If you move tokens between chains, a relay bridge uses relayers to carry your transfer record to the receiving chain. In a relay bridge transfer, relayers are computers that pass that record between blockchains. The receiving chain checks it before releasing tokens, while fees and wait times depend on the route and its security rules.
A Bridge Connects Separate Blockchains
A crypto relay bridge connects blockchains that cannot read each other’s transactions directly. It can pass a message, or small instruction, along with the information needed to transfer a token.
Your balance does not travel between chains. A contract, which is a program on the source chain, holds or destroys the tokens you send. A linked contract on the destination chain releases existing tokens or creates a matching version.
That matching version may be a wrapped token: a claim tied to tokens held elsewhere. Its name can look familiar while its contract address differs. If you need a specific token on Base, check the destination token address before sending.
A Transfer Has Four Stages
A relay bridge moves tokens through four stages: send, confirm, verify, and deliver. You select the source chain, destination chain, token, amount, and receiving wallet. The quote should show which token will arrive and how much you can expect.
If the token needs approval, first allow the bridge contract to use the amount you chose. Approval is a separate transaction and uses gas, the chain’s processing fee. Then you sign the transfer, which holds or destroys your tokens and records a message.
Relayer nodes watch for that message. After enough source-chain confirmations, they carry it and any required evidence to the destination contract. Confirmations are new blocks added after your transaction, making a reversal less likely.
Message verification is the rule for deciding whether the record is genuine. The destination contract may check evidence from the source chain, several signatures, or a verifier’s report. Once the check passes, it releases or creates the output token.
Some fast routes use a different delivery step. A relayer pays you from its own tokens on the destination chain, then gets repaid later. This depends on liquidity, meaning tokens ready to pay recipients on that chain.
The Quote Shows the Full Transfer Cost
The quote combines source gas, destination processing, and any relayer or liquidity charge. Relay bridge fees and speed change with network traffic and the funds available on the route. Some routes deduct charges from the amount sent; others ask for a separate payment.
The source transaction uses that chain’s native coin for gas. An approval, when needed, adds another source transaction. Before signing, check both the wallet’s gas estimate and the quote’s amount received.
Say you send 1,000 dollar-denominated tokens from Ethereum to Base. If the quote deducts $1 for delivery and 0.05% for liquidity, you receive 998.50 tokens. If source gas costs around $3, you also spend that amount in Ethereum’s native coin.
Compare the amount received with the total you spend. A fixed $1 charge takes 1% of a $100 transfer but 0.1% of a $1,000 transfer. Quotes can change, so read the fresh amount before each transfer.
Confirmations and Delivery Set the Wait Time
A transfer can arrive in seconds on some fast routes, or take 15–30 minutes when it waits for source-chain finality. Finality means the source transaction is settled enough that it should not be reversed. Network traffic, relayer queues, and destination processing can add time.
Ethereum finality alone is often around 15 minutes. A route waiting for it cannot finish in two minutes. A fast fill pays the recipient earlier because the relayer takes the risk of waiting; it does not make Ethereum settle faster.
Once your source transaction succeeds, watch the transfer status and destination transaction. A confirmed source transaction does not mean delivery is complete. If it stalls, keep the source transaction hash and check the route’s retry or refund steps before sending again.
Check the Route and Output Token Before Sending
A relay bridge is only as safe as its message verification and the token it delivers. Check who can approve a cross-chain message, how many independent parties must agree, and who can change the contracts. A single key or small signer group requires more trust in its operators.
Check the exact networks, receiving address, output token address, minimum amount received, and any transfer limits. For an unfamiliar route or token, send a small test first. Keep enough native coin for source gas and for any action you plan to take after arrival.
After delivery, check your balance on the destination chain. If the token is missing from your wallet, look up the destination transaction and token address before assuming the transfer failed. Some wallets simply hide an unfamiliar wrapped token.