Across allows users to send tokens from one chain to another almost immediately without having to wait for the rollup’s challenge period. Liquidity providers provide liquidity and relayers handle the fills and in return they charge a transfer fee (supply-side fees).

Across is a cross-chain token bridge for L2s and rollups. Across was founded by Hart Lambur and launched in 2021.

ACX tokenholders own and govern the protocol. They currently don’t take a cut of the total transfer fees paid by the users (revenue). Across’ investors include Hack VC, Placeholder and Blockchain Capital.

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Across

# Across Supply-side fees Methodology

## 1. Overview

Across fees supply side represents the total fees earned by liquidity providers and relayers in the Across protocol across all supported chains and protocol versions. This metric captures the revenue generated by the supply side participants (LPs and relayers) who facilitate cross-chain bridging by providing liquidity and relay services. The calculation combines explicit fee amounts from earlier protocol versions with fee calculations derived from input/output amount differences in newer versions, covering the protocol's evolution from v1 through v3.

## 2. Data sources

- **Ethereum deposit relay events**: `DepositRelayed` events from Across v1 BridgePoolProd contracts containing LP and relayer fee percentages
- **Multi-chain filled relay events**: `FilledRelay` events from Across v2 spoke pool contracts across Ethereum, Polygon, Arbitrum, Optimism, Base, and zkSync Era containing fee percentages and fill amounts
- **Extended chain relay events**: `FilledRelay` events from Across v2.5 spoke pool contracts across 10 chains including BSC, Linea, Scroll, and Worldchain with updated relay execution data
- **V3 relay events**: `FilledV3Relay` events from Across v3 contracts emitted through v2.5 proxy contracts with input/output amount data
- **Token routing data**: `SetPoolRebalanceRoute` events from Ethereum HubPool contracts mapping chain-specific token addresses to L1 equivalents
- **End-of-day price feeds**: Token price data for USD conversion
- **Token metadata**: Decimal places and symbol information for amount normalization

## 3. Step-by-step calculation

### Component A: V1 bridge fees
- **Purpose**: Calculate fees from Across v1 deposits where fees are explicitly defined as percentages
- **Logic**: Extract `DepositRelayed` events from Ethereum BridgePoolProd contracts and match with trading pool metadata to identify token addresses. Extract LP fee percentage (`realizedLpFeePct`), slow relayer fee percentage (`slowRelayFeePct`), and instant relayer fee percentage (`instantRelayFeePct`) from event data. Calculate LP fee amount by multiplying LP fee percentage by transfer `amount`. Calculate total relayer fee amount by multiplying sum of slow and instant relayer fee percentages by transfer `amount`. Sum LP and relayer fees to get total fees per transaction.
- **Key fields**: `realizedLpFeePct` (LP fee percentage), `slowRelayFeePct` and `instantRelayFeePct` (relayer fee percentages), `amount` (transfer amount), `address` (pool contract address)

### Component B: V2 bridge fees
- **Purpose**: Calculate fees from Across v2 filled relays using explicit fee percentages and fill amounts
- **Logic**: Process `FilledRelay` events from spoke pool contracts across multiple chains including Ethereum, Polygon, Arbitrum, Optimism, Base, and zkSync Era. Extract LP fee percentage (`realizedLpFeePct`) and relayer fee percentage (varies by contract version - either `appliedRelayerFeePct` or `updatableRelayData.relayerFeePct`) from event data. Calculate LP fee amount by multiplying LP fee percentage by fill `amount`. Calculate relayer fee amount by multiplying relayer fee percentage by fill `amount`. Sum LP and relayer fees to get total fees per filled relay.
- **Key fields**: `realizedLpFeePct` (LP fee percentage), `appliedRelayerFeePct` or `relayerFeePct` (relayer fee percentage), `fillAmount` (amount filled), `destinationToken` (token address)

### Component C: V2.5 and V3 bridge fees
- **Purpose**: Calculate fees for newer protocol versions by comparing input and output amounts in USD
- **Logic**: Process `FilledRelay` events from v2.5 contracts and `FilledV3Relay` events from v3 contracts across all supported chains. Map chain-specific token addresses to L1 equivalents using hub pool routing data from `SetPoolRebalanceRoute` events. Apply decimal correction using token metadata to normalize `inputAmount` and `outputAmount` (using `updatedOutputAmount` when available). Convert normalized amounts to USD using end-of-day price feeds matched by timestamp and L1 token address. Calculate fees as the difference between USD input amount and USD output amount. Filter out invalid transactions including specific denied relayers and transaction hashes that caused erroneous spikes.
- **Key fields**: `inputToken` and `outputToken` (chain-specific token addresses), `inputAmount` and `updatedOutputAmount` (token amounts), `l1Token` (L1 equivalent address), `price_usd` (end-of-day USD price)

### Final aggregation
- **Combining components**: Union all fee calculations from v1, v2, and v2.5/v3 components into a single dataset grouped by daily timestamp and origin chain
- **Currency conversion**: V1 and V2 fees undergo decimal correction using token metadata followed by USD conversion using end-of-day price feeds. V2.5/V3 fees are already converted to USD during component calculation
- **Time aggregation**: Truncate all timestamps to daily boundaries (`timestamp_trunc(block_timestamp, day)`) and group by day, chain, and business metadata (market sector: 'bridges', business segment: 'mint_and_burn')
- **Final calculation**: Sum all fee amounts by day and chain, apply chain availability filters to ensure only supported chains are included, and use `finalize_metric_fees_supply_side` macro to standardize schema and fill any data gaps

*This methodology was automatically generated by Token Terminal's methodology analyzer.*

Portion of fees distributed to service providers or supply-side participants.

AcrossACX

Supply-side fees

Supply-side fees

Competitive landscape

Chain breakdown