Published on

Third Wave of Bitcoin Grants


One aspect of Bitcoin that is often overlooked is that, no matter how crazy the news cycle (or the mempools) might be, Bitcoin marches on, unbothered. Every 10 minutes, transactions are being settled. Every 10 minutes, the network focuses on a new block. Every 10 minutes, the timechain is flourishing. It is the constant signal in an increasingly noisy world.

While OpenSats doesn't operate in 10-minute intervals like Bitcoin does, we aim to filter the signal from the noise and consistently execute just the same. Our mission is to support and maintain a sustainable ecosystem of funding for free and open-source projects and contributors, especially Bitcoin-related projects and projects that help Bitcoin flourish. In other words: we want Bitcoin's open-source contributors to flourish alongside Bitcoin and have them unbothered, moisturized, happy, and focused.

We are proud to announce 10 new grants to impactful projects in the Bitcoin space. In no particular order, here they are:

All of the above grants are sourced from our General Fund, which is funded by generous donors like you. If you want to help us support free and open-source projects please consider donating to the fund:

This brings the total number of grants given by OpenSats to 69, including the eight long-term support grants we announced previously, as well as the 32 grants announced for nostr.

As always, let's take a closer look at the projects to understand what they are about and how they align with our mission.


Clams is an interface for CLN nodes that establishes a secure and encrypted connection directly through the Lightning Network. After user-defined permissions are added, the app can execute various functions on the node like sending and receiving payments.

Payment options include Keysend, BOLT11 invoices, LNURL, and BOLT12 offers. Other notable features include lightning channel management and a bookkeeping dashboard.

The app is a Progressive Web App (PWA) meaning it works on all devices that have a browser. It has a mobile experience that is similar to Zeus. The desktop version is more advanced, with a UX akin to Ride The Lightning. Clams is privacy-focused, does no logging, has no trackers, and all data stays on the user's device.

Repository: clams-tech
License: MIT

Fully Noded

Fully Noded is the first app for iOS and macOS that allows users to connect to their node via RPC over Tor for a truly self-sovereign Bitcoin experience. It utilizes PSBTs and descriptors to expose all of the excellent wallet functionality that Bitcoin Core offers. It supports BIP39 seeds, has easy integration with hardware signing devices, and is easy to use when compared to managing funds with bitcoin-cli.

The Fully Noded stack has the potential to make “one-click” self-sovereign Bitcoin usage a thing, as it is non-custodial and private by default.

Repository: Fonta1n3/FullyNoded
License: MIT

Validating Lightning Signer

Validating Lightning Signer (VLS) is an open-source project whose goal is to improve the security of the Lightning Network. Currently, the user's Lightning private keys are stored on the Lightning node itself. This poses a risk: if someone manages to hack into a node, they could steal the user's Bitcoin. It's like leaving your money in a vault but hanging the key on the vault's door.

VLS brings to Bitcoin Lightning what signing devices brought to Bitcoin: improved security via a reduced attack surface. In the future, VLS plans to implement multisig support, further improving security for Lightning Network users.

Repository: lightning-signer/validating-lightning-signer
License: Apache 2.0

Fedimint Lightning Gateway

Fedimint is an open-source framework for creating federated applications. Fedimints have the ability to custody bitcoin on behalf of clients of the federation and issue e-cash in return. Ecash transfers between participants of the federation can be done with almost perfect privacy since notes are transferred between clients using blind signatures.

Fedimints can also accept and send payments over Lightning using a Lightning Gateway. The Lightning Gateway provides a swap service between ecash notes of a federation and the broader Lightning network. Lightning Gateways are the glue that allows Fedimints to participate in the broader Bitcoin ecosystem. They abstract away the details of Fedimints and expose a user experience that feels like using a Lightning wallet.

The Lightning Gateway portion of Fedimint is important since it provides the connection between federations as well as to the broader Lightning network. Without Lightning support, the utility of federations is limited, since transactions can only be facilitated among clients of the federation. The Lightning support opens up Fedimint to the rest of the Bitcoin ecosystem. A client of Fedimint can pay to and receive from anything that "speaks" lightning.

