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

# Relayer Service

> Optional service for gasless transactions and enhanced privacy

> The relayer is **not part of the core Yona protocol**. It is an *optional external service* designed to boost privacy.

The relayer network is fully permissionless - anyone can run a relayer to process transactions and earn fees. The protocol facilitates matching between users and competing independent relayers, remaining neutral and non-custodial.

## Overview

A relayer is an intermediary service that:

* Submits transactions on behalf of users
* Pays transaction fees and nullifier costs in SOL
* Collects a service fee (see [Fees](./fees))
* Enhances privacy by decoupling submission from wallet address

This is particularly useful for users who want to withdraw or swap funds without first acquiring SOL or revealing their withdrawal address.

Check out [relayer](https://github.com/Yona-Labs/yona-privacy-app/tree/main/indexer) repository for more details.

***

## How It Works

### Transaction Flow

```
User generates ZK proof using frontend and secret message(can do it locally)
   ↓
User sends proof + withdrawal details to relayer
   ↓
Relayer validates proof structure
   ↓
Relayer submits transaction to blockchain
   ↓
Relayer pays gas fees in SOL for the transaction and nullifier costs
   ↓
User receives funds minus relayer fee 
```

### Privacy Benefits

* **No SOL Required:** Withdraw without pre-funding an address
* **Address Unlinking:** Relayer's address submits the transaction, not yours

***

## Relayer Limitations

The relayer **cannot**:

* Steal your funds (proof is cryptographically bound to the transaction data)
* Modify transaction data (proof validates exact data)
* Link deposits to withdrawals (zero-knowledge property)
* Access your private keys or UTXOs

He only can **reject** the transaction if its economically unfeasible to process it.

See [Public Inputs & Data Integrity](./technical#public-inputs--data-integrity) for more details.