Backend Software Engineer, SDK

About LaunchDarkly Engineering LaunchDarkly helps engineering organizations ship software and AI with speed, safety, and control. Our platform gives teams the confidence to release gradually, target experiences to the right audiences, learn through experimentation, understand what is happening in production, and respond quickly when risk appears. Our engineers build the systems, services, SDKs, developer tools, cloud infrastructure, and product experiences that make this possible. The work spans high-scale distributed systems, reliable data and event pipelines, intuitive enterprise workflows, and AI-powered capabilities that help teams manage the next generation of software delivery. LaunchDarkly’s SDKs are used in systems that perform trillions of feature flag evaluations each day, giving our engineering work a direct connection to the reliability and customer experience of software around the world. As the company grows, we are expanding beyond traditional feature management into experimentation, observability, and AgentControl—helping customers control more of the software and AI lifecycle. That creates an unusually broad set of technical challenges, visible customer impact, and room for engineers to shape what comes next. We believe in the power of teams. We work with humility, openness, curiosity, and care; we value clear communication, thoughtful technical judgment, inclusive collaboration, and a strong sense of ownership. We encourage people to apply even when they do not meet every qualification listed below. We are interested in the experience, perspective, and potential you would bring to the role. About the Job As a Software Engineer on LaunchDarkly’s SDK team, you will build the primary touchpoint that our customers interact with on a daily basis. You’ll work with multiple technologies across our 35+ SDKs while enabling customers of all kinds to feature flag their code. When working on our SDKs, you’d be contributing to much more than thin client wrappers. Our SDKs are feature-rich agents with strong emphases on performance, concurrency, and resiliency -- all while following idiomatic practices for their tech stack. LaunchDarkly serves trillions of feature flags daily to customers all around the globe, and every flag is handled by our SDKs. This team has a major impact not only on our company, but on our customers (and their customers). We are growing fast and we need your help writing the next chapter in our story. Responsibilities: • Contribute to development for SDKs in supported platforms : • Implement new features and improvements to meet customer performance and resiliency requirements • Keep up to date with the latest development practices • Collaborate with our engineering and product teams to drive the implementation and release of major features • Actively maintain our open-source repositories • Identify areas of improvement and advocate for best practices • Have an active voice in shaping both technology and product decisions Basic Qualifications: • Demonstrable experience building libraries and packages used by other developers • Polyglot background with an ability to context switch between languages quickly • 5+ years experience with at least two of the following: .NET/Go/Ruby/Python/NodeJS/Java • Experience with the following is a plus: • C++/Erlang/Haskell/Lua • AI SDKs • Observability SDKs • Mobile development • Strong computer science fundamentals • Committed to working in a communicative, collaborative environment • Self‐starter and problem solver, willing to solve difficult problems and work independently when necessary • Strong testing background: experience building unit, integration, load tests, and benchmarks • Experience writing production-ready code with emphasis on