Job Summary:
Anthropic is a public benefit corporation focused on creating reliable and interpretable AI systems. They are seeking a systems-oriented Software Engineer to enhance the performance and reliability of Claude Code and the JavaScript runtime, involving low-level programming and collaboration with researchers and product engineers.
Responsibilities:
• Design, build, and optimize core systems inside Bun and Claude Code—runtime internals, I/O paths, memory management, and the agent execution loop
• Drive down memory usage, latency, and startup time across Claude Code and the Bun runtime
• Dig into performance problems across the stack: profiling, tracing, and fixing issues anywhere from the kernel interface up through the JS engine to the agent layer
• Collaborate with researchers and product engineers to make sure model capabilities translate into a fast, reliable developer experience
• Contribute to the Bun runtime and toolkit, which underpins Claude Code, the Agent SDK, Cowork, and other internal Labs products
• Stay ahead of advancements in runtimes, compilers, and AI-assisted tooling—experimenting, measuring, and bringing the best ideas into our stack
Qualifications:
Required:
• Have a strong background in C and/or C++ and Rust (Zig also welcome)
• Have deep systems programming experience: syscalls, Linux internals, I/O (kqueue, epoll, io_uring), manual memory management, and performance engineering
• Have worked on language runtimes, virtual machines, compilers, or JS engines like JavaScriptCore or SpiderMonkey
• Have 5+ years of work experience
• Minimum education: Bachelor’s degree or an equivalent combination of education, training, and/or experience
• Required field of study: A field relevant to the role as demonstrated through coursework, training, or professional experience
• Minimum years of experience: Years of experience required will correlate with the internal job level requirements for the position
Company:
Anthropic is an artificial intelligence company that develops large language models and AI systems for business and research use. Founded in 2021, the company is headquartered in San Francisco, USA, with a team of 501-1000 employees. The company is currently Late Stage.