> ## Documentation Index
> Fetch the complete documentation index at: https://docs.hyperlane.xyz/llms.txt
> Use this file to discover all available pages before exploring further.

# Relayer HTTP API

The relayer provides a comprehensive HTTP API for inspecting database contents and managing operations. Each endpoint below includes an interactive playground where you can test the API directly.

<Note>
  Make sure to update the server URL to match your relayer instance before testing endpoints.
</Note>

## API Endpoints

The following endpoints are available for interacting with the relayer:

### Messages API

* [Get Messages](/docs/operate/relayer/api/messages/get-messages) - Query messages by domain and nonce range in the database
* [Insert Messages](/docs/operate/relayer/api/messages/post-messages) - Add new messages to the database

### Operation Management

* [List Operations](/docs/operate/relayer/api/operations/get-operations) - View pending messages in operation queues
* [Retry Messages](/docs/operate/relayer/api/operations/post-message-retry) - Trigger retry of failed messages (resets retry count)
* [Reprocess Message](/docs/operate/relayer/api/operations/post-reprocess-message) - Re-queue messages for processing on demand

<Info>
  **Retry vs Reprocess**: Retry handles failed messages currently in the operation queues (memory), while reprocess re-queues messages from the database (storage) for processing - either already-delivered messages that need reprocessing or to allow external services to trigger message delivery instead of relying on queue backoff.
</Info>

### Data Inspection

* [Get Merkle Tree Insertions](/docs/operate/relayer/api/merkle-tree-insertions/get-merkle-tree-insertions) - Query merkle tree insertion in the database
* [Insert Merkle Tree Insertions](/docs/operate/relayer/api/merkle-tree-insertions/post-merkle-tree-insertions) - Insert merkle tree insertion

### IGP Management

* [List IGP Rules](/docs/operate/relayer/api/igp/get-igp-rules) - View current gas payment rules
* [Add IGP Rule](/docs/operate/relayer/api/igp/post-igp-rules) - Create new gas payment rules
* [Remove IGP Rules](/docs/operate/relayer/api/igp/delete-igp-rules) - Delete existing gas payment rules

<Note>
  IGP endpoints are only available when gas enforcers are configured (`mod.rs:82-83`).
</Note>

## Authentication

Most endpoints do not require authentication for read operations. Write operations may require proper API keys or authentication depending on your relayer configuration.

## Base URL

The default base URL for local development is:

```
http://localhost:9090
```

Update this to match your relayer's actual endpoint when deployed.