Express is a trust-minimized rollup that enables fast and cheap EVM transactions that settle through bitcoin and use natively bridged BTC for canonical gas fee.

Features and Guarantees

Express will have the following features, targets and guarantees for the first version of the Public Testnet release.

Features:

• EVM-equivalent ZK execution environment
• Instant pre-confirmations (~250 ms on average)
• Native bitcoin bridge
• Bridged BTC as fee token
• Ethereum-compatible RPC interface
  • Full compatibility with Ethereum https://github.com/ethereum/execution-specs
  • Additional rollup-specific RPCs (eg. providing granular transaction statuses and instant soft confirmation)
• Secure and trustless light/mobile clients
  • The rollup nodes do not execute transactions; they verify the execution. This allows rollup light clients that have no trust assumption on the rollup full nodes.
• Account abstraction
• Data Availability (DA) on bitcoin

Performance targets

• Throughput: > 10 tx/s
  • Will move towards Validium/Volition models (for later phases of Testnet) that can provide significantly higher throughput
• Pre-confirmation: ~ 250 ms on average