Senior Backend Engineer (Golang/Python/NodeJS)

1. CDN Optimization & RoutingBuild dynamic routing services across in-house & third-party CDNs (BytePlus, Gcore, etc.) based on real-time conditions (ISP, bandwidth, cost, QoS).Implement feedback loops using QoE metrics for automatic CDN selection.2. Experimentation & Config PlatformDevelop APIs/services for real-time A/B testing, feature flagging, and config-based behavior without redeployments.Collaborate with data engineers to design pipelines and stores for variant analysis.3. Engagement PlatformDesign backend systems for omnichannel messaging (push, in-app, email) using real-time user segmentation.Integrate with messaging providers and build routing/logging systems for reliability.4. Transcoding System IntegrationBuild control panels for configuring backend services, transcoding profiles, and routing rules.Ensure role-based access, audit logging, and fail-safe designs.5. Core Engineering PracticesDesign clean APIs, asynchronous workers, and scalable microservices with observability (metrics/logs/traces).Write automated tests (unit/integration/load), CI pipelines, and infrastructure-as-code when required.