Alpen

• Name: Alpen
• URL: https://www.alpen.org/
• Category: Bitcoin validity rollup / EVM-compatible execution layer / BitVM2 bridge and orchestration infrastructure
• Tags: bitcoin-ecosystem ethereum-ecosystem
• Summary: Alpen is a Bitcoin-oriented execution stack from Alpen Labs that pairs an EVM-compatible validity-rollup environment with a separate orchestration layer called Strata, a BitVM2-based BTC bridge, and explicit account-abstraction, proving, and node-running surfaces. The project is notable less as a generic Bitcoin L2 marketing page and more as a fairly legible docs-and-code-first attempt to build a Bitcoin-settled zkEVM-style environment, while openly documenting that the current network still runs on a private Bitcoin signet with centralized sequencer and bridge-operator assumptions. That mechanism-layer cut is still worth keeping separate from alpen-labs, which is the cleaner note for the current company-operated service shell around sequencing, bundler workflow, docs, and security/disclosure handling.
• What it does:
  • Offers an EVM-compatible blockchain environment where Ethereum-style smart contracts can be deployed with Prague-era compatibility, excluding type-3 transactions and blob-related upgrades
  • Splits the stack into an execution layer (Alpen) and an orchestration layer (Strata), with a modified Engine API connecting the two so Bitcoin-bridge events and rollup coordination can be handled explicitly
  • Exposes builder-facing infrastructure including public RPC, ERC-4337 bundling, contract-deployment guides, a CLI, and public node-operator documentation
  • Uses Bitcoin as the source of truth for checkpoints and validity-proof commitments, while the current testnet behaves more like a commit chain because full onchain data availability is not yet live
  • Implements an enshrined BTC bridge based on BitVM2, with operator bonds, fixed-denomination deposits and withdrawals on testnet, and challenge-response logic for incorrect withdrawal claims
  • Maintains a meaningful public engineering and security surface via the main repo, docs, audit log, and Immunefi bounty program
• Key claims:
  • The intro docs and repo README describe Alpen as a “work-in-progress EVM-compatible validity rollup on bitcoin”
  • The docs say that if a developer can deploy a smart contract to Ethereum, they can deploy it to Alpen with no code changes, and the compatibility page says Alpen is EVM-compatible up to Prague excluding type-3 transactions and EIP-4844-style blob upgrades, making it a Type 2.5 zkEVM
  • The system-architecture docs say applications can interact through a full node, ERC-4337 bundler, and Bitcoin bridge flow, while full nodes and bundlers can be run by anyone even though the sequencer is currently centralized
  • The bridge docs say the Strata bridge is based on BitVM2 and aims for safety/liveness with a single functional operator rather than an honest-majority multisig assumption
  • The bridge docs currently document fixed 10 BTC deposit and withdrawal denominations on testnet, a 0.01 BTC withdrawal fee, and a challenge period measured in Bitcoin blocks
  • The docs explicitly note that the current network runs on a private Bitcoin signet, stores state commitments rather than full Alpen state data on Bitcoin, and should presently be understood as more commit-chain-like than a finished mainnet rollup
  • The security page says mainnet v1 contracts are under active audit and that the listed public reports cover alpha/testnet implementations
• Whitepaper: No canonical standalone Alpen whitepaper or litepaper surfaced in this pass. The strongest first-party sources were the official docs corpus, system-architecture and bridge documentation, compatibility docs, public repo README, and security page. The bridge docs reference the external BitVM2 paper as design context, but that is not an Alpen-specific whitepaper. See ../whitepapers/alpen-primary-sources-2026-05-02.md.
• Sources:
  • https://www.alpenlabs.io/
  • https://docs.alpenlabs.io/
  • https://docs.alpenlabs.io/how-alpen-works/system-architecture
  • https://docs.alpenlabs.io/how-alpen-works/bitcoin-bridge
  • https://docs.alpenlabs.io/how-alpen-works/strata-design-rationale
  • https://docs.alpenlabs.io/how-alpen-works/comparing-strata-and-ethereum
  • https://docs.alpenlabs.io/build-alpen-apps/deploying-alpen-smart-contracts
  • https://docs.alpenlabs.io/community/security
  • https://raw.githubusercontent.com/alpenlabs/alpen/main/README.md

Internal linkages

• Company / operator boundary around the current centralized service shell, official bundler workflow, implementation/docs path, and security/disclosure handling: alpen-labs.
• Closest Bitcoin-EVM execution siblings worth reading next: citrea and bitlayer.
• Bridge-mechanism baseline beneath the same trust story: bitvm-bridge.

Comparison cut

• Keep this note on the protocol and product mechanics: Alpen execution, Strata orchestration, the bridge design, data-availability and settlement path, and the current signet-era trust assumptions.

• Use alpen-labs when the real question is who currently operates the sequencers, provides the easiest account-abstraction entrypoint, owns the public security workflow, or otherwise shapes the live operator shell above the protocol design.

• Last reviewed: 2026-08-08 UTC