Sr Software Engineer, Applications

Basis

1d•$119,051 - $165,000•Hybrid

About The Position

At Basis, we empower agencies and brands with cutting-edge software that automates digital media operations. Our all-in-one platform supports seamless planning, reporting, and financial reconciliation across direct, programmatic, search, and social media. We’re not just building advanced technology; we’re also building a culture where passionate, motivated individuals come together to drive meaningful change. Our commitment to inclusivity and growth ensures our employees thrive both professionally and personally. With our headquarters in Chicago, we offer flexible work options across the U.S. and Canada, including remote, hybrid, or on-site at headquarters. The Auth team owns the systems that decide who can do what across Basis: authentication, identity, and fine-grained authorization for a platform built on complex agency and org hierarchies. We're an enabling team: every product team at Basis depends on the primitives, policies, and infrastructure we build and own. That now includes authorization for AI agents operating alongside human users, not just human users alone.

Requirements

5+ years of professional software engineering experience.
Deep, hands-on knowledge of OAuth 2.0 and OpenID.
Experience with ReBAC systems (OpenFGA, Zanzibar, SpiceDB): modeling schemas, writing and testing tuple-based policies, and reasoning about permission evaluation performance.
Experience with Auth0 or a comparable identity provider (Okta, Azure AD, Keycloak).
Strong backend skills in Java, Ruby, or Python, with frameworks such as Spring Boot, Rails, or Django.
Regular use of AI coding tools (Claude Code, Cursor, Codex) for code generation, debugging, and exploring unfamiliar code, and the judgment to own and vet what they produce.
A collaborative approach to design and decision-making, and a commitment to building an inclusive team.

Nice To Haves

Experience building or scaling auth systems for a platform with complex organizational hierarchies (agencies, multi-tenant SaaS, etc.).
Familiarity with policy-as-code or attribute-based access control (ABAC).
Background in ad tech or programmatic advertising.
Contributions to open-source identity or authorization projects.

Responsibilities

Extend our identity layer in Auth0: authentication flows, token issuance, identity federation.
Build and maintain our ReBAC authorization model in OpenFGA, the system every authorization decision on the platform runs through.
Own the details of OAuth 2.0 and OIDC in our stack: token flows, JWKS validation, scopes, audience restrictions.
Define how AI agents authenticate and receive scoped permissions, so non-human actors operate under the same authorization model as people.
Drive technical projects that cut across multiple teams and systems, from design through production.
Set technical direction and quality standards for the team and review the work that ships against them.
Support and mentor other engineers through code review, design discussions, and day-to-day collaboration.