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Bridge review

Across review

Intent bridge — relayers pay you first, then are repaid through optimistic settlement secured by UMA

Snapshot Cartoon avatar of Arnold BurnBy Updated Data gate passed · 36 routes / 7 d

Key findings

Across Protocol is an intent-based bridge: you deposit into a SpokePool, a relayer pays you on the destination chain from its own capital, and the relayer is repaid later through bundles that can be disputed for 30 minutes and escalated to UMA. Its admin multisig can upgrade SpokePools without delay. Its first reported attack since 2021 (Solana, July 2026) cost the relayer, not users.

As of 3 Nov 2026, 10:35 UTC (run #538), Across returned quotes on 36 sampled routes (192 quote rows in this packet). At $200 it was the cheapest ranked quote on 8 routes. Median cost among its non-negative $200 quotes: 5.38 bps (cheapest observed 0.98 bps). Sources reporting it: Across, LI.FI. Real-money tests: none yet — planned after launch.

Source: upswap.io snapshot #538 · CC BY 4.0 · Zenodo DOI: Example / pending

How does Across work?

You deposit into the origin chain's SpokePool contract and specify recipient, destination chain, output token and a fill deadline. A relayer watches for the deposit and pays you on the destination chain from its own funds; your deposit stays in the SpokePool. Periodically a whitelisted proposer posts a root bundle to the HubPool on Ethereum stating what each relayer is owed. The proposer bonds 0.45 ABT and the bundle can be challenged for 30 minutes; disputes go to UMA's optimistic oracle (L2Beat).

Liquidity providers deposit single tokens into the HubPool and earn the LP fee. On chains with a canonical L1↔L2 messenger, Across rebalances through that bridge; on others it uses storage-proof adapters, LayerZero OFT, or Circle CCTP for USDC (L2Beat). A newer "V5 Gateway" lets solvers execute user-signed multi-step paths using standing token approvals.

Scorecard (no total score)

Cost excl. gas

5.38
median bps · n=64

Coverage

36
routes this packet

$200 wins

8
cheapest finishes

Quote rows

192
all tiers

Real transfers

0
not enough data

Upgrade / custody

—
待核实

How much does Across cost on each route?

336 runs · 7 d

Over the last 7 days Across's median $200 cost ranged from 0.98 bps (Ethereum → OP Mainnet ETH) to 5.69 bps (Base → Ethereum ETH); it was the cheapest bridge in 4239 route-runs.

