Hemi is a modular blockchain protocol designed to connect Bitcoin and Ethereum as parts of a single network. It combines Ethereum-style programmability with Bitcoin state awareness, allowing developers to build applications that can use Bitcoin data, Bitcoin-native assets and Ethereum-compatible smart contracts within the same environment.

The core component of Hemi is the Hemi Virtual Machine (hVM), which is described as an Ethereum Virtual Machine that includes an indexed Bitcoin full node. This lets smart contracts access Bitcoin data such as UTXOs, balances, transaction history, block headers, confirmations, fee statistics, Ordinals, BRC-20 activity and Rune-related data.

Hemi also uses Proof-of-Proof (PoP), a mechanism where Hemi state data is published to Bitcoin. This allows Hemi transactions to inherit Bitcoin-level security after a finality period. The network reaches Bitcoin finality after nine Bitcoin blocks, or around 90 minutes on average, when no competing Hemi chain segment has been published to Bitcoin.

HEMI is the native token used to support activity across the Hemi Network. Network participants are rewarded in native tokens for roles such as sequencing, PoP mining, publishing Hemi data to Ethereum and challenging invalid publications. The token is also used for staking by participants that operate sequencers or publishers.

Hemi supports a dual-asset gas model, allowing users to pay fees in ETH or in the native token. ETH gas payments are converted into native tokens through on-chain decentralised exchanges before being distributed to the relevant network participants.

The network is designed to support several use cases, including:

• Bitcoin-aware decentralised applications, known as hApps
• Bitcoin and Ethereum asset transfers through Tunnels
• Bitcoin-secured lending markets and decentralised exchanges
• BTC, Ordinals and BRC-20 asset markets
• non-custodial Bitcoin escrow services
• Bitcoin-secured chain infrastructure through Chainbuilder
• hChains that use Hemi’s Bitcoin-Security-as-a-Service model

Hemi’s Tunnel system is used to move assets between Hemi, Bitcoin and Ethereum. Bitcoin assets can be represented on Hemi through vault systems, while Ethereum assets can move through rollup-style validation contracts. This allows Bitcoin-native assets to be used in Hemi applications and, through Hemi, in the wider Ethereum ecosystem.

Hemi uses several network roles and components:

• hVM: an EVM environment with indexed Bitcoin state access
• Hemi Bitcoin Kit (hBK): smart contracts that make Bitcoin data easier for developers to query
• Bitcoin-Secure Sequencer (BSS): manages Hemi consensus and communication with Ethereum
• PoP Miners: publish Hemi state information to Bitcoin
• Bitcoin Finality Governor (BFG): tracks Bitcoin finality and detects PoP publications
• Publishers: publish Hemi state roots and block data to Ethereum
• Challengers: monitor Publisher activity and submit fault proofs for invalid publications
• Tunnels: move assets between Hemi, Bitcoin and Ethereum