📄️ Define Routers
To begin building your tRPC-based API, you'll first need to define your router. Once you've mastered the fundamentals, you can customize your routers for more advanced use cases.
📄️ Define Procedures
A procedure is a function which is exposed to the client, it can be one of:
📄️ Input & Output Validators
tRPC procedures may define validation logic for their input and/or output, and validators are also used to infer the types of inputs and outputs. We have first class support for many popular validators, and you can integrate validators which we don't directly support.
📄️ Merging Routers
Writing all API-code in your code in the same file is not a great idea. It's easy to merge routers with other routers.
Your context holds data that all of your tRPC procedures will have access to, and is a great place to put things like database connections or authentication information.
You are able to add middleware(s) to a procedure with the t.procedure.use() method. The middleware(s) will wrap the invocation of the procedure and must pass through its return value.
🗃️ Hosting tRPC with Adapters
📄️ Server Side Calls
You may need to call your procedure(s) directly from the same server they're hosted in, router.createCaller() can be used to achieve this.
The createContext function is called for each incoming request, so here you can add contextual information about the calling user from the request object.
📄️ Error Handling
Whenever an error occurs in a procedure, tRPC responds to the client with an object that includes an "error" property. This property contains all the information that you need to handle the error in the client.
📄️ Error Formatting
The error formatting in your router will be inferred all the way to your client (& React components)
📄️ Data Transformers
You are able to serialize the response data & input args. The transformers need to be added both to the server and the client.
Procedure metadata allows you to add an optional procedure specific meta property which will be available in all middleware function parameters.
📄️ Response Caching
The below examples uses Vercel's edge caching to serve data to your users as fast as possible.