Configuration

The @robojs/trpc plugin has no configuration options of its own. Its behavior is determined by @robojs/server's prefix setting and the files seeded into your project.

Server prefix

The plugin detects @robojs/server's prefix option at startup and registers the tRPC endpoint at {prefix}/trpc.

export default {
	prefix: '/api' // default
}

export default {
	prefix: '/api' // default
}

The client's httpBatchLink URL must match this endpoint. See the client guide for details.

Seed files

When installed via npx robo add @robojs/trpc, three files are seeded into your project:

All three files are required for the plugin to function. The start hook is especially critical — without it, the router is never registered and all API calls fail.

Dependencies

Required

Optional

Bundled

These are included with the plugin — no need to install separately:

API reference

Server exports

Exported from @robojs/trpc/server.js:

Client exports

Exported from @robojs/trpc:

Components

Client creation

Links

Error classes

Utilities

Types

Troubleshooting

"Router is not registered"

This error means the tRPC router was never captured by the plugin. Common causes:

Wrong initTRPC import. Import from @robojs/trpc/server.js, not @trpc/server:

// Correct
import { initTRPC } from '@robojs/trpc/server.js'

// Wrong — bypasses router registration
import { initTRPC } from '@trpc/server'

// Correct
import { initTRPC } from '@robojs/trpc/server.js'

// Wrong — bypasses router registration
import { initTRPC } from '@trpc/server'

Missing start hook. Make sure src/robo/start/trpc.ts exists and imports your server file:

export default () => import('../../trpc/server.js')

export default () => import('../../trpc/server.js')

Router not called. The server file must call t.router() — defining the router is what triggers registration.

404 errors on tRPC calls

The client URL doesn't match the server prefix. If @robojs/server uses a custom prefix, update the httpBatchLink URL:

// If server prefix is '/v1':
httpBatchLink({ url: '/v1/trpc' })

// If server prefix is '' (empty):
httpBatchLink({ url: '/trpc' })

// If server prefix is '/v1':
httpBatchLink({ url: '/v1/trpc' })

// If server prefix is '' (empty):
httpBatchLink({ url: '/trpc' })

TypeScript errors on client

Make sure your server file exports the AppRouter type:

export type AppRouter = typeof appRouter

And the client imports it as a type:

import type { AppRouter } from './server'

Missing @robojs/server

The plugin requires @robojs/server for HTTP routing. Install both together:

npx robo add @robojs/server@next @robojs/trpc@next

Next Steps