What happens if the swap timer expires before both sides confirm

05 September 2026

If the swap timer expires before both sides confirm, the incomplete swap is cancelled and each party's funds are returned to their original wallets. No funds are lost, but the process must be restarted from scratch.

The timer exists because cross-chain swaps are inherently asynchronous. When you swap crypto across chains without a bridge or centralised account, neither party can control both chains simultaneously. The timer protects both sides from indefinite lockup.

How the timer works

A swap begins when one party locks their coins into a smart contract on their chain. That contract contains a time lock - a future block height or timestamp after which the locked coins can be reclaimed by the depositor. The other party then has until that deadline to lock their corresponding coins on the other chain.

The timer is set by the party who initiates the swap. Typical durations range from a few hours to a day, depending on the chains involved. Faster chains like Solana or BSC use shorter timers; slower chains like Bitcoin or Ethereum use longer ones.

What actually happens

Scenario A: Party A locks coins. Party B never locks. After the timer expires, Party A calls a refund function on the contract and reclaims their coins. The swap is dead.

Scenario B: Party A locks coins. Party B locks coins, but Party A fails to complete the second step (claiming B's coins on the other chain). After the timer expires, Party B can reclaim their coins from their own chain's contract. Party A's original coins remain locked - but Party A can also now reclaim them, because the time lock has expired for both sides.

Scenario C: Both parties lock coins, but neither claims the other's locked coins before the timer expires. Both can reclaim their own deposits. No coins move.

In every case, the worst outcome is a delay. The locked coins are never burned or sent to an inaccessible address. The smart contract is designed to release them back to the original owner after the timeout.

Why this is necessary

Without a timer, a dishonest party could lock coins and then refuse to complete the swap, leaving the other party's funds stuck indefinitely. The timer creates a firm deadline. After that deadline, the locked funds are no longer hostage to the other party's cooperation.

The timer also prevents a subtler attack: a party could lock coins, wait for the other party to lock, then deliberately delay claiming while watching the market. If the price moves in their favour, they claim; if not, they let the timer expire and walk away. The timer limits how long they can hold the other party's funds while they decide.

What you should do

If the timer expires, do not panic. Your coins are still yours. You will need to initiate a refund transaction, which usually costs a small network fee. After that, you can start a new swap.

Before starting a new swap, consider why the previous one failed. Common reasons: the other party went offline, the network was congested, or the timer was set too short for the chain's confirmation speed. Adjust the timer length accordingly.

If you are the party who locked first, you are the only one who can trigger the refund. The contract does not automatically return your coins - you must send a transaction to call the refund function. Some swap interfaces do this for you automatically after expiry, but not all. Check the interface.

For a fuller picture of how these swaps work without a central custodian, read the hub page "Swapping crypto across chains". It explains the overall mechanism that makes these timers meaningful.

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