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

# Referrers

> Understanding the referrer fee system and how referrers earn a portion of trading fees.

## Overview

The 1st DEX uses a **referrer-based fee system**. Trading fees are collected by the protocol's `feeRecipient` address, and a portion of these fees can be shared with **referrers** who bring traders to the platform.

Every order (both maker and taker) can optionally specify a **referrer** address. If specified, the referrer receives a configurable percentage of the trading fees generated by that order.

## Fee distribution

When a trade occurs, fees are split between:

1. **Protocol fee recipient** - The main protocol treasury (set at the BookManager level)
2. **Referrer** - Optional address that receives a share of the fees (configurable per book/currency)

The referrer fee rate can be set by the protocol owner for each book and currency combination using `setReferrerFeeRate` on the BookManager.

## Using referrers

### Specifying a referrer

All order structs include a `referrer` parameter:

```solidity theme={null}
// MAKE order with referrer
Controller.make(MakeOrderParams({
    id: bookId,
    tick: tick,
    quoteAmount: amount,
    referrer: referrerAddress  // Your referrer address
}), deadline);

// TAKE order with referrer
Controller.take(TakeOrderParams({
    id: bookId,
    limitPrice: price,
    quoteAmount: amount,
    maxBaseAmount: maxBase,
    referrer: referrerAddress  // Your referrer address
}), deadline);
```

### No referrer

If you don't have a referrer, use `address(0)`:

```solidity theme={null}
referrer: address(0)  // or 0x0000000000000000000000000000000000000000
```

In this case, all fees go to the protocol fee recipient.

## Default referrer

The BookManager has a **default referrer** that is used when `address(0)` is passed as the referrer parameter. This ensures fees are always distributed appropriately even when no specific referrer is provided.

## Querying fee information

You can query referrer fee information using the subgraph:

```graphql theme={null}
query ReferrerFees {
  referrers(orderBy: totalFeesCollectedUSD, orderDirection: desc) {
    id
    totalFeesCollectedUSD
    referralCount
    feesByToken {
      token {
        symbol
      }
      totalFees
      totalFeesUSD
    }
  }
}
```

See the [Query subgraph guide](/mms-api/guides/query-subgraph) for more examples.

## Becoming a referrer

To become a referrer, simply provide your address to traders. When they include your address in their orders' `referrer` field, you'll automatically receive a share of the fees generated by their trades.

Track your earnings through the subgraph or by monitoring the `ReferrerFeePaid` events emitted by the BookManager.