Across: $200 cost distribution by route (7 days)Per route: whisker = min to max, box = 25th to 75th percentile, thick tick = median of this bridge's cheapest rankable $200 quote per run, 336 runs. Amber rows: this bridge was cheapest on the route at least once. Log scale, bps, excl. gas.0.20.51251020501002005001,0002,000bpsEthereum → OP Mainnet ETH0.98Solana → Base USDC1Ethereum → Solana USDC1Solana → Ethereum USDC1Solana → Arbitrum One USDC1Ethereum → OP Mainnet USDC1Base → OP Mainnet USDC1Ethereum → Base ETH1.2Ethereum → Base USDC1.2Arbitrum One → Base USDC1.2OP Mainnet → Base USDC1.2Polygon PoS → Base USDC1.2Arbitrum One → BNB Chain USDT1.2Ethereum → BNB Chain USDT1.2Ethereum → Avalanche C-Chain USDC1.2Arbitrum One → Hyperliquid (HyperCo…1.2Base → Solana USDC1.3Base → Polygon PoS USDC1.4Arbitrum One → Solana USDC1.4Ethereum → Arbitrum One USDC1.4Polygon PoS → Arbitrum One USDC1.4Arbitrum One → Polygon PoS USDC1.4Base → Arbitrum One USDC1.4Ethereum → Arbitrum One USDT1.4Ethereum → Polygon PoS USDC1.4BNB Chain → Arbitrum One USDT1.4Ethereum → Arbitrum One ETH1.5Arbitrum One → Ethereum USDC2.1Base → Ethereum USDC2.1Arbitrum One → OP Mainnet ETH4.9Arbitrum One → Base ETH5.1OP Mainnet → Base ETH5.1Base → Arbitrum One ETH5.4OP Mainnet → Arbitrum One ETH5.4Arbitrum One → Ethereum ETH5.7Base → Ethereum ETH5.7
Across: $200 cost distribution by route (7 days)Per route: whisker = min to max, box = 25th to 75th percentile, thick tick = median of this bridge's cheapest rankable $200 quote per run, 336 runs. Amber rows: this bridge was cheapest on the route at least once. Log scale, bps, excl. gas.0.20.51251020501002005001,0002,000bpsEthereum → OP Mainnet ETH0.98Solana → Base USDC1Ethereum → Solana USDC1Solana → Ethereum USDC1Solana → Arbitrum One USDC1Ethereum → OP Mainnet USDC1Base → OP Mainnet USDC1Ethereum → Base ETH1.2Ethereum → Base USDC1.2Arbitrum One → Base USDC1.2OP Mainnet → Base USDC1.2Polygon PoS → Base USDC1.2Arbitrum One → BNB Chain U…1.2Ethereum → BNB Chain USDT1.2Ethereum → Avalanche C-Cha…1.2Arbitrum One → Hyperliquid…1.2Base → Solana USDC1.3Base → Polygon PoS USDC1.4Arbitrum One → Solana USDC1.4Ethereum → Arbitrum One US…1.4Polygon PoS → Arbitrum One…1.4Arbitrum One → Polygon PoS…1.4Base → Arbitrum One USDC1.4Ethereum → Arbitrum One US…1.4Ethereum → Polygon PoS USDC1.4BNB Chain → Arbitrum One U…1.4Ethereum → Arbitrum One ETH1.5Arbitrum One → Ethereum US…2.1Base → Ethereum USDC2.1Arbitrum One → OP Mainnet…4.9Arbitrum One → Base ETH5.1OP Mainnet → Base ETH5.1Base → Arbitrum One ETH5.4OP Mainnet → Arbitrum One…5.4Arbitrum One → Ethereum ETH5.7Base → Ethereum ETH5.7
Across: $200 cost distribution by route (7 days)Per route: whisker = min to max, box = 25th to 75th percentile, thick tick = median of this bridge's cheapest rankable $200 quote per run, 336 runs. Amber rows: this bridge was cheapest on the route at least once. Log scale, bps, excl. gas.0.20.51251020501002005001,0002,000bpsEthereum → OP…0.98Solana → Base1Ethereum → Sol…1Solana → Ether…1Solana → Arbit…1Ethereum → OP…1Base → OP Main…1Ethereum → Base1.2Ethereum → Base1.2Arbitrum One →…1.2OP Mainnet → B…1.2Polygon PoS →…1.2Arbitrum One →…1.2Ethereum → BNB…1.2Ethereum → Ava…1.2Arbitrum One →…1.2Base → Solana1.3Base → Polygon…1.4Arbitrum One →…1.4Ethereum → Arb…1.4Polygon PoS →…1.4Arbitrum One →…1.4Base → Arbitru…1.4Ethereum → Arb…1.4Ethereum → Pol…1.4BNB Chain → Ar…1.4Ethereum → Arb…1.5Arbitrum One →…2.1Base → Ethereum2.1Arbitrum One →…4.9Arbitrum One →…5.1OP Mainnet → B…5.1Base → Arbitru…5.4OP Mainnet → A…5.4Arbitrum One →…5.7Base → Ethereum5.7
Per route: whisker = min to max, box = 25th to 75th percentile, thick tick = median of this bridge's cheapest rankable $200 quote per run, 336 runs. Amber rows: this bridge was cheapest on the route at least once. Log scale, bps, excl. gas.
Across: $200 cost distribution by route (7 days)
RoutenMinP25MedianP75MaxCheapest runs
Ethereum → OP Mainnet ETH3360.980.980.980.981.33194
Solana → Base USDC3361.001.001.001.001.00318
Ethereum → Solana USDC3361.001.001.001.001.00334
Solana → Ethereum USDC3361.001.001.001.001.00336
Solana → Arbitrum One USDC3361.001.001.001.001.00237
Ethereum → OP Mainnet USDC3361.011.011.011.011.360
Base → OP Mainnet USDC3361.011.011.011.011.380
Ethereum → Base ETH3361.171.171.181.182.15238
Ethereum → Base USDC3361.191.191.201.202.070
Arbitrum One → Base USDC3361.191.191.201.202.070
OP Mainnet → Base USDC3361.191.191.201.201.980
Polygon PoS → Base USDC3361.191.191.201.201.970
Arbitrum One → BNB Chain USDT2970.201.201.211.221.22297
Ethereum → BNB Chain USDT2970.201.201.211.221.22297
Ethereum → Avalanche C-Chain USDC3361.201.201.211.211.521
Arbitrum One → Hyperliquid (HyperCore) USDC3361.151.201.231.2957.410
Base → Solana USDC3361.301.301.301.301.30300
Base → Polygon PoS USDC3361.021.371.401.421.690
Arbitrum One → Solana USDC3361.401.401.401.401.40316
Ethereum → Arbitrum One USDC3361.391.401.401.4266.80152
Polygon PoS → Arbitrum One USDC3361.391.401.401.4266.50196
Arbitrum One → Polygon PoS USDC3361.021.381.411.451.670
Base → Arbitrum One USDC3361.391.401.411.4266.5585
Ethereum → Arbitrum One USDT3361.391.401.411.4245.67180
Ethereum → Polygon PoS USDC3361.021.381.411.451.670
BNB Chain → Arbitrum One USDT3001.401.421.436.4245.58159
Ethereum → Arbitrum One ETH3361.441.461.471.4862.80196
Arbitrum One → Ethereum USDC3361.491.722.154.041,911.88133
Base → Ethereum USDC3361.491.722.153.991,911.88131
Arbitrum One → OP Mainnet ETH3362.582.604.874.894.927
Arbitrum One → Base ETH3362.782.805.075.095.116
OP Mainnet → Base ETH3362.782.805.075.095.116
Base → Arbitrum One ETH3363.083.105.365.3864.592
OP Mainnet → Arbitrum One ETH3363.083.105.365.3864.342
Arbitrum One → Ethereum ETH3313.275.385.697.051,553.47105
Base → Ethereum ETH3313.275.375.697.091,563.8611

