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- Tasks: Lead the development of a groundbreaking SaaS product using C# and AWS.
- Company: Join a fast-paced tech start-up with a focus on innovation.
- Benefits: Competitive pay, flexible work options, and opportunities for professional growth.
- Other info: Dynamic environment with a strong emphasis on quality engineering culture.
- Why this job: Make a real impact by architecting cutting-edge solutions in AI and serverless tech.
- Qualifications: Deep expertise in C#, .NET Core, and AWS serverless architecture required.
The predicted salary is between 80000 - 100000 £ per year.
Reporting to the Director of Engineering, this is a genuinely outstanding contract opportunity for a Senior C# Engineer to lead the development of a greenfield SaaS product. We’re looking for a deeply senior, technically hands-on engineer who thrives in complex problem spaces and fast-moving start-up & scale-up environments. You’ll need a genuinely Product Centric mindset and approach twinned with experience of AI-Native Engineering and Agentic Workflow.
Senior–Staff-level backend engineer with deep, current expertise in C# and .NET Core 8/9, capable of architecting and leading the design of distributed REST API microservices at scale. Authority in AWS serverless architecture; Lambda-first, with strong working knowledge of API Gateway, SQS, Step Functions, EventBridge and IAM, and a track record of shipping production workloads on this stack.
Hands-on experience with Claude Code (or similar) and advanced agentic workflows; multi-agent orchestration, context management, custom commands/skills and scaling AI-assisted delivery across a team. Expertise across Aurora RDS MySQL and DynamoDB; schema design, access patterns, indexing, query tuning, single-table vs multi-table trade-offs, and pragmatic thinking around consistency, scaling and cost.
Proven experience designing event-driven systems with SQS and adjacent AWS messaging; idempotency, retries, ordering, DLQs and operational robustness. Strong API design sensibility; versioning, documentation, throttling, backwards compatibility and a genuine obsession with developer experience.
A strong product brain; comfortable operating without a traditional Product Owner, partnering with BAs, making sensible trade-offs, prioritising ruthlessly and owning the solution through to delivery. Excellent communication skills and comfort with ad-hoc client interaction, able to ask the right questions, shape requirements and translate outcomes into shippable work.
A pragmatic, outcome-oriented mindset; comfortable with ambiguity, biased to shipping, and able to make sensible calls on scope, sequencing and technical debt.
What You’ll Own & Deliver:
- Architect, build and ship complex distributed services in C# and .NET Core 8/9, primarily serverless on AWS Lambda, setting the technical bar for the squad and delivering major feature sets end-to-end.
- Build resilient, event-driven systems using SQS and related AWS messaging primitives; idempotency, retries, DLQs, ordering and clean service boundaries.
- Leverage Claude Code, advanced agentic workflows and native AI engineering practices; orchestrating sub-agents, managing context, running parallel workstreams and embedding AI-native engineering patterns into everyday delivery.
- Own each feature’s solution end-to-end; partnering with BAs on high-level problems, then driving product thinking, scoping, trade-offs and delivery yourself.
- Design clean, well-versioned, well-documented APIs that other engineers love to consume; treating developer experience and contract stability as first-class concerns.
- Champion a high-quality engineering culture; test coverage, peer review, CI/CD discipline (GitHub Actions), IaC, secure coding, observability and performance.
Senior Staff Software Engineer - C#, Agentic Workflows & Native AI Engineering, .Net 8/9, AWS ([...] in London employer: Smart Sourcer
Contact Detail:
Smart Sourcer Recruiting Team
StudySmarter Expert Advice 🤫
We think this is how you could land Senior Staff Software Engineer - C#, Agentic Workflows & Native AI Engineering, .Net 8/9, AWS ([...] in London
✨Tip Number 1
Network like a pro! Reach out to your connections in the tech industry, especially those who work with C# and AWS. Attend meetups or online webinars to meet potential employers and get your name out there.
✨Tip Number 2
Show off your skills! Create a portfolio showcasing your projects, especially those involving .NET Core and serverless architecture. This will give you an edge and demonstrate your hands-on experience.
✨Tip Number 3
Prepare for interviews by brushing up on your technical knowledge. Be ready to discuss your experience with event-driven systems and API design. Practice coding challenges to keep your skills sharp!
✨Tip Number 4
Don’t forget to apply through our website! We’re always on the lookout for rockstars like you. Tailor your application to highlight your product-centric mindset and experience with AI-native engineering.
We think you need these skills to ace Senior Staff Software Engineer - C#, Agentic Workflows & Native AI Engineering, .Net 8/9, AWS ([...] in London
Some tips for your application 🫡
Show Off Your Skills: When you're writing your application, make sure to highlight your experience with C# and .NET Core 8/9. We want to see how you've tackled complex problems in the past, so don’t hold back on those juicy details!
Be Product Centric: We’re looking for someone with a product-centric mindset, so share examples of how you’ve partnered with BAs or made trade-offs in previous projects. This will show us that you can think beyond just coding and understand the bigger picture.
Talk About AWS Experience: Since AWS is a big part of what we do, make sure to mention your hands-on experience with serverless architecture and services like Lambda, SQS, and API Gateway. We love seeing candidates who can demonstrate their expertise in these areas!
Keep It Clear and Concise: While we appreciate detail, clarity is key! Make sure your application is well-structured and easy to read. Use bullet points if needed, and don’t forget to check for typos. A polished application shows us you care!
How to prepare for a job interview at Smart Sourcer
✨Know Your Tech Inside Out
Make sure you’re up to speed with C#, .NET Core 8/9, and AWS serverless architecture. Brush up on your knowledge of distributed REST API microservices and be ready to discuss your hands-on experience with tools like Lambda, SQS, and DynamoDB. The more specific examples you can provide, the better!
✨Show Off Your Product Mindset
This role requires a strong product-centric approach, so be prepared to talk about how you've partnered with BAs and made trade-offs in previous projects. Share instances where you’ve taken ownership of solutions from concept to delivery, highlighting your ability to prioritise effectively.
✨Demonstrate Your Communication Skills
Excellent communication is key for this position. Practice articulating complex technical concepts in simple terms, as you’ll need to interact with clients and team members alike. Think of examples where you’ve successfully shaped requirements or translated outcomes into actionable tasks.
✨Embrace Ambiguity and Problem-Solving
This role thrives in fast-moving environments, so be ready to discuss how you handle ambiguity and make decisions under pressure. Share stories that showcase your pragmatic, outcome-oriented mindset and how you’ve tackled complex problems in past projects.