Sovereign PoS Stack Survey — Final Scoring, Ranking, and Deep Analysis

• Definition: Local web server bridging hardware wallets to BTCPay via HWI; designed to keep signing keys off the BTCPay server. (GitHub README)
• Supply-chain discipline: Official docs describe verifying release signatures for downloaded binaries. (How to verify)

Score drivers: Extremely high BTC purity and strong sovereignty via key isolation. Included as a separate scored component because it materially changes the trust model of BTCPay deployments.

• Definition: Contactless NFC card payments over Lightning, backed by a “bolt card service” that receives merchant requests, applies rules, and triggers Lightning payments. (GitHub README)
• Self-hosting posture: The service software is explicitly described as hostable “for yourself and others.” (GitHub README)

Score drivers: Excellent physical-world UX and strong sovereignty when self-hosted with a self-controlled Lightning backend. Privacy depends on LNURL/card-service metadata and backend logging.

• Definition: Android PoS app enabling Cashu ecash “tap-to-pay.” (GitHub README)
• Repository warning: Described as “NOT a wallet,” acting as a terminal generating redemption tokens; README warns tokens must be redeemed in a Cashu wallet. (GitHub README)
• Custody statement: Website FAQ states Numo is custodial and supports withdrawals/threshold payouts. (Numo FAQ)

Score drivers: Very strong telos alignment (Bitcoin-only, ecash + NFC), excellent merchant UX, and high privacy characteristics from blind-signature ecash. Sovereignty is capped by mint-custody realities and mobile platform constraints.

• Definition: DIY device enabling offline LN payments, on-chain address generation from xpub, and LNURL-withdraw “meatbag ATM.” (GitHub README)
• Offline LN design: Uses LNURL-pay with an encrypted PIN/receipt mechanism. (GitHub README)
• On-chain mode: Generates fresh addresses from xpub; includes mempool verification QR. (GitHub README)
• Dependency: Uses LNbits LNURLDevice extension. (GitHub README)

Score drivers: Strong telos alignment as an offline-first hardware primitive; sovereignty and privacy depend on the backing LNbits deployment and Lightning backend choices.

• Definition: A lightweight Python server that sits on top of a Lightning funding source and provides isolated wallets, APIs, and extensions. (GitHub README)
• Funding sources: Wiki lists multiple backends (e.g., Core Lightning, LND, OpenNode, LNPay, etc.), emphasizing modularity. (Wiki)
• Extension surface: Extensions are central to LNbits; the extension registry and install flow are official. (Extensions, Extension install docs)
• Monetary contamination vector: The pegging extension explicitly describes synthetic stablecoin behavior via a centralized exchange mechanism. (Peghing extension)

Score drivers: Very powerful sovereign lab tool when self-hosted on a self-controlled Lightning node. Scores are capped by (a) the centralizing “mini-bank” deployment pattern and (b) extension ecosystem landmines (synthetic pegging, etc.).

• Definition: Browser PoS based on LUD-21 (LNURL-pay with verify) for instant, verifiable payments. (GitHub README)
• Non-custodial PoS surface: README states funds are never held in the PoS app and go directly to the specified LNURL. (GitHub README)
• Protocol base: LNURL LUD-21 “pay with verify” specification is public. (LUD-21)

Score drivers: Thin-client design is structurally clean: minimal extra trust beyond the underlying LNURL/LN backend. UX and maturity are modest compared to larger platforms and hardware stacks.

• Definition: PWA PoS built on Next.js; local storage uses IndexedDB and localStorage; payments via LUD-16/LUD-21 and NFC Web API. (GitHub README)
• Thin-client posture: Backend sovereignty depends entirely on the Lightning Address/LNURL target; PoS holds configuration locally. (GitHub README)

Score drivers: Architecturally clean local-first web PoS with minimal required infrastructure. Maturity is intentionally scored low due to small/young project profile (no releases published, limited adoption signal).

• Definition: PHP payment gateway implementing BTCPay Server’s Greenfield API; uses Cashu mints for Lightning invoices, reducing requirement for running a Lightning node. (GitHub README)
• Explicit risk posture: README labels the project as experimental and warns about loss-of-funds risk. (README)
• Custody statement: README states selected mints take custody until withdrawal; recommends own mint or auto-withdrawal. (README)
• Deployment target: Emphasizes shared PHP hosting (“upload and go”). (README)

Score drivers: Excellent privacy/telos potential via ecash, and strong synthetic-stack independence by avoiding VPS/Docker, but sovereignty is capped by mint custody and maturity is capped by explicit “experimental” status.

• Definition: Self-hosted POS using Cashu ecash with NFC tap-to-pay and Lightning, built for mobile devices. (README)
• Offline-first: README describes offline queuing and a local SQLite database. (README)
• Multi-terminal sync: Uses Nostr relays and provides a default set of public relays. (README)
• Explicit custody tradeoff: README compares direct Lightning self-custody vs Cashu custody (“trust mint”) and states the tradeoff is improved UX. (README)

Score drivers: Very strong telos alignment and merchant UX for ecash-first environments. Synthetic-stack independence and privacy are penalized due to multi-terminal sync over public relays (metadata + correlation surface), plus the unavoidable mint custody tradeoff.

• Definition: Lightning wallet that includes a PoS mode transforming the app into a cash register. (Google Play, App Store)
• Non-custodial claim: Store listings and Breez documentation describe a non-custodial design using lnd and Neutrino under the hood. (Google Play, Intro)
• Distribution choke points: Primary distribution is app stores. (Google Play, App Store)

Score drivers: Excellent UX and strong maturity, but structurally app-store-dependent and LSP-shaped. Under a sovereignty-first lens, the convenience upside does not offset synthetic-stack lock-in and surveillance surface.