Where does Across win at $200?

Across best $200 quote by route
RouteVia sourcebpsRoute leader
Solana → Base USDCAcross1.00this bridge
Ethereum → Solana USDCAcross1.00this bridge
Solana → Ethereum USDCAcross1.00this bridge
Ethereum → Base ETHAcross1.17this bridge
Arbitrum One → BNB Chain USDTAcross1.20this bridge
Ethereum → BNB Chain USDTAcross1.20this bridge
Base → Solana USDCAcross1.30this bridge
Arbitrum One → Solana USDCAcross1.40this bridge
Ethereum → OP Mainnet ETHAcross0.98Layerswap 0.35
Solana → Arbitrum One USDCAcross1.00Layerswap 0.60
Base → OP Mainnet USDCAcross1.01Eco 0.00
Ethereum → OP Mainnet USDCAcross1.01Eco 0.00
Ethereum → Base USDCAcross1.19Eco 0.00
Arbitrum One → Base USDCAcross1.19Eco 0.00
OP Mainnet → Base USDCAcross1.19Eco 0.00
Polygon PoS → Base USDCAcross1.19Eco 0.00
Ethereum → Avalanche C-Chain USDCAcross1.20NEAR Intents 1Click 0.31
Arbitrum One → Hyperliquid (HyperCore) USDCAcross1.27Hyperliquid Native 0.00
Base → Polygon PoS USDCAcross1.37Eco 0.00
Base → Arbitrum One USDCAcross1.40Eco 0.00
Ethereum → Arbitrum One USDCAcross1.40Eco 0.00
Polygon PoS → Arbitrum One USDCAcross1.40Eco 0.00
Ethereum → Arbitrum One USDTAcross1.41Eco 0.87
BNB Chain → Arbitrum One USDTAcross1.42Celer 1.36
Ethereum → Polygon PoS USDCAcross1.43Eco 0.00
Arbitrum One → Polygon PoS USDCAcross1.44Eco 0.00
Ethereum → Arbitrum One ETHAcross1.47Layerswap 0.16
Base → Ethereum USDCAcross2.10Eco 0.00
Arbitrum One → Ethereum USDCAcross2.14Eco 0.00
Arbitrum One → OP Mainnet ETHAcross4.89Celer 1.92
Arbitrum One → Base ETHAcross5.09Celer 1.50
OP Mainnet → Base ETHAcross5.09Celer 1.50
OP Mainnet → Arbitrum One ETHAcross5.38Layerswap 0.40
Base → Arbitrum One ETHAcross5.38Layerswap 0.45
Arbitrum One → Ethereum ETHAcross6.12Eco 2.39
Base → Ethereum ETHAcross6.12Relay 3.72

What are the risks of using Across?

sources checked 2026-10-24

Each item links to its source (L2Beat, DefiLlama or official docs). Items we could not verify are marked 待核实. No overall score.

