Senior .NET AI Backend Lead (Azure, RAG & LLM)

Spyrosoft Ltd; Polska; Hybrid; PLN 180,000 - 240,000; Full time

Job summary

Spyrosoft Ltd is seeking a Senior .NET Backend Developer to lead AI capabilities in a SaaS platform delivering procedures and practice guidance to public sector and social care organisations in the UK.

You will shape the AI architecture, ship production-grade RAG and AI search features on Azure, and integrate with Squidex for content management, ensuring quality, safety and compliance in a regulated domain.

Qualifications

• 7+ years of professional C#/.NET development, including recent .NET (8 or later), ASP.NET Core and REST API design.
• Hands-on experience shipping LLM-based features to production (ideally RAG or AI search).
• Knowledge of embeddings, vector search, chunking strategies and prompt design.
• Strong Azure experience, including Azure OpenAI or Azure AI Search, plus core services (App Service/AKS, Functions, Storage, Key Vault).
• Experience using AI tools to accelerate development (Claude Code, Codex).
• Automated testing, CI/CD, observability and infrastructure as code (Bicep or Terraform).
• Data protection and security when handling sensitive information.
• Ability to explain technical trade-offs to product/compliance teams.
• English level C1 or higher.

Responsibilities

• Agreeing the architecture and roadmap for AI capabilities with the Head of Product and Engineering Manager.
• Leading design reviews, code reviews and technical decisions for AI work, documented as lightweight decision records.
• Mentoring and upskilling C# developers in AI engineering practice, prompt design and evaluation.
• Making build-versus-buy recommendations on models, services and tooling with cost and risk clearly out.
• Building RAG for grounded search with citations to source material.
• Implementing hybrid search and relevance tuning with per-authority content scoping.
• Delivering AI features such as summarisation and AI-assisted content authoring for editors.
• Integrating with Squidex or a headless CMS and building ingestion pipelines to sync indexes.
• Designing and running AI workloads on Azure with IaC and CI/CD pipelines.
• Monitoring latency, quality and cost with Application Insights and Azure Monitor.
• Building evaluation sets and automated checks for answer accuracy and regressions.
• Guardrails to prevent hallucination, prompt injection and cross-tenant leakage.
• Ensuring GDPR compliance, data residency and WCAG 2.2 AA accessibility.
• Beta to GA gates with evidence; keep runbooks and decisions current.

Skills

C# / .NET

ASP.NET Core

REST API design

LLM integration

Azure OpenAI / Azure AI Search

CI/CD

IaC (Bicep or Terraform)

Data protection & security

English (C1+)

Leadership / mentoring

Tools

Azure OpenAI

Azure AI Search

Squidex

Semantic Kernel

Codex

Claude Code

Terraform

Bicep

Job description

Spyrosoft Ltd is seeking a Senior .NET Backend Developer to lead AI capabilities in a SaaS platform delivering procedures and practice guidance to public sector and social care organisations in the UK.

You will shape the AI architecture, ship production-grade RAG and AI search features on Azure, and integrate with Squidex for content management, ensuring quality, safety and compliance in a regulated domain.