Senior API Engineer

📋 Description

• • Architect and scale the API platform that powers $3.5 billion in annual freelancer transactions for 18 million registered users across 180 countries. You will own the design, delivery, and evolution of RESTful and GraphQL services that connect clients, freelancers, and internal product teams in real time.
• • Lead green-field initiatives to migrate monolithic endpoints to a cloud-native, event-driven microservice mesh on AWS (EKS, Lambda, Kinesis, DynamoDB) while maintaining 99.99 % uptime and sub-100 ms global latency. Your code will serve 10 k+ requests per second and directly influence conversion, search ranking, and payout reliability.
• • Establish company-wide API standards—authentication (OAuth 2.0, OIDC, SAML), rate-limiting, versioning, pagination, and backward compatibility—codified in OpenAPI 3.x, enforced by automatic linting, contract tests, and CI gates that block regressions before they reach production.
• • Champion a "developer-first" culture: publish interactive docs (Swagger, Redoc), SDKs (Node, Python, Go), and Postman collections that reduce third-party onboarding time from days to minutes; run monthly guild sessions, brown-bags, and hack-days to evangelize best practices across 50+ engineering teams.
• • Instrument end-to-end observability—distributed tracing (Jaeger), metrics (Prometheus, Grafana), and centralized logging (ELK)—to surface anomalies, forecast capacity, and drive data-backed performance tuning that cuts P99 latency by 30 % year over year.
• • Partner with product, security, and legal to launch public APIs for talent search, contract management, and time-tracking that external SaaS vendors embed into ATS, HRIS, and finance tools, creating new revenue streams and expanding Upwork’s ecosystem moat.
• • Mentor senior and staff engineers through architecture reviews, pair programming, and career road-mapping; foster an inclusive remote culture where every voice is heard and psychological safety fuels innovation.
• • Evaluate emerging tech—gRPC, GraphQL federation, serverless containers, WebAssembly edge workers—and run POCs that keep Upwork two steps ahead of marketplace demands without incurring tech debt.
• • Own on-call rotation for critical payment, identity, and messaging services; conduct blameless post-mortems that convert incidents into automated safeguards, reducing repeat issues by 40 %.
• • Translate business KPIs (GMV, NPS, churn) into engineering OKRs; ship features behind feature flags, run A/B tests, and iterate until metrics validate customer delight and revenue lift.