Senior Full-Stack Engineer (AI-Enhanced SaaS)

We build complex, AI-powered SaaS products that solve real problems in education, healthcare, and construction. Our customers rely on us for secure, dependable software that integrates cleanly with their ecosystem and scales with their growth. immersive.co.uk

We’re looking for an experienced engineer who loves owning end-to-end solutions, someone who can move comfortably from product thinking to elegant UI, robust APIs, and cloud-native delivery.

If you thrive in a pragmatic, high-trust environment and want to push the boundaries of what teams can achieve with AI, you’ll feel at home here.

What you’ll do

• Ship product end-to-end: Design, build, test, and operate features across the stack, from React UI to API to infrastructure.

• Integrate intelligently: Orchestrate third-party APIs and services smoothly.

• Build for scale and safety: Apply sound architecture, strong security, and thoughtful data models.

• Lean into AI: Connect to and compose LLMs and multimodal models, design prompts, and evaluate outputs with guardrails.

• Own quality: Champion testing, observability, and automated CI/CD so we ship with confidence.

• Collaborate deeply: Work with product, design, and domain experts to translate nuanced requirements into simple, usable software.

• Continuously improve: Leave the codebase, the docs, and the developer experience better than you found them.

Note: UK Residents only please.

What you’ll bring

Core technical skills

• TypeScript/JavaScript and React (hooks, state management, component architecture).

• Solid back-end experience (Node.js); familiarity with Python for AI integration is a plus.

• Proficiency with software architecture patterns (SOA, microservices).

• Confident integrating external APIs, webhooks, and third-party services.

• Unit, integration, and E2E testing.

• SaaS mechanics: subscriptions, licensing, payments/billing (bonus).

• Security foundations: RBAC, least-privilege, auditability (bonus).

AI & ML integration

• Connecting to LLM/AI APIs and composing them reliably.

• Prompt design and evaluation for text, image, and multimodal tasks.

• Understanding of multimodal patterns (speech, text, vision) and when to use them.

• Exposure to orchestration frameworks (e.g. LangChain), agentic patterns, MCP etc are a bonus.

Cloud, infra & DevOps

• Strong AWS experience (e.g., Lambda, ECS, S3, CloudFront).

• Containers: Docker and Kubernetes for repeatable dev and scalable deploys.

• CI/CD: GitHub Actions (or similar)

• IaC with Terraform or CDK is a plus.

Data & analytics

• Experience with product analytics and performance telemetry.

• Experience building analytics pipelines/dashboards (nice to have).

Professional experience

• Track record across the full lifecycle: discover → design → build → test → deploy → operate.

• Comfortable juggling multiple products/modules and collaborating in Agile teams.

• Strong ownership, excellent communication, and a product-centric mindset.

Nice to have

• C# for integrations or internal tools.

• Unity or Three.js for 3D/avatars and richer interaction.

• LLM fine-tuning, retrieval-augmented generation, or prompt optimization.

• EdTech know-how (SCORM, LMS, LTI) or domain experience in healthcare/construction.

• Voice & realtime: WebRTC/WebSocket; ASR/TTS (Whisper, Deepgram, Azure Cognitive Services, etc.).

• Compliance fluency (e.g., GDPR, HIPAA) and working in regulated contexts.
  

How we work

We’re a friendly, outcome-focused team that values clarity, kindness, and momentum. You’ll find:

• High trust and clear ownership, no micromanagement.

• Practical engineering, we choose the simplest thing that works, then iterate.

• AI-first mindset, we use AI to accelerate discovery, coding, testing, and support (with human judgement and safeguards).

• Flexible, hybrid working with time for deep focus and time for collaboration.

Our tech environment

• Frontend: React, TypeScript, JavaScript, MUI.

• Backend: Node.js, TypeORM, REST.

• AI: OpenAI/Anthropic. LangChain. RAG.

• Infra: AWS (Lambda/ECS/S3/CloudFront), Docker, GitHub Actions, Terraform.

What you’ll get

·       Competitive compensation with performance-linked reviews.

·       Flexible/hybrid work environment and supportive time-off policy.

·       Support for personal development & training.

·       Diverse, challenging and interesting projects and products to get your teeth into.

The hiring process

1. Intro chat (30 mins), mutual fit, your interests, and role context.

2. Short project (<=3 hours) – build a simple app to a spec. No vibe-coding!

3. Talk us through it (1-1.5 hours) – share your methodology, thought processes and analysis.

Apply with your CV/LinkedIn and a short note about a project you’re proud of. If your experience is close but not a perfect match, we’d still love to hear from you, potential beats perfection.

We’re an equal-opportunity employer. We celebrate diversity and are committed to creating an inclusive environment for all.