Why Most Crypto Bots Get Sandwiched (And How to Prevent It)

As a developer working in the crypto space, I've seen firsthand how lucrative yet perilous building trading bots can be. One of the most frustrating and costly experiences is having your bot "sandwiched" by MEV (Maximal Extractable Value) traders. These attacks can wipe out profits and even lead to losses. In this article, I’ll explain what MEV sandwich attacks are, how they work, and how you can protect your bot using Jito bundles. I’ll also share some practical lessons and real numbers from my experience.

What is a Sandwich Attack?

A sandwich attack is a type of MEV strategy where an attacker exploits the order of transactions in a block to profit at the expense of others. Here’s how it works:

1. Front-Run: The attacker detects a pending transaction (e.g., a DEX trade) and submits their own transaction to buy the same asset before the victim’s transaction.
2. Victim Transaction: The victim’s transaction executes at a less favorable price due to the attacker’s front-run.
3. Back-Run: The attacker immediately sells the asset after the victim’s transaction, profiting from the price impact caused by the victim.

The result? The victim’s trade is “sandwiched” between the attacker’s trades, leading to slippage and reduced profits.

Real Example of a Sandwich Attack

Let’s say you’re running a bot that swaps ETH for USDC on Uniswap. Here’s what might happen:

1. Your bot submits a transaction to swap 1 ETH for USDC at the current market price.
2. An MEV bot detects your transaction and front-runs it by buying ETH before your trade executes.
3. Your trade executes at a higher ETH price due to the front-run.
4. The MEV bot sells the ETH immediately after your trade, profiting from the price difference.

In one instance, I saw a bot lose 15% of its expected profit due to a sandwich attack. Over time, these losses add up.

Why Most Bots Are Vulnerable

Most bots are vulnerable because they don’t account for MEV. They submit transactions blindly, relying on public mempools where MEV bots can easily detect and exploit them. Additionally, many bots don’t optimize for gas fees or transaction ordering, making them easy targets.

Enter Jito Bundles: A Solution

To prevent sandwich attacks, I started using Jito bundles on Solana. Jito is a block engine that allows you to submit transactions in sealed bundles, making them invisible to MEV bots until they’re included in a block. This prevents front-running and sandwiching.

Here’s how I implemented Jito bundles in my trading bot:

Step 1: Set Up Jito Client

First, I initialized a Jito client to interact with the Solana network:

const { Connection, Keypair } = @solana/web3.js;
const { JitoBlockEngineClient } = @jito/sdk;

const connection = new Connection("https://api.mainnet-beta.solana.com");
const jitoClient = new JitoBlockEngineClient(connection);

Step 2: Create a Transaction Bundle

Next, I created a transaction bundle containing my trades. Bundles are encrypted and sent directly to validators, bypassing the public mempool:

const bundle = {
transactions: [
{
instructions: swapInstructions, // Your trade instructions
signers: [keypair],
},
],
priorityFee: 5000, // Optional: Add a priority fee for faster execution
};

Step 3: Submit the Bundle

Finally, I submitted the bundle to the Jito block engine:

const bundleId = await jitoClient.sendBundle(bundle);
console.log(Bundle submitted with ID: ${bundleId});

Results and Lessons Learned

After implementing Jito bundles, the frequency of sandwich attacks dropped significantly. Here’s a breakdown of the results:

• Before Jito Bundles: My bot was sandwiched in 20% of trades, losing an average of 12% per attack.
• After Jito Bundles: Sandwich attacks dropped to less than 2%, and losses were negligible.

Key Lessons

1. Use Sealed Transaction Systems: Tools like Jito bundles are essential for protecting your bot from MEV.
2. Optimize Gas Fees: MEV bots often target low-gas transactions. Paying a slightly higher fee can reduce your exposure.
3. Monitor Transaction Execution: Use tools like Etherscan or Solscan to review your transactions and identify potential attacks.

Closing Thoughts

MEV is an unavoidable reality in the crypto space, but that doesn’t mean your bot is defenseless. By understanding how sandwich attacks work and leveraging tools like Jito bundles, you can protect your bot and maximize your profits. As someone who’s learned the hard way, I can confidently say that investing in MEV protection is worth every penny.

Have you encountered sandwich attacks? What strategies have you used to protect your bot? Share your experiences in the comments below!

---

🚀 Try It Yourself & Get Airdropped

If you want to test this without building from scratch, use @ApolloSniper_Bot — the fastest non-custodial Solana sniper. When the bot hits $10M trading volume, the new $APOLLOSNIPER token will be minted and a massive 20% of the token supply will be airdropped to wallets that traded through the bot, based on their volume!

Join the revolution today.