Quick answer
Auth0 - Auth0 wins for most builders who need higher free-tier user ceilings and a more conventional path from hobby project to small production app, while ZITADEL wins if you want unlimited users and organizations on the free plan and can live with its tighter daily activity cap.
How the free tiers compare
These are both identity platforms, but their free tiers optimize for different constraints. Auth0 is the more familiar starter for teams that expect steady growth in monthly active users and want a broader free feature set for app auth, orgs, SSO, SCIM, and custom domains, though the free plan is capped at 25,000 MAUs and even the custom domain note includes credit card verification. ZITADEL is more generous on raw object limits: unlimited users and unlimited organizations, plus all security features, but it limits you to 100 daily active users and 3 identity providers. That makes ZITADEL better for low-traffic internal tools or early prototypes with many stored accounts, while Auth0 is better when actual active usage rises beyond a tiny daily footprint.
Auth0 vs ZITADEL free tier, side by side
| Auth0FTV 52 | ZITADELFTV 51 | |
|---|---|---|
| Free user capAuth0 measures free usage by MAUs; ZITADEL measures free usage by DAUs. | Up to 25,000 monthly active users | 100 daily active users |
| OrganizationsZITADEL is much looser here. | 5 | Unlimited |
| Identity providersThe products count different things, so this is not a perfect apples-to-apples match. | Unlimited social connections; 1 enterprise connection | Up to 3 identity providers |
| Custom domainAuth0 notes credit card verification is required for the free custom domain. | 1 custom domain | Custom domain included on Pro |
| Security and access featuresFeature naming differs, but both cover core auth basics. | Passwordless, MFA, SCIM, self-service SSO, basic attack protection | All security features, passwordless, MFA, passkeys, RBAC |
After you outgrow the free tier
Both products use flat monthly pricing for their first paid tier, then move to contact-sales enterprise plans. Auth0 starts at $35/month for Essentials and $240/month for Professional, so the jump is steep once you need more than the free tier. ZITADEL’s Pro tier starts at $100/month and includes 25,000 DAUs, so it is pricier at the first step but simpler. Based on the provided plans, there is no usage-based math to work out beyond the plan thresholds, so the main divergence is the entry price and what each free tier allows before upgrade.
Cost at real usage
| Usage | Auth0 | ZITADEL |
|---|---|---|
| Low-traffic prototype with 80 daily active users and 2 identity providersBoth stay within free-tier limits. | Free | Free |
| Small public app with 500 monthly active users and 1 custom domainAuth0’s free cap is MAU-based; ZITADEL’s is DAU-based, so this is only illustrative. | Free | Free |
| Growing app with 1,000 daily active users and 2 identity providersZITADEL would exceed its 100 DAU free cap, while Auth0 is still within its 25,000 MAU free cap if those users fit within that monthly count. | Free | $100/mo |
| Team needing paid basics plus higher auth limitsThis compares the first paid tier for each product, not equivalent feature bundles. | $35/mo | $100/mo |
Estimates, not quotes. Usage-based rates change - verify with the vendor's pricing page before committing.
When to pick each one
Pick Auth0 when…
- You expect more than 100 daily active users but still want to stay on a free plan for as long as possible.
- You need free support for SSO, SCIM, enterprise connections, and multiple organizations in a mainstream auth stack.
- You want a free tier that is easier to map to production-style usage measured in monthly active users.
- You may need a custom domain on the free plan and are okay with the stated credit card verification requirement.
- You want a clear paid upgrade path starting at a low flat monthly price.
Pick ZITADEL when…
- You need unlimited users on the free tier for a prototype, demo, or internal directory app.
- You are building a multi-tenant app with many organizations but very low daily activity.
- You want all security features available before paying, rather than a broader active-user allowance.
- You only need a small number of identity providers, up to 3, and can stay within that limit.
- You prefer a free plan that is more generous on stored accounts than on daily usage.
Bottom line
For most builders, Auth0 is the safer default because its free tier is tied to monthly active users and can carry a small production app farther before you pay. ZITADEL is the better free-first choice if your app needs unlimited stored users and organizations but only light daily traffic. Once you do pay, Auth0 starts cheaper, while ZITADEL’s first paid step costs more but comes with a larger DAU allowance. For common startup auth needs, Auth0 usually fits better.
Read the full listings: Auth0 and ZITADEL. Scores use the FTV methodology at /ftv. Browse more head-to-heads on /compare, or see the top-ranked free tiers on /top.