tRPC

APIs can be a massive headache. You change an endpoint on the backend. The frontend app breaks unexpectedly. You spend hours hunting for the mismatch. Sound familiar? This synchronization problem is common. It slows down development. It also introduces frustrating bugs. Developers have long sought a a better way. Enter tRPC. It promises to solve this very problem. It makes building APIs simple and safe.

What is tRPC?

tRPC is not a new language. It is not a new network protocol. tRPC is a clever library. It uses TypeScript's powerful features. It creates a seamless link. This link connects your server and your client. Imagine your API is just one big object. Your frontend knows its every detail. That is the magic of tRPC. It creates end-to-end typesafe APIs. This is done with almost zero effort. It feels like magic.

The Core Problem: API Type Synchronization

Modern development relies heavily on APIs. We have REST APIs. We have GraphQL APIs. These connect clients and servers. But they share a common weakness. The client and server are separate entities. They don't inherently understand each other. We use contracts to bridge this gap. For REST, we use OpenAPI or Swagger. These specifications define the API's shape. For GraphQL, we have schemas. These tools work, but they add extra steps. You must constantly regenerate types. A small server change requires a build step. Forgetting this step leads to runtime errors. This process is fragile. It is also time-consuming. It adds friction to your workflow. tRPC asks a simple question. What if we could remove this step entirely?

How tRPC Works Its Magic

tRPC's approach feels like a superpower. It abandons complex build processes. It relies on something you already have. It uses TypeScript itself. The process is brilliantly simple.

First, you define your API on the server. You create a router. This router holds all your API endpoints. These endpoints are called procedures. A procedure can be a query. It can be a mutation. Or it can be a subscription. You write them as simple TypeScript functions.

// server/router.ts
import { initTRPC } from '@trpc/server';
import { z } from 'zod';

const t = initTRPC.create();

export const appRouter = t.router({
  userById: t.procedure
    .input(z.string())
    .query((opts) => {
      const { input } = opts;
      // Fetch user from a database...
      return { id: input, name: 'Bilbo Baggins' };
    }),
});

// We only export the *type* of the router
export type AppRouter = typeof appRouter;

Notice we use Zod for input validation. This ensures data from the client is correct. Then, we export one crucial thing. It is type AppRouter. We do not export any server code. We only export the type definition. This is the secret sauce.

Next, you import this type on the client. The tRPC client library uses this type. It automatically knows everything about your API. It knows procedure names. It knows their required inputs. It knows their expected outputs.

// client/app.tsx
import { createTRPCReact } from '@trpc/react-query';
import type { AppRouter } from '../server/router';

const trpc = createTRPCReact<AppRouter>();

function MyComponent() {
  const userQuery = trpc.userById.useQuery('123');
  
  if (userQuery.isLoading) {
    return <div>Loading...</div>
  }
  
  // userQuery.data is fully typed!
  // TypeScript knows data is { id: string; name: string; }
  return <div>Welcome, {userQuery.data?.name}</div>;
}

That's it. There is no code generation. There is no compilation step. The type safety is instantaneous. Your IDE becomes your API documentation.

Key Benefits That Supercharge Development

tRPC offers many incredible benefits. They all lead to a superior experience. You can move faster. And you can do it with more confidence.

End-to-End Typesafety

This is the main event. True end-to-end typesafety is a game-changer. Let's say you refactor the backend. You rename userById to getUser. Instantly, your client-side code breaks. TypeScript will show a clear error. It will say userById does not exist. You fix it directly in your IDE. Now, let's change the output data. The user object now includes an email. Your frontend code remains valid. But what if you remove the name field? Your client code will immediately error. TypeScript will tell you name no longer exists. This feedback loop is immediate. It happens before you even save the file. Bugs are caught at compile time, not runtime. This eliminates an entire class of common errors.

Unmatched Developer Experience (DX)

Forget checking Postman or API docs. Your editor is all you need. When you type trpc., you get a list. It shows all available procedures. trpc.userById... autocompletes. Then you type .useQuery(. The IDE tells you the exact input type. It knows a string is expected. You cannot pass a number by mistake. Hover over the query's result. You see the exact return type. This flawless autocompletion feels magical. It makes development fast and intuitive. You spend less time guessing. You spend more time building great features.

No Code Generation, No Build Steps

This benefit cannot be overstated. Traditional API workflows have friction. You change a GraphQL schema. Then you must run a codegen script. This generates new TypeScript types. This process takes time. It can break easily. It complicates your CI/CD pipeline. tRPC has absolutely no build steps. The type inference is instant. The connection is live. This simplifies your toolchain dramatically. It makes your development loop much faster. The result is a snappier, more enjoyable process.

Lightweight and Framework Agnostic

Under the hood, tRPC is simple. It is mostly function calls. They are sent over standard HTTP. There are zero dependencies in the core client. The bundle size impact is tiny. This is great for web performance. It is also fully framework agnostic. While it shines with Next.js, it works anywhere. There are adapters for React and React Query. You can find them for Solid, Svelte, and Vue. On the backend, you have adapters. Use Express, Fastify, or AWS Lambda. This flexibility is a huge advantage. You can adopt tRPC in your existing stack.

tRPC vs. The Alternatives

How does tRPC compare to others? It's important to know its place. It is not a replacement for everything.

vs. REST

REST is the industry standard. It's robust and platform-independent. But it lacks a formal type contract. Developers use tools like OpenAPI. This generates documentation and client types. This works, but it's a manual process. You must keep the specification updated. tRPC makes the code the single source of truth. There is no separate spec to maintain. The types are always, automatically, in sync. This is a massive improvement for full-stack apps.

vs. GraphQL

GraphQL is incredibly powerful. It allows clients to request specific data. This helps a lot with over-fetching. It's excellent for public APIs. Many different clients can consume them. However, GraphQL has complexity. You need to define a schema. You have to write resolvers. You must set up a code generation step. tRPC is far simpler for its use case. It is designed for client-server pairs. Think of a web app and its dedicated backend. When you control both, tRPC shines. It offers similar typesafety to GraphQL. But it has far less boilerplate to manage.

Downsides and Considerations

tRPC is not a silver bullet. Every tool has tradeoffs. It's important to understand them.

First, tRPC is for TypeScript projects. Its magic comes from TypeScript's static inference. If your project isn't using TypeScript, tRPC is not for you. This is its core design.

Second, it creates a tight coupling. The client and server are closely linked. This is its greatest strength. It is also its main limitation. tRPC is not ideal for public APIs. Third-party developers cannot easily consume it. They would need access to your router's types. For public APIs, REST or GraphQL are better choices. They offer a standard, decoupled interface.

Finally, remember it is not a new protocol. It uses standard HTTP POST/GET requests. The "RPC" part describes a programming style. You are calling server functions from the client. This is an implementation detail. But it is helpful to know.

Conclusion: Is tRPC Right for You?

So, should you use tRPC? The answer depends on your project.

Are you building a full-stack application with TypeScript? Is your team an in-house team? Do you control both the frontend and backend? If you answered "yes" to these questions, then tRPC is a phenomenal choice. It is likely the best tool for the job.

tRPC delivers on its promise. "Move Fast and Break Nothing." It dramatically improves the developer experience. It makes your code more robust. It eliminates an entire category of common bugs. It simplifies your toolchain and build process. It lets you focus on what truly matters. Building great products for your users. If you are in the TypeScript ecosystem, give tRPC a try. You will not be disappointed. It might just change how you think about APIs forever.