Backend Software Engineer

Backend Software Engineer - Data Infrastructure Company: $75M+ funded — AI Data Infrastructure Location: On-site, San Francisco, CA (5 days/week in-office) Salary: $175K–$225K + competitive equity Sponsorship: open to visa transfers (OPT, H1B) We're hiring several Backend Software Engineers for a fast-growing, well-funded startup building the data layer for audio AI. The founding team are former engineers and operators from leading AI infrastructure companies, and in under a year the company has landed a majority of the largest AI labs and enterprise tech companies as customers. This isn't a role where you own one narrow slice of the stack. You'll be building the pipelines, systems, and infrastructure that power how the world's leading AI labs process and make sense of speech and audio data, at a company already processing terabytes of it daily. The problem you'd help solve: High-quality training data is the current bottleneck for audio AI. Text has largely been solved; audio hasn't. Emotion, tone, pace, and accent don't translate cleanly, which makes this a fundamentally harder data problem than the last generation of labeling companies dealt with. This team is lean, moves fast, and already has more enterprise demand than it can serve. You'd work across three products, backend systems, data pipelines, and researcher-facing tooling, architecting APIs and infrastructure that thousands of users touch daily, with real ownership over how it gets built. You'll likely be a fit if you have: 2-6 years of backend software engineering experienceProficiency in Python and TypeScript (both are used in technical interviews)Experience at high-growth, VC-backed startups, not exclusively large/legacy companiesDemonstrated ownership of zero-to-one projects with measurable business impactExperience building scalable backend systems or data processing pipelines in productionA CS degree from a strong program (top ~50 US or equivalent, e.g. Waterloo) Nice to have: Familiarity with Node.js, PostgreSQL, or AWSDomain experience in audio, ML, or data infrastructureExposure to WebRTC, FFmpeg, or real-time data pipelines What you won't find here: This role won't suit you if you've spent your career exclusively at large, slow-moving companies and want a well-defined spec handed to you. You'll be shaping infrastructure decisions the rest of the team builds on as the company scales. Sponsorship: open to visa transfers (e.g. OPT, H1B). Candidates must be able to work on-site in San Francisco 5 days/week. Seniority Level: Mid-Senior level Industry: Technology, Information and InternetData Infrastructure and AnalyticsArtificial Intelligence Employment Type: Full-time Skills: PythonTypeScriptNode.jsPostgreSQLAWStRPCWebRTCFFmpegData PipelinesBackend Systems Architecture