Auth0 vs Clerk vs WorkOS: what "authentication as a service" actually costs at scale

The free tiers here are wildly different sizes, and that's the first thing worth knowing before you pick one. Auth0's free plan covers 25,000 monthly active users. Clerk's covers 50,000. WorkOS covers up to **1 million** MAU on its standard AuthKit product — you only start paying when an enterprise customer needs SSO or SCIM, at $125 per connection per month with volume discounts.

That last detail explains WorkOS's whole positioning: it's not really competing on consumer-scale auth pricing at all. It's the tool you reach for specifically because a big customer's IT department is demanding SAML SSO before they'll sign, and $125/month per connection is cheap compared to losing the deal.

Auth0 and Clerk compete more directly with each other, and at standard scale Clerk tends to run noticeably cheaper — real-world estimates put Clerk around $2,500–$3,000/month against $4,000–$5,000/month for a comparable Auth0 setup, though that gap narrows past 1M MAU and depends heavily on how many enterprise SSO connections you're carrying.

| | Free MAU | Where the bill grows |
|---|---|---|
| WorkOS | 1,000,000 | per SSO/SCIM connection ($125 ea.) |
| Clerk | 50,000 | active-user tiers past free |
| Auth0 | 25,000 | active-user tiers, add-ons (FGA, orgs) |

If you're pre-product-market-fit and just need login to work, any of the three free tiers gets you there — Auth0's 25K ceiling is the one you'll hit first, which matters if growth is the whole plan. If your app is a Next.js product and you want auth that doesn't feel bolted on, Clerk's developer experience is the reason people choose it over the price. If your actual problem is "enterprise buyer #1 needs SSO next month," skip straight to WorkOS — it was built for exactly that sentence.