Backend API Developer

Job Description: Type of Requisition: Regular Clearance Level Must Currently Possess: None Clearance Level Must Be Able To Obtain: None Public Trust/Other Required: NACI (T1) Job Family: Data Science and Data Engineering Skills: Job Qualifications: Back-End Development, Building Operations, Cloud Delivery, Design Development, Network Gateway Certifications: None Experience: 8 + years of related experience US Citizenship Required: Yes Job Description: Position Summary The Backend API Developer builds and operates the service layer behind an operator application in a cyber command center supporting national cyber defense across Critical Infrastructure and government partners. Responsibilities focus on low‑latency service delivery, correctness under load, and strict entitlement enforcement. Key Responsibilities Service Design & Development • Build and operate independently deployable services behind the application. • Maintain interface contracts, versioning, and backward compatibility. • Implement consistent request handling, validation, errors, authentication, and authorization. • Create automated tests for service behavior and contract compliance. Upstream Integration & View State • Integrate with upstream services via REST and streaming interfaces. • Maintain accurate, consistent view state and ensure clients connecting mid‑stream receive a complete picture. • Coordinate payload and interface changes with upstream service owners. Real-Time Delivery • Deliver updates using server-sent events and WebSocket streams. • Manage connection lifecycle, authentication, backpressure, reconnection, and catch‑up. • Sustain large numbers of concurrent long‑lived connections without degradation. Authorization & Content Filtering • Enforce role and attribute-based authorization server‑side. • Implement content filtering so users receive only authorized data. • Test entitlement enforcement and maintain audit logs of all deliveries. Event-Triggered Services • Build and operate event-triggered functions for routing, downstream actions, and notifications. • Integrate with managed messaging services. • Ensure triggered actions are idempotent, observable, and safely retried. Performance, Reliability & Operations • Design and validate services for low-latency, high-throughput use. • Instrument services for monitoring, diagnosis, and production incident response. • Deploy through established pipelines into containerized environments. • Maintain required training and certifications; report certification status monthly. Collaboration • Collaborate with front-end engineers on service contracts. • Work with platform teams on configuration, scaling, secrets, and deployment. • Participate in sprint planning, demos, and reviews. Required Qualifications • Experience building and operating production service interfaces at scale. • Experience integrating with upstream services and maintaining derived state. • Knowledge of push/streaming delivery, connection lifecycle, and backpressure. • Experience with server-side authorization models. • Experience with containerized deployment and cloud environments. • Experience instrumenting services and supporting production incidents. • BS in computer science or engineering and 8+ years relevant experience (or equivalent). • Public Trust eligibility and U.S. citizenship. • On-site work in the Washington, D.C. metro area (not remote or hybrid). Preferred Qualifications • Experience with streaming platforms (Kafka, MSK, Event Hubs). • Experience with API gateways or service meshes. • Experience with serverless functions (Lambda, Azure Functions). • Experience supporting latency‑sensitive operational systems. • Experience delivering software in regulated environments. • Current cloud developer/associate certification. GDIT Is Your Place At GDIT, the mission is our purpose, and our people are at the center of everything we do. • Growth: AI-powered career tool that identifies caree