# @eth-optimism/message-relayer

[![codecov](https://codecov.io/gh/ethereum-optimism/optimism/branch/develop/graph/badge.svg?token=0VTG7PG7YR&flag=message-relayer-tests)](https://codecov.io/gh/ethereum-optimism/optimism)

`message-relayer` is a service that automatically finalizes ("relays") messages sent from Optimism to Ethereum.
This package is meant to be used during local development and should NOT be used on a production network.

## Installation

Clone, install, and build the Optimism monorepo:

```
git clone https://github.com/ethereum-optimism/optimism.git
yarn install
yarn build
```

## Running the relayer (Docker)

The `message-relayer` can be included as part of the [local Optimism development environment](https://community.optimism.io/docs/developers/build/dev-node/).
Although the `message-relayer` is not turned on by default, it can be enabled by [changing this line in docker-compose.yml](https://github.com/ethereum-optimism/optimism/blob/51a527b8e3fe69940fb8c0f5e4aa2e0ae8ee294c/ops/docker-compose.yml#L129) to:

```
replicas: 1
```

## Running the relayer (manual)

The `message-relayer` can also be run manually.
Copy `.env.example` into a new file named `.env`, then set the environment variables listed there.
Once your environment variables have been set, run the relayer via:

```
yarn start
```