Senior Fullstack Engineer - Identity Platform for Enterprise SaaS

About the Role

We are hiring a Senior Fullstack Engineer to join our Identity Platform team at Zapier. This Senior Fullstack Engineer remote position is crucial for building and maintaining enterprise authentication infrastructure that supports our mission of enabling companies to create dependable AI workflows at scale. You will play a key role in designing and extending systems that handle SAML SSO, SCIM provisioning, OAuth/OIDC flows, and more, ensuring that our customers have reliable and secure experiences.

What You'll Do

• Design and maintain authentication and session systems including SAML, SCIM, OAuth/OIDC, MFA, login, sign-up, and 2FA, as Zapier scales to larger and more security-conscious customers.
• Own user session propagation and JWT validation across a multi-service architecture spanning Python, Node.js, and Go.
• Build enterprise authentication controls and governance APIs: forced SSO, domain capture, credential lifecycle, and admin authentication policies.
• Develop and maintain platform libraries consumed by dozens of internal teams, ensuring reliability, latency, and efficiency are non-negotiables.
• Respond to authentication-related incidents and participate in on-call rotation to maintain system integrity.
• Enable Security, Enterprise Response, and product team partners to move faster by removing authentication bottlenecks and proactively surfacing what they need.

Requirements

• Hands-on experience building identity systems for enterprise SaaS at scale, with a deep understanding of SAML, SCIM, OAuth/OIDC, or JWT.
• Experience with multi-tenant SaaS environments and knowledge of authentication protocols.
• Ability to work through AI agents, directing and reviewing agent-written code in your daily workflow.
• Comfortable across the stack, with experience in backend services using Python and Node.js, and familiarity with React for building admin tooling.
• Proven ability to ship working software quickly, even in ambiguous situations, and to gather evidence to drive alignment.
• Strong communication skills, with a focus on written artifacts, working demos, and prototypes as primary communication tools.

Nice to Have

• Experience with Kubernetes, Terraform, and CI/CD pipelines.
• Familiarity with enterprise security standards and compliance requirements.
• Experience in building APIs that are consumed by other engineering teams.

What We Offer

• Competitive salary range of $140,000 - $200,000 per year.
• Fully remote work environment with flexible hours.
• Opportunities for professional development and growth.
• Participation in yearly company retreats across various cities in North America.
• A culture that encourages innovation and the use of AI tools responsibly.