Repository: fedimint/fedimint
License: MIT

Pickhardt Payments plugin for Core-Lightning

Pickhardt Payments is a novel payment routing strategy for the Lightning Network, originally developed in 2021 by Rene Pickhardt and Stefan Richter (

The method is based on a Bayesian description of the liquidity state of channels, with the precise allocation of liquidity unknown by the nodes of the network. An optimally reliable Multipath Payment (MPP) can be constructed by solving a Minimum Cost Flow (MCF) problem, where the cost function weights the probability of path failures due to insufficient liquidity.

The implementation of the Pickhardt-Richter method promises to bring a huge leap of improvement in the payments layer of the Lightning Network without the need to change the protocol's basic rules. From the users' point of view, it'll allow for a faster payment experience and fewer chances of payment failures.

Repository: lagrang3/lightning
License: BSD-MIT


BitBanana aims to provide the best User Experience for remote Lightning Node Management on Android. Additionally to managing the node, BitBanana allows its users to access the wallet functionality of their node in everyday situations. The focus of the app is remote management, which makes it a great open-source tool for node operators. The app was originally known as "Zap Android" before it was forked and rebranded.

Repository: michaelWuensch/BitBanana
License: MIT

Crack the Orange

Crack the Orange is an educational effort that is building a cohort of Bitcoin educators. The current goal is to train a total of 100 educators, community builders, and human rights activists per year. It is estimated that each of these individuals will onboard another ~10 peers in their communities with the knowledge acquired, spreading Bitcoin knowledge organically and peer-to-peer.

Any educational material produced by the project under this grant will be made publicly available and published under a permissive license that is appropriate for the content, i.e. one of the free licenses listed at

Repository: anitaposch/cto
License: MIT

Bitcoin Core App

The Bitcoin Core App is a modern and cross-platform UI designed by the Bitcoin Design community. It features new backend models that unravel the technical locks that the current Core GUI is plagued with, all without disturbing the need to further modularize the different components of Bitcoin Core.

The effort aims to keep Bitcoin Core accessible to run, and the features that full-node software can provide are easy and intuitive to use by non-technical people. Additionally, by exploring how Core behaves on mobile devices, we can reshape how we think about full-node software and further democratize enforcement of the network rules to those with mobile devices. With Core running as a background process on phones and tablets, apps and services can be built to use the local node instead of relying on remote nodes or a centralized server.

Repository: bitcoin-core/gui-qml
License: MIT


Krux is a free and open-source firmware that enables anyone to build their own Bitcoin signing device via off-the-shelf parts. It runs on Kendryte K210 Risk-V-based devices such as the M5StickV and Maix Amigo, converting them into air-gapped devices that can sign transactions for single and multisig wallets. Krux can also sign messages and has easy-to-use tools to help with the creation and loading of wallet backups.

Users can choose to buy a ready-to-use device—where all they need is to flash the firmware—or make a DIY version themselves. Krux can also run, mainly for educational purposes, on PCs and Android devices.

Repository: selfcustody/krux
License: MIT / Apache 2.0


Vexl is a free and open-source mobile app giving its users a simple, accessible, and safe way to trade bitcoin as it was intended: peer-to-peer and without KYC. Vexl is a non-profit, takes no fees from the trades that are happening on the platform, and doesn't store any user data.

The mission of Vexl is to make peer-to-peer and non-KYC bitcoin accessible to anyone without the need to go through a trusted third party.

Repository: vexl-it/vexl
License: GPL-3.0

We have received a large number of applications over the last months, which is a great signal on its own. If you are working on an open-source project that aligns with our values, don't hesitate to apply for funding. We are constantly sorting through applications and we try our best to select the most promising and most impactful proposals.

Thank you for your continual and generous support. As we don't take a cut from donations to open-source projects, we couldn't be doing what we are doing without your help. If you want to help us cover our operational expenses, please consider donating to our operations budget.