Auth0 vs FusionAuth.
Last verified 2026-08-19
When Auth0 wins
- Largest SDK, sample-app, and community surface in CIAM
- Auth0 FGA and packaged agent identity that FusionAuth does not match
- Vendor-attested SOC 2, ISO, HIPAA, FedRAMP via Okta
- No binary to patch; Actions instead of self-hosted lambdas
When FusionAuth wins
- MAU-independent cost, Community edition, Cloud or self-host with the same APIs
- Single-binary ops that are materially lighter than Keycloak
- You can start self-hosted and move to FusionAuth Cloud without changing vendors
- Outbound lock-in is lower than Auth0 Actions (3/5 vs 4/5)
Both win
- Both support WebAuthn passkeys natively; orchestration is average on both (3/5)
- Both support social login and B2B tenancy
- Neither is the passkey-conversion leader
Pricing comparison
| MAU band | Auth0 | FusionAuth |
|---|---|---|
| 10,000 MAU | $240/mo | $100/mo |
| 100,000 MAU | $1,200/mo | $400/mo |
| 500,000 MAU | $4,500/mo | $1,500/mo |
| 1,000,000 MAU | $9,500/mo | $3,000/mo |
Developer experience & lock-in
Editorial 1–5 scores and migration effort, on the same axes for both. Lower migration effort is better (easier to adopt, less lock-in).
| Signal | Auth0 | FusionAuth |
|---|---|---|
| DX overallDeveloper experience | 5/5✓ | 4/5 |
| Docs qualityDocumentation | 5/5 | 5/5 |
| Passkey orchestrationPasskey / WebAuthn depth | 3/5 | 3/5 |
| Adoption effortMigrating in | Moderate | Moderate |
| Lock-in (exit effort)Migrating out | Involved | Moderate✓ |
Enterprise readiness
Computed across the enterprise pillars from the capability matrix. See the enterprise-ready pillars.
| Pillar | Auth0 | FusionAuth |
|---|---|---|
| Overall | Enterprise-ready · 100 | Enterprise-ready · 88 |
| Enterprise SSO | 100 | 100 |
| Directory sync (SCIM) | 100✓ | 65 |
| Organizations & tenancy | 100 | 100 |
| RBAC & custom roles | 100✓ | 85 |
| Audit logs & streaming | 100 | 100 |
| Compliance certifications | 100✓ | 70 |
| Security posture | 100✓ | 85 |
Side-by-side capability matrix
| Capability | Auth0 | FusionAuth |
|---|---|---|
| Password authentication | ✓ Yes | ✓ Yes |
| Social login | ✓ Yes | ✓ Yes |
| Magic links | ✓ Yes | ✓ Yes |
| SMS OTP | ✓ Yes | ✓ Yes |
| Email OTP | ✓ Yes | ✓ Yes |
| TOTP (authenticator app) | ✓ Yes | ✓ Yes |
| Push MFA | ✓ Yes | ✕ No |
| WebAuthn / passkeys | ✓ Yes | ✓ Yes |
| Biometric | ✓ Yes | ✓ Yes |
| Hardware security keys | ✓ Yes | ✓ Yes |
| SAML SSO | ✓ Yes | ✓ Yes |
| OIDC SSO | ✓ Yes | ✓ Yes |
| OAuth 2.0 SSO | ✓ Yes | ✓ Yes |
| Enterprise federation | ✓ Yes | ✓ Yes |
| Passwordless-only flows | ✓ Yes | ✓ Yes |
| Adaptive MFA | ✓ Yes | ~ Partial |
| Step-up auth | ✓ Yes | ✓ Yes |
| Capability | Auth0 | FusionAuth |
|---|---|---|
| RBAC | ✓ Yes | ✓ Yes |
| ABAC | ~ Partial | ~ Partial |
| ReBAC | ✕ No | ✕ No |
| FGA engine | ✓ Yes | ✕ No |
| API authorization | ✓ Yes | ✓ Yes |
| Fine-grained permissions | ✓ Yes | ✓ Yes |
| Capability | Auth0 | FusionAuth |
|---|---|---|
| Self-service registration | ✓ Yes | ✓ Yes |
| Progressive profiling | ✓ Yes | ✓ Yes |
| Self-service account | ✓ Yes | ✓ Yes |
| Bulk user import | ✓ Yes | ✓ Yes |
| Admin user search | ✓ Yes | ✓ Yes |
| Custom user metadata | ✓ Yes | ✓ Yes |
| Organizations / tenants | ✓ Yes | ✓ Yes |
| Multi-tenancy | ✓ Yes | ✓ Yes |
| SCIM provisioning | ✓ Yes | ~ Partial |
| Capability | Auth0 | FusionAuth |
|---|---|---|
| REST API | ✓ Yes | ✓ Yes |
| GraphQL API | ✕ No | ✕ No |
| SDKs | 16 listed | 14 listed |
| CLI | ✓ Yes | ✓ Yes |
| Terraform provider | ✓ Yes | ✓ Yes |
| Local emulator | ✕ No | ✓ Yes |
| Extension model | Actions (Node.js serverless) | Lambda functions (JavaScript, in-product) + webhooks |
