Blitz Wallet

Blitz Wallet is a self-custodial Bitcoin wallet built by Blake Kaufman. The app has gone through several architectures: it started as a Lightning wallet on Breez SDK and Blockstream Greenlight, added Liquid and ecash balances, and most recently moved the entire wallet onto the Spark protocol. Across those changes, the wallet has kept the same shape: one balance behind a simple UI.

Simplicity of use is the difference between Bitcoin as a cypherpunk technology and Bitcoin as a monetary revolution.

—Blake Kaufman

Blitz runs on iOS, Android (also available on Zapstore), and as a Progressive Web App that works in any browser without an app store. It ships with an LNURL address for every user, Nostr Wallet Connect, support for multiple wallets per user, and localization into several languages. A built-in store and point-of-sale app round out the product, with integrations for The Bitcoin Company, PPQ AI, nadanada, and SMS4Sats so users can spend sats on gift cards, AI credits, VPN access, and SMS. A standalone Spark recovery tool works with any Spark wallet so users are never dependent on a single app.

Why fund it?

Self-custody on Lightning is still hard for non-technical users: inbound liquidity, channel management, and backups all get in the way. Blitz experiments with ways to hide that complexity while keeping users in control of their keys. As the first live reference implementation of Spark, Blitz also gives other wallet developers a concrete example to study.

OpenSats first funded Blitz in the sixth wave of Bitcoin grants in July 2024 and has renewed the grant since. For a longer write-up of recent work, see the Advancements in Bitcoin and Lightning Wallets impact report.

What's next?

Since shipping on the Apple App Store and Google Play in late 2025, Blitz has grown to over 5,000 users. Recent additions include Payment Pools for shared goals, Paylinks (URL-based payment requests that work with any wallet and accept BTC, USDT, or USDC), reclaimable gifting, Dollar Goals, and USDB (USD on Spark) with send, receive, and swap. Ongoing work covers bulk payments, payment requests between contacts, more Point-of-Sale improvements, and continued mobile-to-web feature parity so anyone with a browser can run a full Blitz wallet.