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 is seeking a Senior Full Stack Engineer to develop secure APIs and solutions integrating IAM with core applications. The role requires strong skills in TypeScript, C#, and AWS while embracing a security-first mindset. Ideal candidates will have a background in building RESTful APIs and working with OIDC-compliant identity providers. This permanent position offers a competitive salary of £85k-£90k with bonuses and a mostly remote work arrangement.

Benefits

Bonus

Benefits

Qualifications

• Strong full-stack development skills using TypeScript and C#.
• In-depth understanding of security protocols like Zero Trust and OAuth2.
• Solid experience with AWS services such as IAM and Lambda.

Responsibilities

• Build full-stack APIs and integrations in TypeScript, C#, AWS IAM.
• Deliver secure login, SSO, MFA, and tenant isolation leveraging AWS services.
• Collaborate across teams to embed identity into new features.

Skills

Full-stack development skills

Security mindset

Experience with OIDC-compliant IDPs

Solid AWS expertise

RESTful API development

Secure coding practices

Tools

TypeScript

C#

AWS

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