Slippage Exceeded Error Explainer

WHAT IT DOES

Slippage Exceeded Error Explainer takes a pending or recent swap transaction hash and determines whether it will fail due to exceeded slippage tolerance. It decodes the transaction calldata to extract swap parameters—including the amount of tokens being sent (amountIn), the minimum amount the user expects to receive (amountOutMin), and the token path (the input and output token addresses). It then reads the current reserves of the liquidity pool for that token pair directly from the router contract at the current block. Using the constant product formula (x * y = k) with a 0.3% fee applied, it calculates the expected output amount if the swap were executed right now. The tool compares this expected output against the user's minimum accepted output. If the expected output is less than the minimum, the swap would revert due to slippage. The output includes the current reserves, the calculated expected output, the user's minimum, the shortfall (if any), and a plain‑language explanation of the market conditions that caused the price movement.

HOW TO USE

Paste any swap transaction hash (pending or already mined) into the input field, select the network, and click "Check slippage". The tool connects to your wallet via the EVM bridge (read‑only; it never signs or sends anything) to fetch the transaction details and decode the calldata. It automatically detects the swap function, extracts amountIn and amountOutMin, and identifies the token path. It then reads the pool reserves from the router contract (the same contract the transaction is calling) and calculates the expected output at current reserves. The AI layer generates a plain‑English summary: whether the swap will fail due to slippage, the expected vs. minimum output, the shortfall, and what the user can do to fix it (e.g., increase slippage tolerance or wait for price stability). You can click on the transaction hash to view it on the block explorer.

PARALLEL RESERVE FETCH WITH CONSTANT PRODUCT CALCULATION

Unlike simple price checkers that only show the current price, this tool performs a multi‑step calculation that mirrors the actual AMM math used by Uniswap V2 and compatible routers. It first fetches the transaction details and decodes the swap function using a library of common signatures (swapExactTokensForTokens, swapExactETHForTokens, swapTokensForExactETH, etc.). In parallel, it reads the current reserves from the router's getReserves() function and the token addresses from token0()/token1(). It then applies the constant product formula with the standard 0.3% fee: amountOut = (amountIn * 0.997 * reserveOut) / (reserveIn + amountIn * 0.997). This calculation is performed using ethers BigNumber to avoid precision loss. The tool also checks historical reserves from the previous 10 blocks by using eth_call with blockNumber overrides—if the price has moved significantly in the last few blocks, it flags this as high volatility and warns the user. If any RPC call fails, it falls back to the next endpoint without stopping the scan.

WHAT IT CANNOT SEE

This tool cannot detect slippage that depends on off‑chain state (e.g., price feeds that update off‑chain, or cross‑chain price discrepancies). It cannot predict future price changes from other pending transactions that may execute before this one, potentially widening slippage beyond the check. It cannot verify that the sender intended to use the exact slippage parameters being checked—the tool reads what is on‑chain, not the user's intent. It cannot detect slippage in contracts that use non‑standard price calculation patterns (e.g., oracle‑based pricing, custom AMM math, or pricing that depends on storage rather than simple reserve ratios). It cannot guarantee that a retry with adjusted slippage will succeed even if the current slippage appears acceptable, due to race conditions, front‑running, or state changes between the check and the transaction being mined. It cannot detect if the slippage tolerance is intentionally set too low as a security measure—this tool only checks whether the transaction would exceed the stated tolerance based on current reserves, it does not assess intent or risk. It also cannot detect slippage in V3‑style concentrated liquidity pools or stable‑swap pools, which use different math.

PLEASE NOTE

This tool works only for EVM‑compatible chains (Ethereum, Polygon, BSC, Arbitrum, Optimism, Avalanche C‑chain, etc.) and supports standard Uniswap V2‑style routers. It does not support Uniswap V3 or custom AMMs with different fee structures. All explanations are AI‑generated from data the app reads on‑chain—the AI synthesizes the reserve data, swap parameters, and market context into plain English, but it does not have special access to private contract logic or off‑chain data. Always review what you are actually signing in your wallet before approving any transaction; a slippage explanation does not replace your own verification of the transaction details, including the amountOutMin and the contract you are interacting with. This tool is provided free of charge, with no warranty of accuracy or completeness.