Frontrunning in Crypto — What It Is and How It Works

Frontrunning is when an actor sees a profitable trade you're about to make and executes the same trade before you do. Your alpha — your idea — gets captured by someone faster.

It's the oldest form of market abuse in finance, and it shows up in every crypto venue, in different shapes.

On-chain frontrunning

The classic on-chain frontrunner watches the public mempool (Ethereum) or pre-block visibility streams like Shreds (Solana), spots a profitable transaction, and submits a copy with a higher fee or priority bid so it lands first.

Common targets:

• NFT mint transactions — frontrun a mint on a hot drop.
• DEX listings — buy a token the moment it's listed, before retail.
• Liquidation transactions — beat another searcher to a liquidation.
• Arbitrage opportunities — copy another searcher's arb tx.

CEX frontrunning

On centralized exchanges, frontrunning is harder for outsiders (no public order book of pending orders) but historically did happen via:

• Insider order flow. Exchange staff seeing client orders and trading ahead of them.
• Listing announcements. Buying tokens before public listing announcements.
• Wash-trade ring leaks. Small exchanges trading against their own customers.

These are usually illegal, prosecuted as market manipulation or insider trading, and not what crypto-native discussions mean by "frontrunning."

Frontrunning vs. sandwich attacks

People often conflate them. The difference:

	Frontrunning	Sandwich attack
Goal	Capture victim's alpha	Capture victim's slippage
Number of attacker txs	1 (in front)	2 (in front + behind)
Victim outcome	Their tx may revert or succeed at unchanged price	Their tx fills at a worse price
Profit source	The trade idea itself	The price movement the victim caused

A sandwich is a superset of frontrunning — it includes a frontrun tx but also a backrun.

Frontrunning on Solana specifically

Without a public mempool, traditional frontrunning on Solana looks different. The visible-in-advance window comes from:

• Shreds — partial block data the leader broadcasts before the block is final.
• Validator-level pre-execution — some validators offer this as a paid service to searchers.

This makes Solana frontrunning possible but harder than on Ethereum, and dependent on infrastructure access.

How to protect yourself

If you're a regular user, not a searcher:

• Use private order flow. Flashbots Protect on Ethereum, Jito-bundled submission on Solana — both keep your tx invisible until included.
• Use a routing API that defaults to private submission. Venum's /v1/swap (and /v1/bundle for atomic Jito bundles) does this for Solana swaps.
• Don't telegraph trades. Posting on X "I'm about to ape into $TOKEN" with the tx in the next block is begging to be frontrun. Some "alpha leakers" are doing it on purpose.
• For NFT mints, use bundle services or wait out the first-block frenzy.

Read next

• MEV Overview → — section index
• Sandwich Attack → — frontrunning's evil twin
• Backrunning → — the inverse: trading right after someone else
• MEV Searchers → — who runs these bots

FAQ

Is frontrunning illegal in crypto?

On centralized exchanges (with insider info): generally illegal as market manipulation. On-chain via public mempool / Shreds: legally murky in most places — operates on permissionless infrastructure but increasingly draws regulatory attention.

Can I prevent all frontrunning?

Not entirely, but you can make yourself unprofitable to frontrun. Private submission via Flashbots Protect / Jito bundles is the single biggest defense.

Do Telegram trading bots get frontrun?

Sometimes. Telegram bots that route swaps through public RPC and don't use private submission can be visible to searchers. Reputable ones use Jito bundles by default — see Telegram Trading Bots.

Is "frontrunning" the same as "priority gas auctions"?

Related. PGA was the Ethereum-pre-2021 mechanism searchers used to compete on gas price for the same opportunity. Today, bundle auctions (Flashbots, Jito) have largely replaced PGA-style competition.