| Capability | Auth0 | FusionAuth |
|---|---|---|
| Bot detection | ✓ Yes | ~ Partial |
| Breached password detection | ✓ Yes | ✓ Yes |
| Brute-force protection | ✓ Yes | ✓ Yes |
| Anomaly detection | ✓ Yes | ~ Partial |
| Log streams | ✓ Yes | ✓ Yes |
| Audit logs | ✓ Yes | ✓ Yes |
| GDPR data export | ✓ Yes | ✓ Yes |
| PII minimization | ~ Partial | ~ Partial |
| Post-quantum roadmap | ✕ No | ✕ No |
| Capability | Auth0 | FusionAuth |
|---|---|---|
| MCP support | ✓ Yes | ✕ No |
| OAuth 2.1 | ✓ Yes | ✓ Yes |
| Dynamic client registration | ✓ Yes | ✓ Yes |
| Agent vs human token separation | ✓ Yes | ✕ No |
| Web Bot Auth | ✕ No | ✕ No |
| Capability | Auth0 | FusionAuth |
|---|---|---|
| SOC 2 Type II | ✓ Yes | ✓ Yes |
| ISO 27001 | ✓ Yes | ✕ No |
| ISO 27018 | ✓ Yes | ✕ No |
| HIPAA | ✓ Yes | ✓ Yes |
| PCI DSS | Level 1 (with config) | ✕ No |
| GDPR | ✓ Yes | ✓ Yes |
| CCPA | ✓ Yes | ✓ Yes |
| FedRAMP | High (via Okta) | ✕ No |
| EU data residency | ✓ Yes | ✓ Yes |
| Capability | Auth0 | FusionAuth |
|---|---|---|
| Consent management | ~ Partial | ~ Partial |
| Preference center | ~ Partial | ~ Partial |
| Purpose-specific consent | ✕ No | ~ Partial |
| Integrates with CMPs | 2 listed | n/a |
| Capability | Auth0 | FusionAuth |
|---|---|---|
| Multi-region deployment | ✓ Yes | ~ Partial |
| Data residency control | ✓ Yes | ✓ Yes |
| Proven at high scale (1M+ MAU) | ✓ Yes | ~ Partial |
| Capability | Auth0 | FusionAuth |
|---|---|---|
| Password-hash import | ✓ Yes | ✓ Yes |
| Lazy / just-in-time migration | ✓ Yes | ~ Partial |
| Account linking & dedup | ✓ Yes | ~ Partial |
| Custom domains per brand | ✓ Yes | ✓ Yes |
| Per-brand theming of all flows | ✓ Yes | ~ Partial |
| Per-brand consent partitioning | ~ Partial | ✕ No |
| Deletion webhooks / cascade | ✓ Yes | ~ Partial |
| Event streaming / webhooks | ✓ Yes | ~ Partial |
| Documented rate limits | ✓ Yes | ~ Partial |
FAQ
- Is FusionAuth open source?
- Community is free under a custom Apache-2.0-style license, not OSI-certified. For most teams that is functionally equivalent. For procurement that requires OSI, use Keycloak or Ory. Do not pick FusionAuth hoping it is Keycloak with a prettier admin UI and an OSI stamp.
- Which is cheaper at 500k MAU?
- FusionAuth. Compass estimates about $1,500/month at 500k MAU and about $3,000 at 1M, versus Auth0 at about $4,500 and $9,500. Self-host operating cost (database, HA, a fraction of an FTE) is on you. At consumer scale the Auth0 invoice is still the larger number.
- Can FusionAuth replace Auth0 Organizations?
- FusionAuth Tenants cover most B2B SaaS tenancy. Deep enterprise SSO catalogs and FGA still favor Auth0. If the leave-reason is the bill, FusionAuth is the honest landing. If the leave-reason is federation breadth, it is not.
- Should I switch from Auth0 to FusionAuth?
- Switch if per-MAU cost is why Auth0 failed, and you will own a binary or pay FusionAuth Cloud. Do not switch for agent identity, FedRAMP, or FGA. Hash import is tractable. Actions rewrites are the real work. Budget 60 to 90 days.
Auth0 sells velocity and a PDF from a compliance team. FusionAuth sells a binary and a bill that does not track MAU. Both speak OIDC. Only one of them wants to be your IdP vendor in five years of consumer scale.
Choose Auth0 when FGA, agent SKUs, or FedRAMP are on the sheet, and the team should not run auth. Choose FusionAuth when the Auth0 invoice is the meeting, you want a self-host option that is not Keycloak, and you can live without Zanzibar.
If you need Keycloak's ecosystem and OSI license, go there. If you need B2B SSO without running anything, go to WorkOS.
Profiles: Auth0, FusionAuth. Adjacent: Keycloak vs FusionAuth.