Fusionauth

FusionAuth is a customer identity and access management (CIAM) platform with a notably complete API for user lifecycle management, OAuth2/OIDC, SSO, advanced MFA, and enterprise identity features like user data exports and GDPR compliance tooling. For agents that need to manage users programmatically — provisioning, deprovisioning, role management, login policy configuration — FusionAuth's API surface is more comprehensive than simpler auth libraries. The self-hostable option appeals to teams with data residency requirements.

The API covers user management, application registration, OAuth flows, tenant management, roles and groups, webhooks, and audit log access. The breadth is meaningful for agents managing identity operations at scale — programmatic user provisioning and deprovisioning, role assignment, SSO application management, and compliance-oriented user data management are all available through a consistent API.

Authentication for FusionAuth uses API keys with configurable permission sets. The permission model enables scoped API keys that cover only the operations an agent needs — user read/write without application management access, for instance. That granularity is appropriate for identity management contexts where broad credential access represents significant risk.

Reliability for CIAM depends on the deployment model. FusionAuth Cloud provides managed reliability; self-hosted deployments are the team's operational responsibility. Identity system availability is particularly important to get right — FusionAuth's architecture supports high-availability deployment configurations for self-hosted scenarios, but teams must implement them.

Documentation is thorough and reflects the depth of FusionAuth's feature set. The API reference is complete, and conceptual guides for OAuth, MFA, SSO, and tenant configuration are available. Teams implementing complex identity scenarios will find the docs sufficient, though the breadth of FusionAuth's features means some scenarios require reading multiple guide sections to understand the interaction between components.