Founding Software Engineer
About the OpportunityOur client is an early-stage, well-funded startup building the infrastructure that lets AI agents communicate and operate in the real world — think of it as giving autonomous software its own inbox, identity, and the ability to safely send and receive real-world communications at scale. Backed by a group of respected technology investors and operators, the company has seen rapid, sustained growth in both users and revenue since its public launch earlier this year, and is scaling its small, technically elite founding engineering team to keep pace.What You'll DoCore ownership: Design and build the APIs and backend infrastructure that power how AI agents communicate, authenticate, and operate — this is the heart of the productEnd-to-end projects: Own initiatives from scoping requirements through system design to production launch, on efforts like protocol integrations and usage-based pricing systemsFull-stack when needed: Work across the stack as required (roughly 80% backend, 20% frontend or adjacent), touching distributed systems, databases, and developer toolingBring your own ideas: Proactively identify and pitch growth, product, or infrastructure improvements rather than only executing assigned ticketsCustomer-facing moments: Serve as a frontline resource for customer feedback, occasionally supporting enterprise customers through custom deploymentsDocumentation and craft: Write clear, maintainable code and strong technical documentation for infrastructure that processes a very high daily volume of real-time trafficWhat You BringExperience level: 0-5 years of full-stack or backend engineering experience; strong new grads with excellent academic performance and internships are welcome to applyCompany background: Experience at a well-known, VC-backed startup (Series A or later) or a major technology companyOwnership track record: A history of shipping and owning products or features end-to-end, from concept (0) to live production (1)Production experience: Experience building and scaling production systems that handle real user loadBonus experience: Exposure to email, messaging, or other protocol-heavy systems is a strong plusEducation: A degree in computer science or a related technical field is preferred, particularly for candidates earlier in their careersCore language: Strong proficiency in TypeScript or another modern backend frameworkBackend fundamentals: Solid grounding in REST API design, system design, and server-side architectureInfrastructure exposure: Familiarity with cloud infrastructure, distributed systems, or developer tooling; experience applying these to AI/LLM or autonomous-agent use cases is a bonusHigh agency: You proactively surface ideas and drive execution without waiting for scope to be handed to youCommunication: A clear, direct style, especially around tradeoffs, blockers, and technical decisions in a fast-moving environmentWhy JoinGreenfield ownership: Most projects here start at zero — you scope them, build them, and ship themGeneralist-friendly: The core product is infrastructure- and API-heavy, but you're encouraged to follow your curiosity into growth, product, or forward-deployed engineering workCompetitive compensation: $150,000-$200,000 base salary (flexible above this range for exceptional candidates) plus 0.5%-1% equityEveryday perks: A daily fitness membership, plus breakfast, lunch, and dinner coveredStrong team, real momentum: A small, technically strong founding team backed by well-regarded early-stage investors, growing quickly and hiring for multiple openings on this team Location & LogisticsOn-site role: This position is based on-site in San Francisco, CA, five days a week