Auth0's free tier ends at 25,000 monthly active users

The workload

Building authentication from scratch is a maintenance task with no ceiling: password resets, breach-credential checks, session handling, eventually social login and single sign-on. A founder who buys Auth0 instead pays by a unit tied to how many people use the app, not how many features are switched on. Auth0's own pricing page, retrieved 16 September 2026, states a verified free allowance: "Up to 25,000 monthly active users" at no charge, identical for its B2C and B2B lines. The resulting workload is administrative: watching usage against that ceiling and budgeting the price jump when it is crossed.

What the documents show

The pricing page defines its own unit precisely, a verified claim direct from the vendor: a monthly active user is "any non-internal (non-employee) user that authenticated during a given month for a given tenant," a calendar-month, per-tenant count keyed to authentication, not creation. A second Auth0 document, the Management API reference for its active-users statistic, describes a related but distinct measurement: an endpoint returning "the number of active users that logged in during the last 30 days," a rolling window, not a calendar month. Both are verified Auth0 text, but they do not describe the same number: a dashboard built on that endpoint should not be assumed to match the billing definition.

The operating cost

Above the free tier, Auth0's verified B2C Essentials plan starts at $35 per month for 500 MAUs and scales to $3,500 at 50,000 MAUs; B2C Professional starts at $240 for 500 MAUs. The B2B product starts higher: $150 for Essentials and $800 for Professional, each also starting at 500 MAUs. The page states no per-MAU overage rate; usage between tiers is "billed at the next tier up," so one user past a threshold triggers the next block's full price, not a marginal fee. Annual billing is eleven times the monthly rate, one month free. Naming a figure for an unstated, undocumented user base would be an estimate, not a vendor fact, and none is made here.

The stop condition

The documents name a hard ceiling at 25,000 free MAUs and step changes at each tier boundary; nothing states a downgrade path if usage falls back below a tier. Editorially, the stop condition a solo operator can act on is the boundary itself: crossing it triggers a fixed jump in monthly cost, not a smooth increase, and that jump is the point to re-price the product before the next renewal.

• Does the app's own usage dashboard count MAU the same way the invoice will?
• Is the product B2C or B2B, given the two lines price identically at the free tier but diverge sharply above it?
• What is the cost at the next tier boundary, not just the current one?

Auth0's tiered, definition-driven MAU pricing is one of four authentication models this batch documents; the dollar figures above are the vendor's own numbers as published on 16 September 2026, not a projection of what any app will owe.