Short answer
In a custodial transfer a company holds your funds between steps, so a failure is resolved by that company. In a non-custodial transfer your funds sit in a smart contract (or are burned and re-minted) under rules anyone can read, so a failure is resolved by the contract — usually a timed refund. Non-custodial does not mean risk-free: contract bugs, verifier failures and paused protocols can still delay or put funds at risk. The useful question is who can move the money while it is in flight.
Four custody models
| Model | Who holds funds in flight | If the transfer fails | Example |
|---|---|---|---|
| Exchange (custodial) | The exchange | The exchange credits your account | Deposit, then withdraw on another network |
| Escrow + relayer (non-custodial) | A source-chain contract | Refund after the fill deadline | Across |
| Burn-and-mint | Nobody: tokens are burned, then minted | Mint can be completed after attestation | Circle CCTP |
| Key-holder bridge | Whoever holds the bridge keys | Depends on the key holders | Multisig or MPC bridges |
Exchange
When you deposit to an exchange and withdraw on another network, the exchange holds the funds in between and its terms decide what happens if something goes wrong. The upside is a support desk; the downside is account risk and policy limits. See exchange withdrawal vs bridge.
Escrow and relayer (intent bridges)
In an intent bridge you deposit into a contract on the source chain and a relayer pays you on the destination chain. Across describes the case where no relayer fills: the deposit expires, the funds remain escrowed in the origin contract, and they are refunded to the refund address after a settlement bundle and challenge period — which can take several hours (Across docs: refunds). Read how intent bridges work.
Burn-and-mint
Circle's CCTP burns USDC on the source chain and mints it on the destination chain after Circle signs an attestation, without liquidity pools (Circle: CCTP). Between burn and mint the USDC exists in neither wallet; the attestation is what lets the mint complete. Standard attestations wait for hard finality — about 15–19 minutes from Ethereum (Circle: CCTP finality).
Key-holder bridges
Some bridges release funds when a set of keys signs. If those keys are compromised or unavailable, users cannot get funds out. Our Multichain 2023 incident page describes more than $125M leaving MPC-controlled bridge addresses after the company said its CEO, the only person with access to the keys, had been detained. The Ronin 2022 incident is another key-compromise case.
What changes when a protocol pauses
Pauses protect funds but freeze transfers in flight. In the NEAR Intents incident of October 2026, swaps through the 1Click API were halted on 1 October and reopened route by route; in-flight funds were protected by the pause. Size transfers so that a one-day pause would not hurt you.
Disclosure
Until the switch to this site, the operator of upswap.io ran a swap service on this domain that executed orders through NEAR Intents (1Click). See about upswap.io and our disclosures.
How to choose
- Prefer models where you are the refund recipient and the refund rule is written in a public contract or documentation.
- Check the protocol's incident history and whether it publishes a status page.
- Keep amounts in flight proportionate to the risk; split very large transfers.
- Confirm the refund address before you sign (where refunds go).
FAQ
Is a non-custodial bridge always safer than an exchange?
Not always. It removes company custody but adds smart-contract and messaging risk. Exchanges add account and policy risk. Choose based on the amount, your access, and each option's track record.
If a bridge is hacked mid-transfer, do I get my funds back?
It depends on the incident. Some protocols cover losses, others cannot. Our incident pages record what happened to users in each case.
Does upswap.io ever hold my funds?
No. upswap.io publishes measurements only and does not execute transactions.
Sources
- Across docs: refunds — accessed 2026-10-24
- Circle developer docs: CCTP — accessed 2026-10-24
- Circle: CCTP finality and block confirmations — accessed 2026-10-24
- upswap incident pages: Multichain 2023, Ronin 2022, NEAR Intents 2026