Claude Code for T3 Stack tRPC Next.js Workflow

The T3 stack—built around tRPC, Next.js, TypeScript, Tailwind CSS, and Prisma—provides end-to-end type safety for modern web applications. When combined with Claude Code’s CLI capabilities, you can accelerate development workflows, maintain type safety across your codebase, and build robust full-stack applications faster than ever.

This guide explores practical ways to leverage Claude Code when building with the T3 stack, covering project setup, API development, and common troubleshooting patterns.

Setting Up Your T3 Stack Project

Claude Code can help scaffold your T3 stack project and configure the essential pieces. While the official create-t3-app CLI handles most initial setup, Claude Code excels at customizing configurations and adding new features:

# Initialize a new T3 stack project
npx create-t3-app@latest my-t3-app
cd my-t3-app

After project creation, Claude Code can help you understand the generated structure:

my-t3-app/
├── src/
│   ├── server/
│   │   ├── api/
│   │   │   ├── root.ts
│   │   │   ├── routers/
│   │   │   │   └── post.ts
│   │   │   └── trpc.ts
│   ├── utils/
│   │   └── trpc.ts
│   └── pages/
│       ├── api/
│       │   └── trpc/
│       │       └── [trpc].ts
│       └── _app.tsx
├── prisma/
│   └── schema.prisma
└── next.config.js

Building Type-Safe API Routers with tRPC

One of the T3 stack’s greatest strengths is end-to-end type safety. Claude Code can help you create routers that maintain this safety while following best practices:

// src/server/api/routers/post.ts
import { z } from "zod";
import {
  createTRPCRouter,
  publicProcedure,
  protectedProcedure,
} from "~/server/api/trpc";

export const postRouter = createTRPCRouter({
  // Public: List all posts with pagination
  getAll: publicProcedure
    .input(
      z.object({
        limit: z.number().min(1).max(100).default(10),
        cursor: z.string().nullish(),
      })
    )
    .query(async ({ ctx, input }) => {
      const limit = input.limit;
      const { cursor } = input;

      const items = await ctx.db.post.findMany({
        take: limit + 1,
        cursor: cursor ? { id: cursor } : undefined,
        orderBy: { createdAt: "desc" },
        include: { author: true },
      });

      let nextCursor: typeof cursor | undefined = undefined;
      if (items.length > limit) {
        const nextItem = items.pop();
        nextCursor = nextItem!.id;
      }

      return { items, nextCursor };
    }),

  // Protected: Create a new post
  create: protectedProcedure
    .input(
      z.object({
        title: z.string().min(1).max(280),
        content: z.string().min(1),
      })
    )
    .mutation(async ({ ctx, input }) => {
      return ctx.db.post.create({
        data: {
          title: input.title,
          content: input.content,
          authorId: ctx.session.user.id,
        },
      });
    }),
});

Consuming tRPC Endpoints in Next.js Components

When building your frontend, Claude Code can help you write type-safe queries and mutations. The tRPC hooks automatically infer types from your backend routers:

// src/pages/index.tsx
import { api } from "~/utils/trpc";

export default function Home() {
  const [posts, { isLoading }] = api.post.getAll.useQuery({
    limit: 10,
  });

  const utils = api.useUtils();
  const createPost = api.post.create.useMutation({
    onSuccess: () => {
      utils.post.getAll.invalidate();
    },
  });

  const handleSubmit = (e: React.FormEvent) => {
    e.preventDefault();
    const formData = new FormData(e.target as HTMLFormElement);
    createPost.mutate({
      title: formData.get("title") as string,
      content: formData.get("content") as string,
    });
  };

  if (isLoading) return <div>Loading posts...</div>;

  return (
    <main className="container mx-auto p-4">
      <h1 className="text-3xl font-bold mb-6">T3 Blog</h1>
      
      <form onSubmit={handleSubmit} className="mb-8">
        <input
          name="title"
          placeholder="Post title"
          className="border p-2 mr-2 rounded"
          required
        />
        <textarea
          name="content"
          placeholder="Post content"
          className="border p-2 mr-2 rounded"
          required
        />
        <button
          type="submit"
          disabled={createPost.isPending}
          className="bg-blue-500 text-white px-4 py-2 rounded"
        >
          {createPost.isPending ? "Publishing..." : "Publish"}
        </button>
      </form>

      <ul>
        {posts?.items.map((post) => (
          <li key={post.id} className="border-b py-4">
            <h2 className="text-xl font-semibold">{{ post.title }}</h2>
            <p className="text-gray-600">{{ post.content }}</p>
            <span className="text-sm text-gray-400">
              By {{ post.author.name }}
            </span>
          </li>
        ))}
      </ul>
    </main>
  );
}

Debugging Common T3 Stack Issues

Claude Code is particularly helpful when debugging type errors or configuration problems in your T3 stack application.

Resolving tRPC Type Errors

When you encounter type errors in tRPC procedures, the issue often relates to Zod schema definitions or router configuration. Here’s how to approach common scenarios:

Missing input validation: Always define input schemas using Zod
Context type mismatches: Ensure your Context type includes all required properties
Procedure type conflicts: Verify public and protected procedures have correct middleware

Fixing Next.js Build Issues

If your Next.js build fails after adding new tRPC routers:

# Clear the Next.js cache and rebuild
rm -rf .next
npm run build

Database Schema Changes

When modifying your Prisma schema, regenerate your client:

npx prisma generate
npx prisma db push

Integrating Authentication with NextAuth.js

The T3 stack typically includes NextAuth.js for authentication. Claude Code can help you configure providers and protect routes:

// src/server/auth.ts
import { PrismaAdapter } from "@next-auth/prisma-adapter";
import { type GetServerSidePropsContext } from "next";
import {
  getServerSession,
  type DefaultSession,
  type NextAuthOptions,
} from "next-auth";
import DiscordProvider from "next-auth/providers/discord";
import { env } from "~/env";
import { db } from "~/server/db";

declare module "next-auth" {
  interface Session extends DefaultSession {
    user: DefaultSession["user"] & {
      id: string;
    };
  }
}

export const authOptions: NextAuthOptions = {
  callbacks: {
    session: ({ session, user }) => ({
      ...session,
      user: {
        ...session.user,
        id: user.id,
      },
    }),
  },
  adapter: PrismaAdapter(db),
  providers: [
    DiscordProvider({
      clientId: env.DISCORD_CLIENT_ID,
      clientSecret: env.DISCORD_CLIENT_SECRET,
    }),
  ],
};

Optimizing Your Development Workflow

Here are practical tips for maximizing productivity with Claude Code and the T3 stack:

Use Claude Code’s file operations to quickly create new routers and components
Leverage type inference — let tRPC’s types guide your frontend development
Run type checks frequently: npm run typecheck catches issues early
Use tRPC’s invalidation to refresh data after mutations automatically

Conclusion

Claude Code combined with the T3 stack creates a powerful development environment where type safety flows seamlessly from your database through your API to your frontend. By understanding the core patterns—router definitions, procedure types, and frontend consumption—you can build robust full-stack applications with confidence.

The key is leveraging Claude Code not just for code generation, but as a pair programmer that understands the T3 stack’s conventions and can help you navigate the nuances of type-safe API development.

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