Build MEV infrastructure on the right side of the trade.

Every second that a price discrepancy exists between two DEXes represents a profit opportunity. MEV bots exist because markets are efficient only when someone profits from inefficiency.

MEV (Maximal Extractable Value) encompasses all value that can be extracted from blockchain state by reordering, inserting or censoring transactions within a block. The beneficial forms — DEX arbitrage (keeping prices efficient across venues), liquidation bots (ensuring under-collateralised positions are closed promptly), and backrunning (capturing value after large trades) — are economically necessary functions that make DeFi work correctly. The harmful forms — sandwich attacks (exploiting user transaction visibility to front-run and back-run) — are what protocols need to defend against. PROPELOO builds both: MEV-capturing systems for traders and MEV-defence systems for protocols.

MEV system engineering.

System Layers

• Opportunity Detection Layer: Mempool monitoring, price feed, opportunity identification, profitability simulation
• Strategy Layer: Arbitrage logic, liquidation detection, backrun targeting, bundle construction
• Execution Layer: Transaction construction, gas bidding, Flashbots bundle submission, receipt monitoring
• Risk Layer: Maximum exposure limits, simulation before execution, position inventory
• Analytics Layer: Profit tracking, success rate, gas cost analysis, strategy performance

Core Technical Capabilities

• DEX Arbitrage

  Price discrepancy detection between DEX pools (Uniswap, Curve, Balancer, SushiSwap). Opportunity simulation via eth_call before execution. Atomic arbitrage via flash loans. Bundle submission via Flashbots.

• Liquidation Bots

  Monitor under-collateralised positions on Aave, Compound, MakerDAO. Liquidation opportunity simulation (profit after gas). Competitive liquidation with priority gas pricing. Flash loan-funded liquidation without upfront capital.

• Backrunning

  Large trade detection in mempool, sandwich-free backrun bundle construction, JIT (Just-In-Time) liquidity provision for large swaps.

• Flashbots Integration

  eth_sendBundle for private transaction submission, MEV-Boost integration, bundle simulation (simulate before committing), bundle merging, bid optimisation.

• Transaction Simulation

  Tenderly or local EVM fork simulation before every execution. Verify exact profit, gas cost, revert conditions. Never submit a transaction without positive simulation result.

• MEV Defence (Protocol)

  Sandwich attack analysis for protocol transactions, TWAP-based price limits, MEV-resistant AMM design, commit-reveal for fair ordering, Flashbots Protect for user transactions.

How we think about MEV.

MEV is not a bug in DeFi — it is a feature. Arbitrage bots are what keep DEX prices aligned with global market prices. Liquidation bots are what keep lending protocols solvent. The question is whether your infrastructure can capture the opportunity.

• Simulate before you execute

  Every MEV opportunity simulation should include: exact expected profit (accounting for gas costs, slippage, flash loan fees), verification that the strategy is still profitable at current block state (conditions change fast), and identification of revert conditions. A simulation that shows $0 profit means the opportunity was taken by another bot while you were calculating. A simulation that shows a loss means the opportunity was never real. Never submit without a positive simulation.

  Axiom:

• Gas bidding is the competition layer

  Multiple bots are competing for the same MEV opportunity simultaneously. The bot that wins is usually not the one with the best strategy — it is the one that bids the most gas. Gas bidding strategies: fixed premium above estimated gas (simple, not optimal), percentage of profit (never bid more than profit), adaptive (analyse historical winning bids for similar opportunities and bid just above). Flashbots bundles eliminate gas wars by having bots directly negotiate with validators.

  Axiom:

• Flash loans change the capital requirement

  Without flash loans, DEX arbitrage requires holding capital in all assets being arbitraged. Flash loans allow borrowing any amount of capital within a single transaction — as long as it is repaid with the same transaction. This means an arbitrage bot with zero capital can capture a $100K arbitrage opportunity by borrowing $100K, making the trade, and repaying the loan — all in one transaction. The only requirement is that the profit exceeds the flash loan fee (~0.09% on Aave).

  Axiom:

• MEV is competitive by nature

  The MEV space is highly competitive — the best opportunities are pursued by well-capitalized, sophisticated teams. Sustainable MEV revenue requires either a unique information advantage (faster mempool data, more frequent simulation), a better strategy (more complex multi-hop arbitrage paths that competitors miss), or a structural advantage (operator relationship with validators via MEV-Boost). Pure commodity arbitrage margins are thin.

  Axiom:

MEV system design decisions.

• Mempool monitoring approach?

  Impact: BloxRoute for latency-sensitive strategies where seeing transactions milliseconds earlier provides competitive advantage. Flashbots MEV-Share for strategies that benefit from cooperative transaction flow.

  • Public mempool (geth/erigon) — standard, visible to all competitors
  • BloxRoute private mempool — lower latency, subscription cost
  • Self-hosted full node — lowest latency to network, highest operational cost
  • Flashbots MEV-Share — cooperative MEV redistribution

• Execution via Flashbots or public mempool?

  Impact: Flashbots bundles via MEV-Boost for all meaningful MEV strategies on Ethereum — eliminates failed transaction costs, provides bundle atomicity, reduces front-running risk from the submission layer.

