Senior Full Stack Engineer – Typescript, C#, AWS, IAM, Security

Smart Sourcer; Remote; GBP 85,000 - 90,000; Full time

Job summary

A leading SaaS company in the UK seeks a Senior Full Stack Engineer to develop APIs and integrate security features. The ideal candidate has strong skills in TypeScript, C#, and AWS, with a focus on Zero Trust principles. This role involves building secure applications and collaborating across teams in a remote-friendly environment. Offering a competitive salary of £85k-£90k plus bonuses and benefits, this is a fantastic opportunity to work in a cutting-edge, AI-driven organization.

Benefits

Bonus

Benefits

95% remote work

Qualifications

• 5+ years of experience in full-stack development.
• Understanding of security principles and frameworks.
• Experience building robust RESTful APIs.

Responsibilities

• Build full-stack APIs and integrations in TypeScript, C#, AWS IAM.
• Deliver secure login, SSO, MFA, and tenant isolation at scale.
• Collaborate across teams and uphold engineering excellence.

Skills

Strong full-stack development skills (TypeScript, C#, AWS)

Security mindset with understanding of Zero Trust & OAuth2

Experience with OIDC-compliant IDPs (Auth0, Okta, Cognito)

Solid AWS expertise (IAM, Lambda, API Gateway, CDK)

Experience in secure coding and threat modelling

Ability to mentor and collaborate

Job description

Senior Full Stack Engineer – Typescript, C#, AWS, IAM, Security

Outstanding opportunity to join this global B2B SaaS leader as a Senior Full Stack Engineer with some security and IAM exposure required to develop APIs to connect their IAM solution to their core applications. This permanent role offers the chance to shape how full stack applications embrace Zero Trust authentication and authorization services in a cutting-edge, AI-driven environment.

About the Role

• Build full-stack APIs and integrations in TypeScript, C#, AWS IAM
• Deliver secure login, SSO, MFA, RBAC / ABAC, and tenant isolation at scale, leveraging AWS services (Lambda, IAM, CloudFront, API Gateway, CDK)
• Collaborate across Product, Security, and Engineering teams, embed identity into new features, and uphold engineering excellence through CI / CD, testing, and incident response

Required experience

• Strong full-stack development skills (TypeScript, C#, AWS)
• An in-depth security mindset with an understanding of Zero Trust & OAuth2
• Proven experience with OIDC-compliant IDPs (Auth0, Okta, Cognito)
• Solid AWS expertise (IAM, Lambda, API Gateway, CDK)
• A proven background in building RESTful APIs that interact with IDPs
• Security-first mindset with experience in secure coding, threat modelling, and protecting PII
• Ability to mentor, collaborate, and lead with hands-on problem-solving

£85k-£90k + bonus + benefits. 95% remote & London