Senior Software Engineer - API Infrastructure

Senior Software Engineer — API Infrastructure Location: San Francisco, CA — Onsite, five days per week Employment Type: Full-Time, Direct Hire Compensation: $195,000–$225,000 base salary, plus equity and benefits Note: No C2C arrangements will be considered. Any attempt to use personal or household contact information for solicitation, candidate submission, or vendor outreach is strictly prohibited and will be reported to LinkedIn. Our client is a well-funded, growth-stage technology company building sophisticated enterprise data and analytics products. The engineering organization is small, highly technical, and focused on solving complex problems involving distributed systems, large-scale data processing, and production reliability. They are seeking a hands-on Senior Software Engineer — API Infrastructure to build and operate the foundational systems supporting a rapidly growing data platform. You will own the service layers, API gateways, worker fleets, queues, and orchestration systems that keep the platform fast, available, observable, and securely multi-tenant under real customer load. This is a senior individual contributor position for an engineer who thinks deeply about scalability, distributed-system behavior, production operations, and failure modes. You will be expected to build systems, operate them in production, and improve them as customer traffic and processing workloads increase. What You’ll Do Design, build, and operate API services, gateways, and distributed worker fleets.Develop asynchronous job-processing and workflow-orchestration systems for long-running data workloads.Build with message queues and event-streaming technologies such as NATS, Kafka, RabbitMQ, or similar platforms.Design systems for autoscaling, rate limiting, backpressure, retries, idempotency, graceful degradation, and failure recovery.Establish service-level objectives and improve reliability across a multi-tenant platform.Implement secure authentication, authorization, and tenant isolation using OIDC, OAuth, Keycloak, or comparable technologies.Develop tracing, logging, metrics, and monitoring that allow engineers to understand requests from end to end.Optimize PostgreSQL queries, indexing, connection management, and concurrency performance.Partner with API, SDK, product, data, and infrastructure engineers to create stable, scalable platform interfaces.Troubleshoot complex production issues across applications, databases, queues, containers, and infrastructure.Participate in operational support and incident response for the systems you build.Document system architecture, operational procedures, and important technical decisions. Must-Have Qualifications 5+ years of professional software engineering experience building production systems.Strong production-level Python experience, including asynchronous programming, type hints, and maintainable backend service development.Experience designing and operating distributed backend systems at scale.Strong understanding of stateless services, idempotency, retries, concurrency, fault tolerance, and distributed-system failure modes.Hands-on experience with message queues or event-streaming technologies such as NATS, Kafka, RabbitMQ, or similar systems.Experience with workflow orchestration using Temporal, Airflow, Celery, or a comparable platform.Strong API infrastructure experience, including gateways, load balancing, rate limiting, versioning, and backward compatibility.Deep PostgreSQL experience, including query optimization, indexing, transactions, and connection management.Experience building or supporting secure multi-tenant systems.Knowledge of modern authentication and authorization standards such as OIDC, OAuth, or Keycloak.Strong Linux, Docker, Kubernetes, and CI/CD experience.Experience owning production systems, including monitoring, troubleshooting, incident response, and long-term reliability improvements.Strong written communication and technical documentation skills.Ability to work effectively in a fast-moving environment with evolving priorities and broad technical ownership. Nice-to-Have Qualifications Experience writing performance-sensitive software in Rust, C++, Go, or another systems-oriented language.Experience supporting GPU-backed workloads, distributed scheduling, or high-performance computing environments.Familiarity with large-scale compute infrastructure.SRE, platform engineering, or infrastructure engineering experience.Experience with secrets management, service identity, or zero-trust access controls.Experience building APIs, SDK infrastructure, internal platforms, or developer tooling.Previous experience in a high-growth startup or similarly dynamic engineering environment. What Success Looks Like You may be a strong fit if you: Design systems for future growth rather than only current traffic.Think proactively about failure modes and recovery paths.Build infrastructure that is observable, debuggable, and maintainable.Take responsibility for both shipping software and operating it.Make sound technical decisions with incomplete information.Move quickly without compromising security, reliability, or engineering quality.Use AI-assisted development tools thoughtfully while maintaining strong independent engineering judgment.Thrive in a low-ego environment where priorities and responsibilities may evolve. Why This Opportunity Own critical infrastructure supporting a growing enterprise platform.Solve complex problems involving distributed systems, asynchronous workloads, multi-tenancy, and production reliability.Work with modern data, API, container, and large-scale computing technologies.Join a small, highly technical engineering team.Have meaningful influence over architecture, tooling, and engineering practices.Receive a competitive base salary of $195,000–$225,000, plus equity and comprehensive benefits. Work Authorization: Candidates must be currently authorized to work in the United States. This position is not eligible for new or future employer-sponsored work authorization.