> Markdown version of [/jobs/ext/3525537-senior-c-engineer-typescript-lambda-api-gateway-sqs-sns](https://www.wearedevelopers.com/jobs/ext/3525537-senior-c-engineer-typescript-lambda-api-gateway-sqs-sns). Every page supports `.md` or `Accept: text/markdown`. Links point to the HTML versions so they work for humans too. Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Senior C# Engineer - Typescript, Lambda, API Gateway, SQS, SNS - **Company:** Smart Sourcer Limited - **Location:** London, UK (Remote available) - **Experience:** Expert - **Salary:** £182,000.0 - £208,000.0 - **Contract:** Temporary contract - **Skills:** .NET Framework, Application Programming Interfaces (APIs), Artificial Intelligence, Amazon Web Services, Data Analysis, C Sharp (Programming Language), Continuous Integration, Amazon DynamoDB, Event-Driven Programming, Github, Identity and Access Management, MySQL, OAuth, OpenID, Query Optimization, Secure Coding, Service Design, Amazon Simple Notification Service (SNS), System Testing, Systems Integration, TypeScript, Management of Software Versions, Trunk-based Development, State Machines, AWS Lambda, Indexer, Backend, Event Driven Architecture, Git Flow, Front End Software Development, Functional Programming, Api Gateway, Amazon Simple Queue Service (SQS), Terraform, Serverless Computing, Microservices - **Published:** October 1, 2026 - **Apply:** https://www.totaljobs.com/job/senior-sqs/smart-sourcer-limited-job108063488 ## About the Role * Senior/Staff-level backend mastery in C# and .NET 9/10, capable of architecting and leading distributed REST microservices at scale. * Advanced AWS serverless expertise including Lambda,API Gateway, SQS, SNS, Step Functions & EventBridge. * Serious API engineering capability: versioning, documentation, throttling, rate-limiting, contract stability, DX-first design, and building APIs that other engineers love to consume. * Some frontend experience with Typescript will be advantageous * Some real-world identity engineering: familiarity with AWS IAM, permission modelling, least-privilege design, cross-service auth patterns, and secure-by-default access controls. * Some Hands-on experience with AWS Cognito: user pools, identity pools, OAuth2/OIDC flows, JWT validation, token lifecycles, and integrating Cognito-backed auth into API Gateway and Lambda. * Data expertise across Aurora MySQL and DynamoDB: schema design, access patterns, indexing, query tuning, and pragmatic trade-offs around consistency, scale and cost. * Event-driven architecture experience with SQS: idempotency, retries, ordering, DLQs, and operational resilience. * Product-first mindset: comfortable shaping requirements, partnering with BAs, and operating without a traditional PO. * Excellent communication skills and confidence in ad hoc client interaction. * High engineering standards: Git-based workflows, trunk-based development, CI/CD (GitHub Actions), IaC (CDK/Terraform), comprehensive testing, and secure-by-default coding. * Outcome-oriented pragmatism: comfortable with ambiguity and biased toward shipping. ## Description Play a pivotal role in architecting and delivering a major greenfield B2B SaaS platform as a senior, hands-on, backend C# engineer. Expect serious backend engineering, high-performance event driven systems, and production grade AWS serverless delivery with an elevated focus on API engineering, identity & access, and secure-by-default service design. You'll also gain hands-on experience with Claude Code and modern agentic development workflows., You'll act as the technical spearhead for a greenfield product build, reporting to the Director of Engineering and working closely with their IAM Technical Lead. In addition to deep backend C#, API engineering and AWS skills, without being a security expert, you'll ideally have some experience of AWS Cognito, AWS IAM and some Typescript., * Architecting, building and shipping high-performance event driven services in C#/.NET 9/10 on AWS Lambda. * Designing secure, scalable API architectures using API Gateway, IAM, Cognito, and modern identity patterns. * Delivering resilient event-driven systems using SQS and related AWS messaging primitives. * Owning features end-to-end: product thinking, scoping, trade-offs, sequencing and delivery. * Championing engineering excellence: testing discipline, peer review, CI/CD quality, observability, performance and secure coding. * Developing hands-on skills with Claude Code: agentic workflows, smart refactoring, automated context management, and productivity-boosting AI patterns. ## Related Videos - [Why Your Best Mediors Never Become Seniors (And How to Fix It)](https://www.wearedevelopers.com/videos/2108-why-your-best-mediors-never-become-seniors-and-how-to-fix-it) - [Innovating Developer Tools with AI: Insights from GitHub Next](https://www.wearedevelopers.com/videos/1268-innovating-developer-tools-with-ai-insights-from-github-next) - [Keeping applications secure by evolving OAuth 2.0 and OpenID Connect](https://www.wearedevelopers.com/videos/100152-keeping-applications-secure-by-evolving-oauth-2-0-and-openid-connect) - [MySQL Protocol Features You Should Be Aware Of](https://www.wearedevelopers.com/videos/100267-mysql-protocol-features-you-should-be-aware-of) - [Migrating half a million users to a new payment service provider](https://www.wearedevelopers.com/videos/730-migrating-half-a-million-users-to-a-new-payment-service-provider) - [Bringing AI Model Testing and Prompt Management to Your Codebase with GitHub Models](https://www.wearedevelopers.com/videos/1536-bringing-ai-model-testing-and-prompt-management-to-your-codebase-with-github-models) ## Related Articles - [Fully Remote Software Engineer Jobs](https://www.wearedevelopers.com/magazine/447-fully-remote-software-engineer-jobs) - [Why Upskilling And Reskilling is Important For Developers](https://www.wearedevelopers.com/magazine/428-why-upskilling-and-reskilling-is-important-for-developers) - [Software Engineer Salary London](https://www.wearedevelopers.com/magazine/252-software-engineer-salary-london) - [Dev Digest 120 - Apple and peers](https://www.wearedevelopers.com/magazine/455-dev-digest-120-apple-and-peers) - [How We Built a Worry-Free System That Runs for 10+ Years – And What We’d Do Again](https://www.wearedevelopers.com/magazine/751-how-we-built-a-worry-free-system-that-runs-for-10-years-and-what-we-d-do-again) - [Is Software Engineering Over-Saturated?](https://www.wearedevelopers.com/magazine/418-is-software-engineering-over-saturated)