Clerk Charges $1,825/mo at 100K Users. Supabase Auth Charges $25. Same Features.

I was migrating my SaaS from Firebase to a dedicated auth provider and almost made a $21,000/year mistake.

Here's what happened: I had 85,000 MAU and growing. Clerk's landing page looked great — beautiful pre-built components, easy integration, good docs. I was about to commit when I decided to actually calculate the cost at scale.

The Math That Changed My Mind

I built a calculator to compare every major auth provider at different scales. Here's what the numbers look like at 100K monthly active users:

ProviderFree TierCost at 100K MAUSupabase Auth50,000 MAU$25/moWorkOS1,000,000 MAU$0/moFirebase Auth50,000 MAU$275/moClerk10,000 MAU$1,825/moAuth07,500 MAU$5,000+/mo