Senior AI Backend Engineer AWS / Node.js / TypeScript
Serve First CX Limited
- Milton Keynes
- Permanent
- Full-time
Team: Engineers across UK, US, India, Philippines
Reports to: CTO (US)
Works closely with: Head of Engineering (India)Why Serve FirstWere a scrappy, well-funded (£4.5m seed closed) AI startup turning raw customer feedback into real-time insight for businesses that care about CX.
Our 2025 roadmap is ambitious:Break apart our Node.js monolith into microservicesDouble our AI-driven workflowsHarden infra for 100× trafficEveryone ships. Everyone is on-call. Bureaucracy is nil. Velocity is high.What Youll DoBreak up the monolith
Define service boundaries and lead the transition to a microservices architecture. Implement REST + SQS communication, containerized on ECS Fargate. Design services that scale, not snowball.Own AI workflow integration
Build and orchestrate AI workflows using OpenAI/Claude APIs today and frameworks like LangChain or similar. Design composable, multi-model pipelines (prompt orchestration, vector DBs, caching, telemetry). Lead the shift toward Bedrock/RAG-native infrastructure.Build and scale AI infra
Stand up inference/workflow infra on AWS (Bedrock, SageMaker, or containerized flows). Make AI systems observable, secure, and cost-efficient. You wont be training models from scratch, but youll architect the systems to support them if/when we need to.Architect the AI platform
Were not just wrapping GPT. Were building infrastructure for experimentation, scale, and optional self-hosting. Define orchestration vs. inference boundaries, expose tracing and prompt history, and keep iteration sane.Champion testing and correctness
Enforce robust testing strategies (unit, integration, load). Design testable systems with clear mocks, interface contracts, and fast CI.Estimate, scope, deliver
Break complex features into milestones, identify hidden risks, and communicate trade-offs clearly. Youll shape specs as much as you implement them.Make it observable
Build first-class telemetry: structured logs, metrics, traces, alerts. Make LLM behavior debuggable and traceable from token usage to prompt mutation.Think security first
Handle sensitive customer data with care: PII handling, IAM design, secrets management, rate limiting, GDPR readiness.Ship backend code
Work in Node.js/TypeScript with MongoDB (Mongoose), Redis, and job schedulers (cron/EventBridge).Keep infra flexible
AWS-first today, modular Terraform for future cloud (GCP) support.Mentor & raise the bar
Lead reviews, mentor engineers, and reinforce best practices without slowing velocity. Know when to lean on AI tools and when not to.Must-Haves8+ years backend engineering; deep experience building distributed systems on AWS with Node.js/TypeScriptStrong system design skills, especially event-driven/autoscaling architecturesProduction LLM workflow experience (OpenAI, Claude, etc.): you know context windows, token limits, caching, and cost trade-offsWorkflow orchestration: experience with LangChain, agentic frameworks, or equivalent workflow automation stacksInfra-aware mindset: youve deployed and scaled AI workflows/inference via Bedrock, SageMaker, or containersMongoDB & Redis tuning/debugging chopsTerraform & Docker fluencyTesting mindset with CI/CD experienceClear async communicator (writing, docs, code)Security & compliance awareness (GDPR/SOC2 basics)Proven ability to scope, build, and deliver complex backend featuresNice-to-HavesBackground in CX, survey, or analytics SaaSBedrock, LangChain, or RAG-native infra exposureLLMOps experience (prompt versioning, feedback loops, telemetry)GCP infra experience / portabilityReact familiarity or empathy for frontend engineersIncident response and blameless postmortemsWhat We OfferCompetitive salary (band shared at offer stage)Standard UK pension20 days holiday + public holidaysGenerous hardware/kit budgetHigh autonomy, massive scopePersonal and professional development budgetAdditional Perks
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