Auth0 → FusionAuth

Auth0 charges by monthly active user, so a growing consumer app sees its bill follow its audience. FusionAuth offers a different structure: a free self-hosted edition with no user cap, and paid tiers that add features and hosting. That changes where cost appears, though the paid cloud tiers are not cheap at the top end.

Auth0 plans at a glance

Auth0 publishes separate B2C and B2B self-serve pricing. The Free plan, $0 per month for up to 25,000 MAUs, appears in both. B2C Essentials begins at $35 per month for 500 MAUs and B2C Professional at $240 per month for the same tier. B2B Essentials begins at $150 per month for 500 MAUs and B2B Professional at $800. Enterprise is a contact-sales plan in both tracks, and billing yearly equals 11 months of the monthly price.

FusionAuth editions

• Community: free, self-hosted only, described on the pricing page as unlimited, with core authentication standards, OAuth 2.0, OpenID Connect, SAML v2 login, registration and basic MFA.
• Starter: from $162 per month, billed annually, hosted on FusionAuth Cloud with basic hosting. It adds premium features such as breached password detection and advanced MFA.
• Essentials: from $2,970 per month, billed annually, with business hosting, custom OAuth scopes and email support with a 24 to 48 hour response during business hours.
• Enterprise: also listed from $2,970 per month, billed annually, with high availability hosting, advanced threat detection, 24/7 support and a solution architect.

The pricing page shows a MAU selector, so the figures above are starting points and the final price depends on the user count you choose.

What migration involves

FusionAuth publishes a dedicated Auth0 migration guide. Users come out of Auth0 as JSON. Password hashes need a separate support ticket because Auth0 treats them as sensitive, and the guide says a paid Auth0 plan is required. Its author reports roughly one week for the request, though that is one account and timing will vary. Auth0’s own documentation describes an eligibility review and a signed acknowledgment before an encrypted file is delivered.

The guide describes Auth0 hashes as bcrypt, and FusionAuth’s import script handles that format, so users can sign in with their existing passwords after a bulk import through the Import API. Social login users can be linked by provider identifier, or by email or username, or left pending until the user confirms.

FusionAuth’s migration overview lists three paths: bulk offline import, segment-by-segment, and a slow user-by-user migration through Connectors. Connectors require at least a Starter plan. They authenticate against the old system and move the user at login, which suits a team that cannot get hashes from Auth0. The overview also says the User API does not carry passwords when importing single users.

Application code that speaks OIDC or SAML needs new endpoints and client settings. Logic written as Auth0 Actions must be rebuilt as FusionAuth lambdas, and the guide cautions that functionality is not identical.

The trade-offs

Self-hosting Community removes the per-user charge but brings database, upgrade and uptime duties. Premium features such as advanced MFA methods, LDAP integration and custom registration forms are not in Community. The jump from Starter at $162 to Essentials at $2,970 is large, so teams that need business support or custom scopes should price that step early.

For a small app, Auth0’s free tier up to 25,000 MAUs is hard to beat. FusionAuth becomes interesting when per-MAU billing starts to dominate, or when owning the user database matters.