Node Design & Architecture

Sova Execution Client (sova-reth)

A customized EVM execution engine built using the Reth SDK, extended to support native Bitcoin precompiles and Bitcoin transaction tracing. It enforces Bitcoin finality through direct coordination with the Sentinel which traces state updates tied to BTC transactions and ensure the state on Sova accurately reflect the state on Bitcoin.

Consensus Client (op-node)

The canonical Optimism consensus client responsible for sequencing, block building, and L2-to-L1 rollup logic. On the sova network this service has the very important job of anchoring each Sova block to a Bitcoin by including confirmed Bitcoin block headers in Sova blocks.

Bitcoin Core

Each validator connects to a full Bitcoin node. This ensures that all Bitcoin-related operations (e.g. tx confirmation, block hash validation, UTXO availability) are verifiable directly from the Bitcoin network without having to trust the sequencer's Bitcoin connection.

Bitcoin Finality Provider (sentinel)

An off-chain database-backed service that tracks the confirmation status of Bitcoin transactions. It locks or reverts contract storage slots based on whether associated BTC transactions have been confirmed on-chain. Critical for enforcing 1:1 BTC-sovaBTC minting guarantees. Every validator runs the sentinel service alongside their execution client and Bitcoin node.

Sequencers

Sequencers on the Sova Network are responsible for block production, transaction ordering, and coordination of Bitcoin-related operations. In addition to executing EVM transactions, Sova sequencers play a unique role: they operate the network’s Signing Service API, which securely generates Bitcoin transactions during user withdrawals.

Bitcoin UTXO Indexer

An indexer which tracks all spendable UTXOs associated with Sova’s native deposit address and third party bitcoin addresses. All UTXOs that are tracked are spendable by the network for servicing user BTC withdrawals. It provides a real-time, block-by-block UTXO lookup API used by sova-reth to construct valid Bitcoin transactions during withdrawals.

Signing Service API

A restricted signing gateway used exclusively by sequencer nodes. It handles multi-input Bitcoin transaction signing and ensures signatures comply with consensus rules and proof-of-reserve integrity. The signing service is designed such that it does not use a single public/private key pair and instead sources signatures for a host of trusted custodians.

Deposit Transaction with Slot Locking Flow Diagram

Scenario: Doublespend Bitcoin transaction