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 Transfer volume Methodology

## 1. Overview

zkSync Era Bridge transfer volume measures the total daily USD value of all token transfers facilitated by the zkSync Era Bridge protocol. This includes both deposits (transfers from Ethereum L1 to zkSync Era L2) and withdrawals (transfers from zkSync Era L2 back to Ethereum L1). The metric captures the bidirectional flow of value through the bridge, providing insight into the bridge's daily transaction volume and usage patterns.

## 2. Data sources

The calculation relies on several raw blockchain data sources:

- **Ethereum event logs**: Parsed bridge contract events from the zkSync Era Bridge smart contracts deployed on Ethereum
- **Bridge deposit events**: `DepositInitiated` events from the L1ERC20Bridge contract capturing ERC20 token deposits, and `NewPriorityRequest` events from the Diamond contract capturing ETH deposits
- **Bridge withdrawal events**: `WithdrawalFinalized` events from the L1ERC20Bridge contract capturing ERC20 token withdrawals, and `EthWithdrawalFinalized` events from the Diamond contract capturing ETH withdrawals  
- **Token metadata**: Token contract information including decimal places for proper amount normalization
- **End-of-day price feeds**: Daily closing prices for converting token amounts to USD values

## 3. Step-by-step calculation

### Component A: Bridge deposits

- **Purpose**: Captures all L1 to L2 token transfers through the zkSync Era Bridge
- **Logic**: Extracts deposit events from two Ethereum contract event types. For ERC20 tokens, processes `DepositInitiated` events from the L1ERC20Bridge contract, using the `amount` field for transfer volume and the `l1Token` field to identify the specific token being deposited. For ETH deposits, processes `NewPriorityRequest` events from the Diamond contract, extracting the amount from the `transaction.reserved[0]` field and using a hardcoded WETH contract address as the token identifier. All events are timestamped to the block time and include transaction hash and log index for uniqueness
- **Key fields**: `amount` (transfer volume), `l1Token` (token address for ERC20), `transaction.reserved[0]` (ETH amount), `block_timestamp` (event timing), `transaction_hash` and `log_index` (event identification)

### Component B: Bridge withdrawals

- **Purpose**: Captures all L2 to L1 token transfers through the zkSync Era Bridge  
- **Logic**: Extracts withdrawal events using the same dual-contract pattern as deposits. For ERC20 tokens, processes `WithdrawalFinalized` events from the L1ERC20Bridge contract, using the `amount` field for transfer volume and the `l1Token` field for token identification. For ETH withdrawals, processes `EthWithdrawalFinalized` events from the Diamond contract, using the `amount` field and the same hardcoded WETH address. The structure mirrors the deposits component but captures the opposite transfer direction
- **Key fields**: `amount` (transfer volume), `l1Token` (token address for ERC20), `block_timestamp` (event timing), `transaction_hash` and `log_index` (event identification)

### Final aggregation

- **Combining components**: Deposits and withdrawals are combined using a union operation to create a comprehensive dataset of all bridge transfers in both directions. Each record maintains its directional context while contributing to the total transfer volume
- **Currency conversion**: Token amounts are converted to USD using end-of-day price feeds, with automatic decimal adjustment based on each token's decimal configuration. ETH amounts use the WETH price reference for conversion
- **Time aggregation**: All transfer timestamps are truncated to daily boundaries, grouping all transfers within each calendar day regardless of the specific time they occurred
- **Final calculation**: The daily transfer volume is the sum of all USD-converted deposit and withdrawal amounts for each day. Missing days in the time series are filled with zero values to maintain continuity, and the final metric represents the total value flowing through the zkSync Era Bridge on each day

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

Total value of assets moved across chains through a bridge.

zkSync Era Bridge

Transfer volume

Transfer volume

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Chain breakdown