Principal Engineer, Spark (Bitcoin/ETH/L2)

Lightspark is building open payments for the Internet—always-on payment solutions powered by Bitcoin, the only open, neutral network for moving value. With enterprise tools like Connect, UMA, and Spark, businesses can send and receive money instantly, securely, and at a fraction of the cost, anytime, anywhere. Lightspark is headquartered in Los Angeles, California, but serves the world.

Spark (spark.money) is a Bitcoin-native Layer 2 for payments and settlement that delivers the fastest, simplest, and cheapest rails in crypto while enabling native, scalable, self-custodial assets like BTC and stablecoins. This is a rare opportunity to join a brand-new L2 for Bitcoin, work on the infrastructure behind our fastest-growing product with top-tier customers, and help build the future of scalable Bitcoin payments.

The Spark Operator (SO) team is at the core of our protocol, responsible for writing the code that serves as the backbone of the Spark network. We’re seeking a highly adaptable, hands-on Principal Engineer who can work across domains to define architecture from the ground up, dive into unfamiliar territory, and design, build, and scale a next-generation open payments network. You’ll work directly with our CTO and early engineering team to influence protocol evolution and deliver the infrastructure for a Bitcoin Layer 2 that is reshaping global payments.

WHAT YOU’LL BE DOING:

• Design, build, and scale distributed backend services that power Spark
• Own system architecture for highly available, low-latency services processing real-time Bitcoin transactions globally
• Extend and enhance protocol capabilities to support new markets, assets, and payment flows (including BTC and stablecoins)
• Write high-quality, production-grade code across multiple domains and layers of the stack (core protocol logic, orchestration, data infra, monitoring)
• Analyze complex distributed behaviors in adversarial environments and design resilient systems that can withstand them
• Work directly with leadership to influence long-term protocol direction and technical strategy
• Mentor engineers, raising the bar for technical depth and execution
• Adapt quickly to new challenges, whether designing new systems, debugging complex distributed behaviors, or scaling production infrastructure under load

WHAT WE’RE LOOKING FOR:

• 10+ years of engineering experience, with significant contributions to Bitcoin, Ethereum, L2s, or the stablecoin ecosystem
• Deep experience building adversarial distributed systems and protocol-level infrastructure
• A strong systems thinker who understands cryptography fundamentals (without needing to be a cryptographer) and how crypto-native communities operate
• Proven ability to independently analyze complex systems, identify weaknesses, and implement improvements
• Strong track record of technical leadership: driving architecture decisions, shaping roadmaps, and shipping mission-critical systems
• Comfortable operating across different languages, frameworks, and problem domains; primary stack includes Go, with additional work in Python, Rust, C++, and Kotlin
• Hands-on experience with modern infrastructure tooling (Docker, Kubernetes, AWS, monitoring/observability stacks)
• Pragmatic problem-solver with a data-driven mindset and strong debugging chops
• CS degree or equivalent is welcome but not required—we value deep skill and proven contributions over credentials

Lightspark is on a mission to build an open payment protocol for the Internet at scale and therefore we’re committed to creating a more inclusive and diverse workplace to reflect the customers we serve. We welcome interest from individuals of all backgrounds and levels of experience who share our mission. We do not discriminate based on race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, disability status, or other applicable legally protected characteristics. 

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