Get an API key

Free tier: 1,000 requests/day across every calculator. No credit card required. We use a magic link instead of passwords — enter your email and we'll send you a sign-in link.

By signing in you agree to the Proload API terms and privacy policy. Free tier: 1,000 requests/day. No card required.

What you get

  • 1,000 requests/day across every calculator endpoint on the free tier.
  • Paid plans available — Pro ($9/mo, 100k req/mo) and Studio ($29/mo, 1M req/mo), with metered overage.
  • No credit card required to start — sign up with email only.
  • Stable HTTP API with deterministic ETags so you can cache aggressively.
  • Revoke any time from this page. Keys are hashed at rest.

How to use your key

Pass your key on every request in the Authorization header: 

curl -X POST https://api.proload.online/v1/one-rep-max \
  -H "Authorization: Bearer pk_live_..." \
  -H "Content-Type: application/json" \
  -d '{"weight": 225, "reps": 5, "unit": "lb"}'

Read the API documentation for the full schema.