Spiral Blockchain Engineer

Spiral (formerly Square Crypto) builds and funds free, open-source projects that advance the use of bitcoin as a tool for economic empowerment. The core team is mainly focused on contributing to the Lightning Development Kit (LDK), a tool that simplifies how developers add the Lightning Network – fast, cheap, global bitcoin payments – to applications. In addition, Spiral’s wildly successful grant program supplies funding to dozens of FOSS (free and open-source) bitcoin developers, designers, PMs, and educators all around the world. .

The Role

We’re looking to grow the six-person engineering team that exclusively works on developing the Lightning Development Kit (LDK) .  

LDK is a comprehensive open-source project that lets developers efficiently build Lightning applications. It includes a full implementation of the Lightning Network protocol written in Rust, APIs, language bindings, demo apps, and more. LDK is used by dozens of projects worldwide, including Lightspark, Cash App, Alby, and BitKit.  

The LDK engineers who work for Spiral spend significant time writing code, reviewing code, answering questions, writing documentation, and accepting sensible patches and pull requests from other contributors. LDK aims to build a sustainable open-source project that is welcoming to newcomers, beneficial to users, and ultimately not reliant on a single funding source. The development roadmap is transparent, and corporate priorities do not come first; users do.  

You Will

Contribute to LDK by writing and reviewing code, improving testing infrastructure, and assisting projects and companies that use LDK

Help add and maintain features such as the following:  

Language bindings, including Java/Kotlin, C#, JavaScript/WASM/browser extensions, and Swift

Support for splicing and dual-funded channels

Support for Taproot, including musig, PTLCs, multi-sig scripts, and custom scripts

Improve the performance, scalability, and robustness of LDK

BOLT 12, VSS, and anchor outputs

A server version of LDK

When you’re not doing all of that, you’ll improve bitcoin through passion projects of your choosing. Almost anything goes.

You Have

8+ years of professional experience

Hands-on experience with bitcoin and the Lightning Network

Experience programming with Rust, C, or C++

Ability to thrive in ambiguity and build creative solutions to complex problems

Appreciation for bitcoin

How to Apply

Include a link to your GitHub (if you’ve got one), any side projects you’ve got floating around that you think we should see, and some words that explain why you’re a fit for this position.  

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Candidates may submit up to 9 active applications within a 60-day period. Reapplications to the same role are accepted 90 days after a previous application has been reviewed.

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Block, Inc. (NYSE: XYZ) builds technology to increase access to the global economy. Each of our brands unlocks different aspects of the economy for more people.  Square  makes commerce and financial services accessible to sellers.  Cash App  is the easy way to spend, send, and store money.  Afterpay  is transforming the way customers manage their spending over time.  TIDAL  is a music platform that empowers artists to thrive as entrepreneurs.  Bitkey  is a simple self-custody wallet built for bitcoin.  Proto  is a suite of bitcoin mining products and services. Together, we’re helping build a financial system that is open to everyone.

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