Email API limits: when you hit one
2 provider limits with the provider's own sentence and check date. The link in each section gives the verdicts at twice a typical monthly workload.
Postmark: Credits run out
No extra usage: when the included credits are used up, calls stop until the next period or a new plan.
- Free (Developer): no extra usage
No overages allowed in this plan.
Source: postmarkapp.com/pricing
Checked 2026-11-11
Plans that clear it: Mailgun Basic (extra usage allowed); Mailgun Foundation 50K (extra usage allowed); Mailgun Scale 100K (extra usage allowed).
Resend: Credits run out
No extra usage: when the included credits are used up, calls stop until the next period or a new plan.
- Free: no extra usage
Continue sending and receiving emails beyond your quota. Resend automatically charges your plan's overage rate for each additional bucket of 1,000 emails. Available to paid subscriptions.
Source: resend.com/pricing
Checked 2026-11-11
Plans that clear it: Mailgun Basic (extra usage allowed); Mailgun Foundation 50K (extra usage allowed); Mailgun Scale 100K (extra usage allowed).