Cowrie Research

acinq

4 min read

ACINQ

  • Name: ACINQ
  • URL: https://acinq.co/
  • Category: Bitcoin Lightning software company / self-custodial wallet stack / mobile-and-server Lightning infrastructure operator
  • Tags: bitcoin-ecosystem
  • Summary: ACINQ belongs as an entity note, not a protocol note. The useful split is Eclair for server and routing nodes, lightning-kmp for mobile wallet logic, bitcoin-kmp for Bitcoin primitives, Phoenix for end-user distribution, and phoenixd for API-first payment servers. The practical control surface sits with the company packaging those layers, choosing defaults, and deciding how much Lightning operational complexity gets exposed versus abstracted away.
  • What it does:
    • Develops Eclair, a long-running Scala implementation of the Lightning Network for routing nodes and server-side deployments, with its own HTTP JSON API and operational documentation
    • Maintains lightning-kmp, a Kotlin Multiplatform Lightning implementation explicitly optimized for mobile wallets rather than routing nodes
    • Maintains bitcoin-kmp, a Kotlin Multiplatform Bitcoin library covering transaction creation, signing, verification, scripts, wallets, PSBT, Taproot, and related Bitcoin primitives
    • Operates Phoenix, a self-custodial Bitcoin wallet built by ACINQ for sending and receiving bitcoin over Lightning on iOS and Android
    • Publishes phoenixd, described as the server equivalent of the Phoenix mobile wallet, extending the same stack into Linux, macOS, and Windows/WSL deployments
    • Uses its open-source repo surface to expose both end-user and operator/developer layers, which suggests ACINQ is building a reusable Lightning software stack, not just a branded wallet app
  • Key claims:
    • The ACINQ homepage metadata describes ACINQ as “a Bitcoin technology company with a focus on the Lightning Network”
    • The Phoenix site metadata describes Phoenix as “The Bitcoin wallet from the future,” while the Phoenix README says it is a self-custodial Bitcoin wallet where users hold the keys and use Lightning for faster, cheaper payments
    • The Eclair README describes Eclair as a Scala implementation of the Lightning Network that follows the Lightning Network Specifications (BOLTs) and exposes a feature-rich HTTP API for application developers
    • The lightning-kmp README says it is a Kotlin Multiplatform implementation of the Lightning Network optimized for mobile wallets and explicitly distinguishes itself from Eclair, which is optimized for servers and routing nodes
    • The phoenixd README describes phoenixd as the server equivalent of Phoenix Wallet and links to its homepage and API documentation
    • The ACINQ GitHub org reinforces the platform reading by prominently surfacing Eclair, Phoenix, lightning-kmp, bitcoin-kmp, phoenixd, and related plugins and libraries instead of only a single wallet client
  • Whitepaper: No canonical standalone ACINQ whitepaper or litepaper surfaced in this pass. The clearest current sources of truth are the official ACINQ and Phoenix sites plus ACINQ’s public repositories and READMEs for Eclair, Phoenix, lightning-kmp, bitcoin-kmp, and phoenixd; see ../whitepapers/acinq-primary-sources-2026-04-30.md.
  • Sources:

Internal linkages

  • Legacy project-layer alias preserved for old links: acinq.
  • Keep the linkage budget short.
  • Project-layer notes that should stay separate: eclair, phoenix-wallet, and phoenixd.
  • Useful operator-shape contrast where the company line matters less than the product note: breez.

Protocol / company boundary

  • eclair is the server-node and operator-backend note: routing-node behavior, HTTP / CLI control, Bitcoin Core coupling, and the general-purpose Lightning daemon surface.
  • phoenix-wallet is the end-user mobile-wallet note: splicing, inbound-liquidity policy, swap behavior, fee legibility, and the trust-minimized phone-node operating model.
  • phoenixd is the specialized payment-daemon note: API-first backend packaging, auto-liquidity, webhooks, Bolt12 offers, and self-custodial server payments.
  • This company note is the packaging boundary above those layers: the organization deciding how much Lightning complexity gets hidden, which defaults travel from shared code into Phoenix and phoenixd, and how the Eclair / lightning-kmp / bitcoin-kmp stack is distributed and documented as one coherent ACINQ family.
  • That split matters because how does Phoenix splice a channel?, how does phoenixd expose inbound-liquidity policy?, and who is shaping the shared software lineage and default operating posture across all of them? are related but not identical questions.

Control surface

  • Bitcoin and Lightning are still the rails. ACINQ matters because it decides how much of that operational mess gets exposed versus packaged away.

  • The leverage sits in stack boundaries and defaults: Eclair for server nodes, lightning-kmp for mobile logic, Phoenix and phoenixd for distribution, plus the liquidity, backend, and API choices wrapped around them.

  • The company boundary is especially useful when several different ACINQ products are really one shared software lineage with different packaging and operator assumptions above it.

  • Treat ACINQ as a vertically integrated Lightning software shop, not as a generic wallet brand and not as a new protocol.

  • Last reviewed: 2026-08-10 UTC

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