Building a Multi-DEX Arbitrage Scanner on Arbitrum: When APIs Fail, Query the Blockchain

说明与用途

作者在 Arbitrum 上构建套利扫描器时遇到 API 限制和错误。通过直接查询 DEX 合约、验证流动性并使用正确的链特定地址和 ABI，解决了问题，获得了可靠的扫描器。

问题

Free and paid APIs for DeFi data were unreliable, misconfigured, or returned misleading prices, preventing accurate arbitrage detection on Arbitrum.

结果

By querying contracts directly and validating liquidity, the author overcame API limitations and built a reliable arbitrage scanner on Arbitrum.

工作流

• 1. Identify target DEXs (Uniswap V3, Sushiswap, Camelot).
• 2. Attempt to fetch prices via 1inch API; handle 402/timeout errors.
• 3. Switch to Alchemy RPC with ethers.js; correct chain ID and key.
• 4. Detect phantom pools by checking liquidity before price calculation.
• 5. Verify chain‑specific contract addresses (e.g., Uniswap QuoterV2).
• 6. Handle ABI differences for compatible protocols (Camelot).
• 7. Replace API calls with direct contract queries using JsonRpcProvider.
• 8. Implement liquidity checks and correct address/ABI usage.
• 9. Run scanner and alert on profitable opportunities.

证据

Free APIs have hard limits that don't care about your timeline. When they hit that limit, you're blocked.

来源

Sushiswap doesn't have real liquidity on Arbitrum. It's a ghost town.

来源