API quota: how usage quotas work, with examples

What is an API quota?

An API quota is the number of calls included in a plan over a billing period, such as 100,000 requests a month. Going over triggers overage charges or refused calls, depending on how the quota is set up.

How API quotas work

Each key’s calls are counted as they happen. When the count reaches the quota, the API either keeps serving and bills the extra as overage, or stops serving until the quota reset at the start of the next period. Good APIs warn customers well before they reach the limit.

Soft vs hard quota

A soft quota is a warning threshold: the customer is told, and usage may carry on into overage. A hard quota is a ceiling: further calls are refused with an API quota exceeded error. Many plans combine the two, with a soft warning at 80% and a hard stop at a multiple of the included volume to cap surprise bills.

An API quota example

A plan includes 100,000 calls a month, with overage at $1 per thousand. A customer makes 112,000 calls. With a soft quota they pay for 12,000 extra calls, $12. With a hard quota at 100,000, the last 12,000 calls are refused.

Quotas per customer

Micro SaaS API Marketplace enforces hard and soft limits per key, so one customer’s usage never counts against another’s, and the enforcement holds under concurrent calls.

Last reviewed 2026-11-01.

Related terms

  • Rate limit — A rate limit caps how many requests a client can make to an API in a short window, such as 100 requests a minute, to protect the service from overload and abuse.
  • Overage — An overage charge is what a customer pays for usage beyond the quota included in their plan, billed at a per-unit rate, such as a price per thousand API calls above the monthly allowance.
  • Metered billing — Metered billing charges customers for what they actually used during a billing period, such as API calls, messages sent or gigabytes stored, rather than only a fixed subscription fee.

All glossary terms →