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

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

Job summary

A global B2B SaaS leader is seeking a Senior Full Stack Engineer to develop secure APIs in a dynamic, AI-driven environment. You will work on integrating IAM solutions and implementing Zero Trust authentication methods. The ideal candidate will have strong skills in TypeScript, C#, and AWS, along with a security-first mindset. This role offers a salary between £85k and £90k, along with bonuses and benefits, and allows for 95% remote work.

Benefits

Bonus

Benefits

95% remote work

Qualifications

• Strong full-stack development skills in TypeScript, C#, and AWS.
• Understanding of security principles including Zero Trust and OAuth2.
• Experience with OIDC-compliant identity providers like Auth0 or Cognito.

Responsibilities

• Build full-stack APIs and integrations in TypeScript, C#, and AWS IAM.
• Deliver secure login features including SSO, MFA, and RBAC/ABAC.
• Collaborate with cross-functional teams to embed identity into new features.

Skills

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)

Building RESTful APIs

Mentoring and problem-solving skills

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