# Interface: TRPCRouterBuilder()<TRoot>

> 

Defined in: [packages/server/src/unstable-core-do-not-import/router.ts:207](https://github.com/trpc/trpc/blob/7c907acfd8b31929214792e3b8c2ad7a8ac72563/packages/server/src/unstable-core-do-not-import/router.ts#L207)

The type of `t.router()`.

## See

https://trpc.io/docs/server/routers

## Type Parameters

| Type Parameter |
| ------ |
| `TRoot` *extends* [`AnyTRPCRootTypes`](https://trpc.io/docs/typedoc/server/index/type-aliases/AnyTRPCRootTypes.md) |

> **TRPCRouterBuilder**\<`TIn`\>(`_`): [`TRPCBuiltRouter`](https://trpc.io/docs/typedoc/server/index/type-aliases/TRPCBuiltRouter.md)\<`TRoot`, `DecorateCreateRouterOptions`\<`TIn`\>\>

Defined in: [packages/server/src/unstable-core-do-not-import/router.ts:208](https://github.com/trpc/trpc/blob/7c907acfd8b31929214792e3b8c2ad7a8ac72563/packages/server/src/unstable-core-do-not-import/router.ts#L208)

The type of `t.router()`.

## Type Parameters

| Type Parameter |
| ------ |
| `TIn` *extends* `CreateRouterOptions` |

## Parameters

| Parameter | Type |
| ------ | ------ |
| `_` | `TIn` |

## Returns

[`TRPCBuiltRouter`](https://trpc.io/docs/typedoc/server/index/type-aliases/TRPCBuiltRouter.md)\<`TRoot`, `DecorateCreateRouterOptions`\<`TIn`\>\>

## See

https://trpc.io/docs/server/routers