Users deposit and lock assets on Ethereum in exchange for an equivalent amount of a corresponding token on zkSync Era. Conversely, users can withdraw assets from zkSync Era in exchange for the same amount on Ethereum.

zkSync Era Bridge is an asset bridge built on Ethereum and zkSync Era. zkSync Era Bridge was developed by Matter Labs and launched in 2023.

Matter Labs team owns and governs the protocol. Matter Labs' investors include a16z, Lightspeed Venture Partners, Blockchain Capital, etc.

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zkSync Era Bridge

# zkSync Era Bridge Fees Methodology

## 1. Overview

The zkSync Era Bridge fees metric measures the fees charged by the zkSync Era Bridge protocol for cross-chain transfers between Ethereum and zkSync Era. This metric is calculated by setting fees to zero across all time periods, reflecting zkSync Era Bridge's business model of providing fee-free bridging services to users. The metric maintains the same temporal and dimensional structure as the transfer volume metric to ensure consistency in reporting.

## 2. Data sources

The methodology uses the following data sources:
- **Ethereum blockchain events**: Parsed zkSync Era bridge contract events including `DepositInitiated`, `WithdrawalFinalized`, `NewPriorityRequest`, and `EthWithdrawalFinalized` events
- **Bridge contract data**: Events from L1ERC20Bridge and Diamond contracts on Ethereum that handle ERC20 tokens and ETH transfers respectively
- **Transaction metadata**: Block timestamps, transaction hashes, and log indices from Ethereum blockchain
- **Token information**: Token addresses and contract addresses for both ETH and ERC20 tokens
- **Temporal data**: Daily aggregation timestamps derived from blockchain event timestamps

## 3. Step-by-step calculation

### Component A: Transfer volume data extraction
- **Purpose**: Provides the dimensional and temporal structure for the fees metric
- **Logic**: Extracts timestamp information, chain identifiers, and product classifications from the zkSync Era Bridge transfer volume metric. This includes daily timestamps, chain IDs for Ethereum, product IDs, and timestamp grain specifications. The transfer volume metric itself combines deposit and withdrawal events from zkSync Era bridge contracts on Ethereum.
- **Key fields**: `timestamp` (daily aggregation), `timestamp_grain` (set to 'day'), `product_id`, `chain_id` (identifying Ethereum)

### Component B: Fee value assignment
- **Purpose**: Sets the fee amount for all bridge transactions
- **Logic**: Hardcodes the fees value to zero for every record, reflecting zkSync Era Bridge's business model of not charging users fees for cross-chain transfers. This is applied uniformly across all time periods, chains, and token types.
- **Key fields**: `fees` (set to 0 for all records)

### Final aggregation
- **Combining components**: The temporal and dimensional data from transfer volume is combined with the hardcoded zero fees value to create complete fee records for each day and chain combination
- **Currency conversion**: No currency conversion is required since fees are zero
- **Time aggregation**: Daily boundaries are maintained from the source transfer volume data, ensuring consistent reporting periods
- **Final calculation**: The fees metric equals zero for all time periods, representing zkSync Era Bridge's fee-free service model. The finalize_metric_fees macro ensures proper schema compliance and fills any temporal gaps while maintaining the zero fee values.

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

Total value users pay to use a protocol (gross fees, user-paid fees).

zkSync Era Bridge

Fees

Fees

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Chain breakdown