---
title: "MEV Protection"
description: "Protect your transactions from MEV attacks"
category: "security"
keywords: ["mev", "frontrunning", "sandwich", "flashbots"]
order: 2
---
# MEV Protection
MEV (Maximal Extractable Value) refers to the profit that can be extracted from blockchain users by reordering, inserting, or censoring transactions.
## Types of MEV Attacks
### Frontrunning
An attacker sees your pending transaction and submits a similar transaction with higher gas to execute first.
**Example**: You submit a large swap on Uniswap. A bot sees this, buys the token before you (raising the price), then sells after your trade.
### Sandwich Attack
Your transaction gets "sandwiched" between two attacker transactions.
```
1. Attacker buys token (price goes up)
2. Your swap executes at worse price
3. Attacker sells token (profits from price difference)
```
### Backrunning
Attacker executes immediately after your transaction to capitalize on price changes.
## Protection Strategies
### 1. Private Mempools
Send transactions directly to block builders, bypassing the public mempool.
```typescript
import { sendPrivateTransaction } from '@universal-crypto-mcp/security';
const result = await sendPrivateTransaction({
chainId: 1,
signedTransaction: signedTx,
provider: 'flashbots', // or 'mevblocker'
});
console.log(`Included in block: ${result.blockNumber}`);
```
### 2. Flashbots Protect RPC
Use Flashbots Protect as your RPC endpoint:
```bash
# Replace your Ethereum RPC with Flashbots Protect
ETHEREUM_RPC_URL=https://rpc.flashbots.net
```
Or configure in code:
```typescript
import { createWalletClient, http } from 'viem';
import { mainnet } from 'viem/chains';
const client = createWalletClient({
chain: mainnet,
transport: http('https://rpc.flashbots.net'),
});
```
### 3. Slippage Protection
Set appropriate slippage limits:
```typescript
// Calculate minimum output
const minOutput = expectedOutput * (1 - slippage / 100);
const swap = await uniswap.swap({
tokenIn: 'ETH',
tokenOut: 'USDC',
amount: '10.0',
slippage: 0.5, // 0.5% max slippage
minOutput, // Explicitly set minimum
});
```
### 4. Deadlines
Set transaction deadlines to prevent stale transactions:
```typescript
const deadline = Math.floor(Date.now() / 1000) + 300; // 5 minutes
const swap = await uniswap.swap({
// ... other params
deadline,
});
```
### 5. Commit-Reveal Schemes
For high-value trades, use commit-reveal:
```typescript
// Step 1: Commit (hash of your intent)
const commitment = keccak256(encodePacked(
['address', 'uint256', 'bytes32'],
[recipient, amount, secret]
));
await contract.commit(commitment);
// Step 2: Wait for commitment to be included
await waitForBlocks(1);
// Step 3: Reveal and execute
await contract.reveal(recipient, amount, secret);
```
## MEV on Different Chains
| Chain | MEV Risk | Protection |
|-------|----------|------------|
| Ethereum | 🔴 High | Flashbots, MEV Blocker |
| Arbitrum | 🟡 Medium | Sequencer ordering |
| Base | 🟡 Medium | Sequencer ordering |
| Optimism | 🟡 Medium | Sequencer ordering |
| Polygon | 🟡 Medium | FastLane |
| Solana | 🟢 Low | Jito bundles |
## Detecting MEV Attacks
### Analyze Past Transactions
```typescript
import { analyzeMEV } from '@universal-crypto-mcp/security';
const analysis = await analyzeMEV({
txHash: '0x...',
chainId: 1,
});
if (analysis.wasAttacked) {
console.log(`Attack type: ${analysis.attackType}`);
console.log(`Loss: $${analysis.estimatedLoss}`);
console.log(`Attacker: ${analysis.attackerAddress}`);
}
```
### Monitor for Suspicious Activity
```typescript
import { monitorMEV } from '@universal-crypto-mcp/security';
const monitor = await monitorMEV({
address: '0xYourAddress',
onAttack: (attack) => {
console.log(`MEV attack detected: ${attack.type}`);
// Send alert
},
});
```
## Best Practices
1. **Use private transaction submission** for large trades
2. **Set tight slippage limits** (0.5% or less for stablecoins)
3. **Use L2s** for smaller trades (sequencer ordering reduces MEV)
4. **Split large orders** into smaller trades
5. **Use limit orders** instead of market orders when possible
6. **Time transactions** during low-activity periods
## Tools & Resources
- [Flashbots Protect](https://protect.flashbots.net/)
- [MEV Blocker](https://mevblocker.io/)
- [EigenPhi](https://eigenphi.io/) - MEV analysis
- [Flashbots Dashboard](https://explore.flashbots.net/)
## See Also
- [Security Overview](./overview.md)
- [Transaction Simulation](./simulation.md)
- [Best Practices](./best-practices.md)
