Software Engineer

About the Role

As a Software Engineer, you will design, build, and operate the identity and authorization systems that protect critical interactions on Replit, including Agent acting on behalf of a user or holding their own identity.

The work is guided by a few simple questions:

• Can every protected request prove which workload made it, which principal it represents, and who is acting on that principal's behalf?
• Can product teams express policy once and trust the same decision across web, mobile, Agent, and internal services?
• Can enterprise administrators control who can access each workspace, app, connector, and Agent capability without navigating a permission maze as well as having a legible ledger of decisions?
• Can Agent act for a user across long-running and durable work without receiving broad or long-lived credentials?
• Are identity and authorization fast, reliable, highly available, and observable enough for the product flows that depend on them?

What you'll do

• Design and operate central authorization interfaces with typed principals, actions, resources, decisions, explainable deny reasons, privilege attenuation, delegations, and obligations
• Evolve enterprise roles, groups, app access, entitlements, and workspace policy so common cases stay simple and advanced cases remain possible
• Build and operate Replit's Security Token Service and workload identity using OAuth 2.0 token exchange, JWT/OIDC, SPIFFE/SPIRE, and mTLS
• Threat-model delegation, confused-deputy risks, and cross-tenant movement, then make secure, fail-closed behavior the default
• Lead compatible migrations with shadow evaluation, feature gates, telemetry, and rollback plans, and own the SLOs, incidents, and operational health of the systems you ship
• Partner with Agent, Connectors, Enterprise, Security, and Infrastructure teams to turn product requirements into shared platform primitives
• Research and develop new innovative approaches to Authx in the Agentic world

Required skills and experience

• Experience shipping and operating security-sensitive backend or distributed systems in production, including reliability, performance, incidents, and observability
• Depth in authentication, authorization, or identity systems, such as OAuth 2.0/OIDC, JWT, mTLS, Identity Federation, RBAC, ReBAC, PBAC, Zanzibar, Macaroons, Biscuits, Cedar, or policy engines. You do not need prior experience with every item
• Strong understanding of multi-tenant security, least privilege, delegation, privilege attenuation, auditability, and threat modeling
• Experience migrating security-sensitive systems without breaking callers. Approaches can include typed contracts, shadow evaluation, and staged enforcement
• Fluent in at least one production backend stack. Our systems use TypeScript, Go, Rust, Postgres, gRPC/Protobuf, Kubernetes, Envoy, and Restate
• Able to make and communicate tradeoffs across security, reliability, latency, product experience, delivery speed, and long-term maintainability

If you're excited about this role but don't meet every requirement, we still encourage you to apply.