# IPeripheryImmutableState

Functions that return immutable state of the router

### Functions[​](https://docs.uniswap.org/contracts/v3/reference/periphery/interfaces/IPeripheryImmutableState#functions) <a href="#functions" id="functions"></a>

#### factory[​](https://docs.uniswap.org/contracts/v3/reference/periphery/interfaces/IPeripheryImmutableState#factory) <a href="#factory" id="factory"></a>

```solidity
  function factory(
  ) external returns (address)
```

**Return Values:**[**​**](https://docs.uniswap.org/contracts/v3/reference/periphery/interfaces/IPeripheryImmutableState#return-values)

| Type    | Description                           |
| ------- | ------------------------------------- |
| address | the address of the Uniswap V3 factory |

#### WETH9[​](https://docs.uniswap.org/contracts/v3/reference/periphery/interfaces/IPeripheryImmutableState#weth9) <a href="#weth9" id="weth9"></a>

```solidity
  function WETH9(
  ) external returns (address)
```

**Return Values:**[**​**](https://docs.uniswap.org/contracts/v3/reference/periphery/interfaces/IPeripheryImmutableState#return-values-1)

| Type    | Description          |
| ------- | -------------------- |
| address | the address of WETH9 |


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://bonsaiswap.gitbook.io/bonsaiswap-docs/developers/technical-reference/periphery/interfaces/iperipheryimmutablestate.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.