  • Settlement & disputes

    Relayer repayments are optimistic: a bonded proposer posts bundles, anyone can dispute within 30 minutes by posting an equal bond, and disputes are resolved by UMA token voting. Users are paid before settlement, so a settlement failure hits relayers and LPs first.

    L2Beat

  • Upgrade authority

    The Across Multisig (3/5) can upgrade the SpokePools with no delay; a separate path through the OptimisticGovernor applies a 2-day delay. The V5 Gateway is upgradable with no delay by a 3/5 Across Gateway Multisig, which puts standing approvals to the Gateway at risk if that multisig is compromised.

    L2Beat

  • Approval risk

    Classic deposits need an approval only for the amount you bridge. V5 Gateway executions pull funds via standing approvals or signed permits, so prefer exact-amount approvals.

    L2Beat

  • Recent changes

    L2Beat lists high-severity updates on 2026-10-16, 2026-10-12, 2026-09-15, 2026-08-25 and 2026-08-17 (the V5 Gateway launch). The last SpokePool upgrade on Ethereum was on 2026-08-14.

    L2Beat

  • Security incidents

    17 July 2026: forged Solana deposit events fooled the Risk Labs relayer; ≈ $4.5M gross relayer loss, no user funds lost; Solana routes paused about 12 hours. The attacker later returned the remaining ≈ $3.7M for a 10% bounty.

    The CryptonomistDefiLlama HacksAcross Protocol

What fees does Across charge?

LP fee
Utilisation-based (Aave-style two-slope curve); zero when the relayer is repaid on the origin chain. Across
Relayer fee
Covers the relayer's destination gas, capital cost and risk; the total fee is simply input minus output. Across

On upswap, Across source-chain gas is never counted in rankings (decided policy). Our API calls carry integrator ID 0x03db with an app fee of 0.

How did its quotes perform in our data?

run #538

Quotes for Across in run #538, by the API that reported them.

Quote performance by source
SourceTypeRoutesQuote rows$200 cheapestMedian $200 bpsNegative-cost rows
Acrossdirect3610881.400
LI.FIvia aggregator2884026.420

Negative-cost quotes (receiving more than you send) are listed, never ranked. Cost excludes source-chain gas.

Has upswap tested it with real money?

Not yet. Real-money tests are planned after launch; no test wallets or transactions are published yet.

What are the pros and cons?

Pros

  • Users are paid by relayers in seconds and never wait for settlement.
  • A settlement failure is absorbed by relayers and LPs first — the July 2026 incident showed this in practice.
  • Contracts and permissions are documented in detail on L2Beat.

Cons

  • A 3/5 multisig can upgrade SpokePools and the V5 Gateway with no delay.
  • Coverage is focused on popular chains and assets.
  • Relay of messages to some chains depends on third-party bridges (LayerZero OFT, CCTP).

Who is Across for?

Good for fast ETH and stablecoin transfers between major Ethereum L2s and L1 where you value speed and a clear settlement design; for large amounts, check the upgrade-without-delay risk and split transfers.

Has it been hacked?

Incident library →

Which official links are verified?

  • App across.to · checked 2026-10-24
  • Docs docs.across.to · checked 2026-10-24
  • Fee docs docs.across.to/introduction/fees · checked 2026-10-24

Sources

  1. Across — interop protocol page — L2Beat · Database · checked
  2. Fees in the System — Across · Docs · checked
  3. Across — protocol page — DefiLlama · Database · checked
  4. DefiLlama Hacks — Across 2026-07-17 — DefiLlama Hacks · Database · checked
  5. Across Solana Relayer Attack Drained $4.5M — No User Lost a Cent — The Cryptonomist · Media · checked
  6. Update on the July 17 Relayer Incident: the funds are back — Across Protocol · Official · checked

Changelog

  • — Draft review written: mechanism, risk card and fees from L2Beat and Across docs; incident linked.

How do I cite this page?

Burn, A. / upswap.io (2026). Across Protocol review. Updated 2026-10-24. https://upswap.io/bridges/across#summary. CC BY 4.0. Accessed ____.

Stable anchors: #summary #type #risk #fee-structure #performance #tests #pros-cons #fit #incidents #official #sources #changelog #disclosure #cite