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  2. Clerk vs Supabase Auth vs Auth0 for sign-in

Clerk vs Supabase Auth vs Auth0 for sign-in

All three have a free plan that covers a new app. The differences show up when you need paid features or pass the free user limits. Supabase Auth stays cheapest at scale, partly because its price covers your whole Supabase project, database included.

Priced from vendor pages
Prices checked
20 Oct 2026
Exchange rate
1 USD = £0.7489
Sources
4
How we check

The answer

Up to 25,000 users a month, all three can be free. At around 60,000 users, Supabase Pro is £18.72 a month and Clerk Pro is £168.50. Auth0 doesn't publish a price at that size.

What does sign-in cost as your user count grows?

Clerk

Hobby (free, 50,000 retained users) or Pro $25/mo ($20/mo billed annually), 50,000 included then $0.02 each

  • A free plan for up to 50,000 retained users, with organisations for B2B apps (100 included on any plan).

Hobby has no multi-factor sign-in and keeps Clerk branding; both need Pro. Past 50,000 retained users, each extra user is $0.02 a month.

~1,000 users a month, free features only FreeEntry paid plan, billed monthly £18.72~60,000 users a month £168.50

Supabase Auth

Free (50,000 monthly active users) or Pro $25/mo (100,000 included, then $0.00325 each)

  • The lowest cost at scale, and sign-in sits next to your database, so row-level security rules can check who is signed in.

Free projects pause after a week without activity. The price is for the whole Supabase project, not sign-in alone. Phone-based multi-factor sign-in is an extra $75 a month on Pro.

~1,000 users a month, free features only FreeEntry paid plan, billed monthly £18.72~60,000 users a month £18.72

Auth0

Free (25,000 monthly active users) or B2C Essentials from $35/mo (up to 500 monthly active users); B2B Essentials from $150/mo

  • A free plan for up to 25,000 monthly active users, with unlimited social logins and one custom domain.

Prices are published in tiers up to 50,000 users (B2C Essentials: $70 at 1,000, $700 at 10,000, $3,500 at 50,000 a month); above that you contact sales. Usage between tiers is billed at the next tier up. Pro multi-factor sign-in needs a paid plan, and a custom domain needs card verification.

~1,000 users a month, free features only FreeEntry paid plan, billed monthly £26.21~60,000 users a month Price not published
~1,000 users a month, free features onlyFree
~1,000 users a month, free features onlyFree
~1,000 users a month, free features onlyFree
Entry paid plan, billed monthly£18.72
Entry paid plan, billed monthly£18.72
Entry paid plan, billed monthly£26.21
~60,000 users a month£168.50
~60,000 users a month£18.72
~60,000 users a monthPrice not published

Monthly cost in pounds, from each vendor's pricing page. Lowest figures compared user counts aren't measured the same way.

How we worked it out

  • Clerk Pro $25 × 0.7489 = £18.72 (18.7225). Billed annually it's $20 × 0.7489 = £14.98 a month.
  • Clerk at ~60,000 retained users: $25 + (60,000 − 50,000) × $0.02 = $225 × 0.7489 = £168.50 (168.5025).
  • Supabase Pro $25 × 0.7489 = £18.72. Pro includes 100,000 monthly active users, so ~60,000 costs nothing extra.
  • Auth0 B2C Essentials $35 × 0.7489 = £26.21 (26.2115), for up to 500 monthly active users. Auth0's free plan stops at 25,000 users, and its published tiers stop at 50,000, so there is no price for 60,000. B2B Essentials starts at $150 a month.
  • The three count users differently. Clerk counts retained users: people who come back at least 24 hours after signing up. Supabase and Auth0 count monthly active users. The same app can show different numbers on each.
  • Excludes VAT, SMS costs, enterprise single sign-on and add-ons.

Sources