Across Review
Optimistic security explained in one sentence
of 10
Across states its security assumption plainly: bundles are proposed with a bond and accepted unless challenged, and only a single honest actor is needed to dispute an invalid proposal. It supports 28 chains and is audited by OpenZeppelin, under a BUSL licence until 2027.
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Licence
BUSL-1.1, change date 27 Jul 2027 to GPL-3.0-or-later
Trust model
Optimistic verification with bonded proposals and a challenge window
Security assumption
A single honest actor suffices to dispute
Chains
28
Auditors
OpenZeppelin, plus UMA audits
Scores
Each criterion carries equal weight. The overall score is the average of these 5 scores — (6.0 + 10.0 + 4.0 + 9.0 + 8.0) ÷ 5 = 7.4.
Pros
- Trust model stated in one clear sentence: only a single honest actor need dispute an invalid proposal
- Uses the UMA Optimistic Oracle, an external and independently documented component
- 28 chains stated with roughly two-second fills
- All audits by OpenZeppelin, covering V2, V3 and the token distributor
- Integrator app fee documented with its range, 0 to 1
Cons
- Business Source License 1.1 until 27 July 2027 — not an open-source licence today
- No fixed fee percentage: cost is the difference between input and output amount
- LP and relayer fee components are described but not quantified
The clearest statement of a security assumption here
Across states that bundles are proposed with a bond and accepted unless challenged within a window, and that only a single honest actor needs to dispute an invalid proposal. That sentence tells a reader exactly what they are relying on — and what would have to fail for funds to be at risk — in a way that a claim of being trustless never does.
Cost is a difference, not a rate
The documentation defines total fee as input amount minus output amount, split conceptually into an LP fee compensating capital utilisation and a relayer fee covering gas, opportunity cost and risk. Neither is published as a percentage, so the price is only knowable at quote time. Integrators may add an app fee, documented as a decimal from 0 to 1.
Licence
Business Source License 1.1, licensed by Risk Labs, converting to GPL v3.0 or later no later than 27 July 2027.
How it compares
Synapse
MIT-licensed, and little else readable
Chainflip
Apache-licensed, with documentation gaps
Squid
Charges nothing, documents little
deBridge
Per-chain flat fees, published in full
Hop Protocol
Every fee component published as a range
Stargate / LayerZero
Exact fee split, and a licence that expired unresolved
Celer cBridge
GPL-3.0 with a published fee ceiling
Wormhole
A named quorum: 13 of 19 guardians
Axelar
Apache-licensed with the deepest audit archive
Sources
Scored from published primary sources rather than hands-on use. Every figure above comes from one of the pages below, on the date shown. Manufacturers change prices and specifications without notice — if something here no longer matches the source, tell us and we will correct it.
- 1.Across — fees documentation — checked
- 2.Across — intents architecture and optimistic verification — checked
- 3.Across contracts — LICENSE — checked
- 4.Across — audits — checked
Frequently asked questions
How does Across secure transfers?
Through optimistic verification: bundles are proposed with a bond and accepted unless challenged within a window, using the UMA Optimistic Oracle. Across states only a single honest actor is needed to dispute an invalid proposal.
What does Across charge?
No fixed percentage. The total fee is the input amount minus the output amount, comprising an LP fee and a relayer fee; integrators may add their own app fee.
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