Software Library Engineer (C++)

Summary

Join Blockstream, a leading Bitcoin technology company, as a Software Library Engineer to lead the development and maintenance of the Green Development Kit (GDK), a crucial software development kit for their Bitcoin wallet apps. This role involves developing and maintaining the Core SDK (written in C/C++), integrating it with Rust modules, language wrappers, build systems, testing frameworks, and documentation. You will be responsible for debugging complex issues, enhancing performance, and ensuring seamless integration with Blockstream wallets and third-party users. The ideal candidate will possess strong technical skills in C++ and a collaborative mindset to ensure the project remains robust, efficient, and developer-friendly.

Requirements

• Experience : 5+ years of software development experience, with at least 3 years focused on C++ in complex, multi-component systems
• Experience with cross-language integration (e.g., C++ with Rust, Python, Java, or Swift)
• Familiarity with CMake, Docker, and CI/CD workflows
• Technical Skills : Expert-level proficiency in C++ (modern standards, e.g., C++17/20)
• Strong understanding of systems programming, memory management, and performance optimization
• Knowledge of testing frameworks and writing robust unit/integration tests
• Soft Skills : Exceptional problem-solving and debugging capabilities
• Clear communication skills for documenting code and collaborating with distributed teams
• Ability to manage priorities and lead technical initiatives

Responsibilities

• Core SDK Development & Wrapper Integration (C/C++) Lead the development, maintenance and testing of the Core SDK, written in C/C++
• Debug complex issues, enhance performance, and ensure seamless integration with the Blockstream wallets and third party users
• Build System Contributions Maintain and enhance CMake build files, build scripts, and Docker configurations to support C++ development and cross-component builds
• Resolve build-related issues and optimize for multiple platforms
• Publish regular releases incorporating new features, fixes and performance improvements
• Testing & Continuous Integration (CI) Develop and maintain C++-focused test cases within the testing suite
• Work with CI pipelines to validate Core SDK changes and their impact on downstream components
• Documentation Document C++ APIs, core functionality, and integration points for contributors and end-users
• Collaborate with the team to keep project-wide documentation current and accessible
• Collaboration with Mobile App Developers Partner with mobile app developers, the primary users of the GDK library, to understand their needs and ensure the Core SDK meets requirements for iOS (Swift) and Android (Kotlin) environments
• Provide technical support and guidance to app developers integrating the library into their applications

Preferred Qualifications

• Experience with Rust and/or Python
• Background in bitcoin or cryptocurrency development
• Knowledge of cryptography
• Familiarity with SWIG or similar tools for language bindings
• Contributions to open-source projects on GitHub, especially in C++ ecosystems
• Bachelor’s degree in Computer Science, Engineering, or a related field (or equivalent experience)