text Wrapping Break]export default function Home() {[Text Wrapping Break]  const { data, isLoading } = trpc.hello.useQuery({ name: 'Next.js' });[Text Wrapping Break][Text Wrapping Break]  if (isLoading) return Loading...
;[Text Wrapping Break]  return {data?.message};[Text Wrapping Break]}[Text Wrapping Break]

Best Practices / Recommendations

Use Zod for Validation
Modular Routers for Scalability
Leverage React Query Features
Authentication & Authorization
Error Handling
Type Inference Everywhere
Developer Experience Tools

Next.js API solutions for faster, safer development

The Way Forward

Eliminating duplicated types between the server and the client

Providing end-to-end type safety, catching errors at compile time

Reducing boilerplate, so developers can focus on business logic

Improving scalability, thanks to modular routers and built-in validation

Enhancing performance, with React Query caching and background updates

Free Consultation

Jignesh Jadav

Sep 29 2025

Jignesh is a recognized Assistant Project Manager at iFlair Web Technologies Pvt. Ltd. Jignesh has over 9 years of industry experience, and in his career, he has managed many web development projects that have been delivered on time with high customer satisfaction. His skills include JS expertise including Angular, React, Vue.js, Mean.js, Next.js, Nuxt.js, and Full-stack tech expertise also in project planning, client communication, and team management, which are a great addition to the company's continuous development and success in the technology industry.