Software Engineer II - Identity & Access Management

<div class="content-intro"><p><em>At Klaviyo, we value the unique backgrounds, experiences and perspectives each Klaviyo (we call ourselves Klaviyos) brings to our workplace each and every day. We believe everyone deserves a fair shot at success and appreciate the experiences each person brings beyond the traditional job requirements. If you’re a close but not exact match with the description, we hope you’ll still consider applying. Want to learn more about life at Klaviyo? Visit <a class="_ymio1r31 _ypr0glyw _zcxs1o36 _mizu194a _1ah3dkaa _ra3xnqa1 _128mdkaa _1cvmnqa1 _4davt94y _4bfu18uv _1hms8stv _ajmmnqa1 _vchhusvi _kqswh2mm _ect4ttxp _syaz13af _1a3b18uv _4fpr8stv _5goinqa1 _f8pj13af _9oik18uv _1bnxglyw _jf4cnqa1 _30l313af _1nrm18uv _c2waglyw _1iohnqa1 _9h8h12zz _10531ra0 _1ien1ra0 _n0fx1ra0 _1vhv17z1" href="http://klaviyo.com/careers" data-renderer-mark="true">klaviyo.com/careers</a>&nbsp;to see how we empower creators to own their own destiny.</em></p></div><h2>Team overview</h2> <p>The <strong>Core Infrastructure – Identity &amp; Organizations (Core IO)</strong> pillar owns the foundational substrate for identity, access, organizations, and platform integrity at Klaviyo. We manage the critical path of the user journey from login, to enforcing permissions, to operating within the correct organization and regional context so that the rest of the platform can move fast and stay secure.</p> <p>&nbsp;</p> <p>Within Core IO, the <strong>Identity &amp; Access Management (IAM)</strong> team builds and operates Klaviyo’s centralized authentication and authorization platform for both humans and machines. We power login, SSO, MFA, SCIM, internal service auth, and external API auth, and we are in the middle of transforming Klaviyo’s identity stack into a unified, enterprise-grade platform.</p> <h2>Why this role is exciting</h2> <ul> <li><strong>Shape Klaviyo’s identity platform:</strong> You’ll help design and build the services that every product team and customer relies on login, sessions, permissions, and secure service APIs are all on your roadmap.</li> <li><strong>High-leverage, platform-level impact:</strong> Your work will directly affect engineering velocity (auth as a shared service), Enterprise deal wins (SSO/SCIM/RBAC/ReBAC), and Data Residency (region-aware auth flows).</li> <li><strong>Deep systems and security learning:</strong> You’ll work on distributed systems, modern IdP integration, machine auth, and secure-by-default patterns with strong mentorship and meaningful ownership.</li> </ul> <h2>What you’ll do</h2> <p>As a <strong>Software Engineer II</strong> on the IAM team, you will:</p> <p>&nbsp;</p> <ul> <li&