- Published on
Thirteenth Wave of Bitcoin Grants
- Authors
- Name
- OpenSats
- Name
- Arvin
- @arvin
OpenSats is pleased to announce the thirteenth wave of grants from our General Fund for eight open-source projects that close privacy gaps, streamline self-custody, and help fortify Bitcoin's technical core.
This round includes five first-time project grants and three grant renewals, with every satoshi going straight to the developers and maintainers of each respective project.
First-time project grants:
Grant renewals:
Each project addresses a specific need—from drop-in Tor libraries and Silent Payments coordination to hardened live-OS builds, Nginx modules that allow for seamless monetization, and merchant-ready e-cash wallets—strengthening privacy and usability across the stack.
The ability to support these projects is made possible by the generosity of our donors. If you would like to help us continue funding important advancements within the Bitcoin ecosystem, please consider donating to the General Fund.
Let's dive in to see how each project is contributing to the future of Bitcoin.
KMP-Tor
KMP-Tor is a Kotlin Multiplatform (KMP) library that embeds reproducible Tor binaries alongside a lightweight runtime, letting Android, JVM, Kotlin/Native (Linux, macOS, iOS), and Node developers integrate Tor directly into their applications. The project handles Tor's event loop and packaging complexities, providing projects like Sparrow Wallet, BitBanana, and Sphinx Chat with a single dependency for privacy‑preserving network connectivity. For instance, Sparrow upgraded to Tor 0.4.7.13 by simply updating its kmp‑tor version.
With support from this grant, maintainer Matthew Nelson will extend hardware coverage in the companion kmp‑tor‑resource repository—adding riscv64 builds for Linux‑libc, aarch64/riscv64/x86/x86_64 for Linux‑musl, and aarch64/x86/x86_64 for FreeBSD—and complete support for Tor's roughly 350 configuration options (about 250 implemented today). These milestones will keep kmp‑tor a dependable drop‑in Tor solution across the Bitcoin ecosystem.
Repository: 05nelsonm/kmp-tor
License: Apache 2.0
DTails
DTails is an open‑source remastering tool for Debian Live‑based operating systems, such as Tails, a privacy‑focused OS designed for security and anonymity. Using a straightforward GUI, it opens a stock ISO, lets users add or remove Bitcoin and privacy software such as Sparrow Wallet, Liana, Bisq, SeedTool, Specter Desktop, and more, then rebuilds a bootable ISO in minutes with no persistence required. By automating package selection and ISO assembly, DTails removes barriers to running hardened Bitcoin toolsets on Tails.
With support from this grant, maintainer DesobedienteTecnologico will release a redesigned GUI, implement automated diffing that highlights every file changed between the stock and customized ISOs, and refactor the codebase for reliability. If there is enough community demand, the effort will expand into a dedicated Tails fork pre‑bundled with Bitcoin tools, complete with its own website and documentation.
Repository: DesobedienteTecnologico/dtails
License: GPL‑3.0
Sats App
Sats App is a native Cashu wallet project that combines a simple interface with new Swift- and Kotlin-based bindings to the Cashu Development Kit (CDK). Powered by cdk_flutter, it exposes the CDK's Rust core to iOS and Android so an application can create a seed, connect to a mint, and send/receive e-cash. The current code already covers seed creation, mint connection, and token send/receive, giving merchants a straightforward path to accept e-cash without extra setup.
With support from this grant, the project will release fully documented Swift and Kotlin bindings, launch TestFlight and closed Android betas with local token storage, and publish public builds in the App Store and Google Play. Efforts will then shift to remote cloud backup, NFC tap-to-pay, and other merchant-centric features—advancing toward the open-source "Cash App" experience for Cashu.
Repository: davidcaseria/cdk_flutter
License: MIT
ngx_L402
The ngx_L402 project is a lightweight NGINX module that brings bitcoin-based payments directly to the web server. Written in Rust and delivered as a native plug-in, it enforces the L402 authentication standard from Lightning Labs and also accepts Cashu tokens for e-cash redemptions. By moving payment checks inside NGINX instead of relying on Aperture as a separate reverse proxy, it cuts latency, removes extra infrastructure, and lets any service behind NGINX gate routes with bitcoin or Lightning payments out of the box. Predyx and other early adopters are already testing the module, and community feedback is guiding new feature requests.
With support from this grant, the roadmap will begin with core parity and stabilization: gRPC support, time-bounded and rate-limited macaroons, enhanced logging, and a Docker image for quick deployment. It then moves to Cashu security upgrades such as dynamic pricing, scheduled redemptions, mint allowlists, and local double-spend protection, followed by Redis-backed token storage, Lightning Node Connect integration, and Tor support for .onion nodes. If time and resources allow, the team will also add Core Lightning and Eclair support, publish tutorial materials, and explore ports to other reverse proxies, all to make ngx_L402 the default tool for Lightning-based API monetization.
Repository: DhananjayPurohit/ngx_l402
License: MIT
Silent Payments Shepherd
Silent Payments Shepherd is a coordination hub that tracks, documents, and unblocks every moving part of the Silent Payments (BIP-352) ecosystem. Project maintainer MacGyver curates a live developer dashboard, keeps specifications in sync, and collaborates with wallet teams to integrate Silent Payments—reusable-address that let senders create one-time Taproot outputs without any on-chain or out-of-band signalling, improving privacy for payroll and other payment workflows. By pairing project-management discipline with hands-on coding, the role of Shepherd gives Silent Payments the cohesion it needs to move from prototypes to production-ready software.
With support from this grant, the project will implement a five-phase roadmap: revive development and publish a public progress tracker; harden cryptography libraries and integrate wallet implementations in Bitcoin Core, Electrum, and Sparrow; define outsourced scanning and vending services so light clients can operate efficiently; run guided pilots with real bitcoin to validate the entire workflow; and work with exchanges to standardize human-readable reusable addresses. Each milestone removes a critical blocker on the path to mainstream adoption of Silent Payments across the Bitcoin stack.
Repository: macgyver13/silent-payments-hub
License: MIT
From reproducible Tor binaries and live-OS hardening to Silent Payments stewardship and rigorous Core review, this thirteenth wave strengthens Bitcoin's technical foundation and broadens user choice.
Every grant application goes through a mission-aligned review process. If you're building free and open-source Bitcoin software that advances decentralization and user sovereignty, we invite you to apply for funding.
Our work is made possible by the generosity of our donors. If you'd like to help make the future of free and open-source Bitcoin development more sustainable, consider setting up a recurring donation to one of our funds. Any amount helps.