Deadline Expired Error Explainer

WHAT IT DOES

Deadline Expired Error Explainer takes a pending or recent transaction hash and determines whether it will fail due to an expired deadline parameter. Many DeFi transactions—such as swaps, liquidity operations, permit approvals, and liquidations—include a deadline to protect users from unfavorable price changes or stale signatures. This tool decodes the transaction calldata to identify the deadline parameter (commonly named "deadline," "timestamp," "expiry," or similar), reads the current block timestamp from the latest block, and compares the two. It then reports whether the deadline has already passed, how much time remains (or has elapsed), and what the user needs to do to fix the issue—such as increasing the deadline or resubmitting with a later timestamp. The tool also fetches historical block timestamps to detect chain congestion or slowdown, and checks for pending transactions from the same sender to identify nonce-related delays that might cause the transaction to be mined after the deadline even if it appears valid at check time.

HOW TO USE

Paste any transaction hash (pending or already mined) into the input field, select the network, and click "Check deadline". 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 deadline parameter by scanning for common parameter names and analyzing the last uint256 argument (a common pattern in many DeFi contracts). The current block timestamp is fetched, and the tool computes whether the deadline has expired. The AI layer then generates a plain‑English summary: whether the transaction will revert due to an expired deadline, the deadline value, the current time, and how much time remains or has passed. You can click on the transaction hash or addresses to view them on the block explorer for additional context.

SMART DEADLINE DETECTION WITH CONTEXT-AWARE PARSING

Unlike simple timestamp checkers that require manual input of the deadline value, this tool automatically extracts the deadline from the transaction's calldata using a multi‑strategy approach. It first attempts to decode the calldata against a library of common function signatures from popular DeFi protocols (Uniswap, PancakeSwap, SushiSwap, Balancer, etc.) to precisely identify the deadline parameter by name. If that fails, it uses a heuristic scan of the calldata to find the last uint256 argument, which is often the deadline in many contracts. It also checks for parameter names containing "deadline", "timestamp", "expiry", "timeout", "cutoff", or "valid" to increase detection accuracy. Once the deadline is found, the tool compares it against the current block timestamp and—critically—also checks the timestamp of the previous 10 blocks to estimate chain congestion. This helps distinguish between a genuinely expired deadline and a transaction that might still be mined if the chain is producing blocks slowly. If the deadline is set as a block number rather than a timestamp (some contracts use this pattern), the tool detects that format and compares against the current block number instead.

WHAT IT CANNOT SEE

This tool cannot detect deadlines that depend on off‑chain state (e.g., a deadline based on a price feed update that hasn't occurred yet, or a deadline that is validated against an off‑chain signature that hasn't been submitted). It cannot predict future block timestamps or chain congestion that might cause the transaction to be mined after the deadline even if it appears valid at check time—the check reflects the current block, not the future. It cannot verify that the sender intended to use the exact deadline value being checked—the tool reads what is on‑chain, not the user's intent. It cannot detect deadlines in contracts that use non‑standard validation patterns (e.g., deadlines encoded in storage rather than calldata, or deadlines that are compared against a custom timestamp source that is not the block timestamp). It cannot guarantee that a retry with an adjusted deadline will succeed even if the current deadline appears valid, due to race conditions, front‑running, or state changes between the check and the transaction being mined. It cannot detect if the deadline is intentionally set too short as a security measure—this tool only checks whether the deadline has expired based on the current block timestamp, it does not assess intent or risk.

PLEASE NOTE

This tool works only for EVM‑compatible chains (Ethereum, Polygon, BSC, Arbitrum, Optimism, Avalanche C‑chain, etc.). It relies on standard transaction calldata decoding and may not detect deadline parameters in highly custom or obfuscated contracts. All explanations are AI‑generated from data the app reads on‑chain—the AI synthesizes the deadline value, current block time, and transaction 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 deadline explanation does not replace your own verification of the transaction details, including the deadline value and the contract you are interacting with. This tool is provided free of charge, with no warranty of accuracy or completeness.