  • Public mempool — visible to all, gas competition
  • Flashbots bundles — private, direct to validators, no failed txs on-chain
  • MEV-Boost — enhanced Flashbots, Ethereum mainnet standard
  • Private RPC (Alchemy, Infura) — some privacy, less competitive than Flashbots

• Flash loan provider?

  Impact: Balancer for zero-fee flash loans where available. Aave for broadest token support and deepest liquidity. Strategy determines which provider is optimal for specific opportunities.

  • Aave — largest pools, 0.09% fee, most tokens
  • dYdX — some assets, lower fees historically
  • Balancer — flash loans with no fee (no fee model)
  • Uniswap v3 — flash loans for any token pair on Uniswap

• Simulation infrastructure?

  Impact: Anvil fork locally for low-latency simulation. Tenderly for debugging and strategy development. Custom revm for production bots where simulation speed is the competitive edge.

  • Tenderly API — managed, comprehensive, latency overhead
  • Local fork (Anvil/Hardhat) — fastest, self-managed
  • eth_call on production node — fast but no time travel
  • Custom EVM (revm) — maximum performance, significant engineering

• Risk management?

  Impact: Daily loss limit with automatic shutdown + per-transaction maximum gas + simulation requirement. These three controls prevent the most common failure modes: runaway gas bidding, strategy errors, and market manipulation.

  • No risk management — dangerous, single bad tx can drain capital
  • Per-opportunity exposure limit
  • Daily loss limit + circuit breaker
  • Full portfolio risk (VaR, correlation)

What PROPELOO builds.

• DEX Arbitrage Bot

  Multi-DEX arbitrage system with flash loan execution, Flashbots bundle submission, profitability simulation and competitive gas bidding.

• Liquidation Bot

  DeFi protocol liquidation keeper — position monitoring on Aave/Compound/MakerDAO, flash loan-funded liquidation, competitive execution.

• MEV Defence System

  Protect your protocol from sandwich attacks — TWAP-based price limits, MEV-resistant transaction routing, Flashbots Protect integration for users.

• JIT Liquidity Bot

  Just-In-Time liquidity provision — detect large swaps, provide concentrated liquidity to earn swap fees, remove liquidity after the swap completes.

• Cross-chain Arbitrage

  Arbitrage across chains using bridge routes — detect price discrepancies, execute cross-chain trade, account for bridge latency and fees.

• MEV Analytics

  Monitor MEV activity on your protocol — sandwich attack detection, arbitrage volume, liquidation frequency, MEV revenue distribution analytics.

The MEV engineering stack.

• Execution

  Stack: viem / ethers.js, Flashbots SDK, MEV-Boost, BloxRoute private mempool

• Simulation

  Stack: Anvil (local fork), Tenderly API, revm (Rust EVM), eth_call

• Flash Loans

  Stack: Aave Flash Loans, Balancer Flash Loans, Uniswap v3 Flash, Custom flash loan

• Data

  Stack: The Graph (pool state), Alchemy (node API), Custom mempool monitor, PostgreSQL (opportunity log)

• Language

  Stack: Go (performance), Rust (revm), Python (strategy research), TypeScript (tooling)

• Monitoring

  Stack: Profit/loss dashboard, Gas cost analysis, Success rate tracking, PagerDuty (bot failures)

MEV bot security — protecting the bot itself.

• Private key security

  MEV bot execution keys must be secured. HSM or hardware wallet for signing. Daily limits that cannot be exceeded by the bot autonomously. Immediate transfer of profits to cold storage.

• Simulation must be trusted

  A simulation that returns incorrect profit can cause the bot to execute a losing trade. Verify simulation infrastructure independently. Multiple simulation paths for high-value opportunities.

• Competitor counter-strategies

  Sophisticated competitors may monitor your bot's transaction patterns and front-run your front-running. Randomise submission timing, vary gas bidding patterns, use private mempool.

• Smart contract interaction risk

  Interacting with unknown or malicious smart contracts can drain bot funds. Only interact with audited, well-known protocols. Simulation includes checking for token approvals being abused.

• Gas cost runaway

  A bug in gas bidding logic can bid exponentially increasing gas until the bot account is drained. Maximum gas per transaction hard limit that cannot be overridden.

• Flash loan repayment guarantee

  The flash loan must be repaid within the same transaction. Any revert in the arbitrage path reverts the entire transaction including the flash loan. Simulation must verify the full profit-minus-flashloan-fee is positive.

From strategy to live MEV system.

1. 01. Strategy Design

   MEV strategy selection, opportunity analysis, profitability model, gas bidding strategy.

2. 02. Simulation Infrastructure

   Local Anvil fork, Tenderly integration, simulation pipeline.

3. 03. Opportunity Detection

   Mempool monitoring, price feed, opportunity identification logic.

4. 04. Execution Engine

   Transaction construction, flash loan integration, Flashbots bundle submission.

5. 05. Risk Controls

   Per-transaction limits, daily loss circuit breaker, simulation requirement.

6. 06. Backtesting

   Historical opportunity replay to validate strategy profitability and gas assumptions.

7. 07. Live Deployment

   Staged deployment with small capital, monitor profit/gas ratio, scale gradually.

Frequently Asked Questions