Back End Developer (United Kingdom)

Backend Engineer (AWS-based SaaS Platform, LLM-powered)*

Project: 4- to 6-week build sprint

Location: Remote (2–3 h overlap with UK time)

Fee: Fixed-price USD $4,000-$6,000

About Us

We’re a boutique consultancy spinning up an AI-enabled SaaS product. Our AWS backbone—multi-AZ VPC, ECS Fargate, ALB, Terraform IaC, logging/monitoring, IAM hardening, etc. is already in place. Your brief is to layer business logic, API endpoints and a small admin UI on top of this platform, integrating an LLM-driven scoring pipeline plus a few external APIs.

What You’ll Tackle

*Backend feature work*

• Design and ship REST or GraphQL endpoints.

• Build multi-tenant data models and role-based workflows.

• Trigger emails and webhooks for status changes.

*AI / Retrieval-Augmented Generation*

• Wire existing prompts to an LLM API (OpenAI-compatible today, private model later).

• Store embeddings in a vector store and perform RAG look-ups.

• Surface “explanation” JSON for every model decision.

*Cloud hand-offs*

• Deploy new services into the existing Terraform / ECS stack—extend, don’t rewrite.

• Add CloudWatch alarms, log routes and parameter-store secrets where needed.

*Quality & Ops*

• Write unit and integration tests and set up a lightweight CI pipeline.

• Provide concise hand-over docs and 30 days of post-launch bug-fix cover.

Must-Have Skills

• Pro in *Python (FastAPI)* or *Node.js (TypeScript / Nest)*—ready to justify your pick.

• Experience extending an *AWS stack (Terraform, ECS Fargate, ALB, Secrets Manager, KMS)*.

• Hands-on with *LLM APIs* and at least one *vector database* (Pinecone, Weaviate, OpenSearch, etc.).

• Multi-tenant data design with GDPR awareness.

• CI/CD and automated-testing mindset.

Nice-to-Haves

• *Solution-architect background*—ability to map future services and scaling paths.

• Prior LLM fine-tuning or custom-model training.

• Chrome-extension data capture.

• Transactional-email tooling (SES, Postmark, Mailgun).

Following this sprint project there will be an additional 2-3 sprint projects of similar size to follow.