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

# RelayData

> MEV relay connection information for Proposer-Builder Separation (PBS)

# RelayData

MEV relay connection information for Proposer-Builder Separation (PBS).

## Overview

RelayData represents MEV relay connection information used in PBS. Relays act as trusted intermediaries between block builders and validators, ensuring builders cannot see validator signatures before block delivery.

## Type Definition

```typescript theme={null}
type RelayDataType = {
  /** MEV relay endpoint URL */
  readonly relayUrl: string;

  /** Relay's BLS public key (48 bytes) */
  readonly relayPubkey: Uint8Array;

  /** Builder's BLS public key (48 bytes, optional) */
  readonly builderPubkey?: Uint8Array;

  /** Current consensus layer slot */
  readonly slot: SlotType;

  /** Parent block hash (32 bytes) */
  readonly parentHash: HashType;

  /** Validator fee recipient address (20 bytes) */
  readonly proposerFeeRecipient: AddressType;
};
```

## Well-Known Relays

```typescript theme={null}
import { MEV_RELAYS } from './primitives/RelayData/index.js';

MEV_RELAYS.FLASHBOTS          // "https://relay.flashbots.net"
MEV_RELAYS.BLOXROUTE_MAX_PROFIT  // "https://bloxroute.max-profit.bloxroute.com"
MEV_RELAYS.BLOXROUTE_REGULATED   // "https://bloxroute.regulated.bloxroute.com"
MEV_RELAYS.EDEN               // "https://relay.edennetwork.io"
MEV_RELAYS.MANIFOLD           // "https://mainnet-relay.securerpc.com"
MEV_RELAYS.ULTRASOUND         // "https://relay.ultrasound.money"
MEV_RELAYS.AGNOSTIC           // "https://agnostic-relay.net"
```

## Usage

### Create RelayData

```typescript theme={null}
import * as RelayData from './primitives/RelayData/index.js';
import { MEV_RELAYS } from './primitives/RelayData/index.js';

const relay = RelayData.from({
  relayUrl: MEV_RELAYS.FLASHBOTS,
  relayPubkey: new Uint8Array(48), // relay's BLS pubkey
  slot: 12345n,
  parentHash: new Uint8Array(32),
  proposerFeeRecipient: "0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266",
});
```

### Get API Endpoint

```typescript theme={null}
const url = RelayData.getEndpoint(relay, "/eth/v1/builder/header");
// "https://relay.flashbots.net/eth/v1/builder/header"
```

## API Reference

### Constructors

| Function     | Description                      |
| ------------ | -------------------------------- |
| `from(data)` | Create from RelayDataLike object |

### Methods

| Function                     | Description                     |
| ---------------------------- | ------------------------------- |
| `getEndpoint(relay, method)` | Construct full API endpoint URL |

### Constants

| Constant     | Description                |
| ------------ | -------------------------- |
| `MEV_RELAYS` | Well-known relay endpoints |

## MEV-Boost API Endpoints

Common relay API methods:

| Endpoint                         | Description              |
| -------------------------------- | ------------------------ |
| `/eth/v1/builder/header`         | Request block header bid |
| `/eth/v1/builder/blinded_blocks` | Submit blinded block     |
| `/eth/v1/builder/status`         | Check relay status       |
| `/relay/v1/data/bidtraces`       | Query bid traces         |

### Example: Request Block Header

```typescript theme={null}
const endpoint = RelayData.getEndpoint(relay, "/eth/v1/builder/header");
const params = `${relay.slot}/${relay.parentHash}/${relay.proposerFeeRecipient}`;

const response = await fetch(`${endpoint}/${params}`);
const bid = await response.json();
```

## PBS Flow

```
Builder                    Relay                      Proposer
   |                         |                            |
   |--[submit block bid]---->|                            |
   |                         |--[header+bid]------------->|
   |                         |                            |
   |                         |<--[signed header]----------|
   |                         |                            |
   |<--[request payload]-----|                            |
   |--[block payload]------->|                            |
   |                         |--[full block]------------->|
```

1. **Builder** submits block bid to relay
2. **Relay** forwards best header to proposer
3. **Proposer** signs header (commits to block)
4. **Relay** releases block to builder
5. **Builder** sends full payload
6. **Relay** forwards to proposer for broadcast

## Relay Selection

Consider when selecting relays:

* **Censorship**: Some relays filter transactions (OFAC compliance)
* **Reputation**: Relay uptime and reliability
* **Diversity**: Using multiple relays reduces centralization risk
* **Geographic**: Latency affects bid competitiveness

```typescript theme={null}
// Use multiple relays for redundancy
const relays = [
  RelayData.from({ relayUrl: MEV_RELAYS.FLASHBOTS, ... }),
  RelayData.from({ relayUrl: MEV_RELAYS.ULTRASOUND, ... }),
  RelayData.from({ relayUrl: MEV_RELAYS.AGNOSTIC, ... }),
];
```

## See Also

* [Slot](/primitives/slot) - Consensus layer slot
* [Hash](/primitives/hash) - Hash primitive
* [Address](/primitives/address) - Ethereum address
* [BLS12-381](/crypto/bls12-381) - BLS signatures