Billing and usage
You pay for checked words. Plans and prices are on the API page.
What is counted
The words of the text you send are counted, as a word processor would. Every response states the number in words. Only a 200 response is billed; GET /v1/usage and GET /v1/models are free.
Plan and period
A plan includes words per month; beyond that, extra usage counts per 1,000 words. usage.period_end gives the end of the current period as Unix time; counting then starts from zero. The test key has a one-time quota without a period.
Cost cap
Every key has a cap on extra usage, 200 € per month to start with. Once it is reached, the API answers 402 cost_cap_reached instead of charging more. We change the cap on request.
Several keys
Several keys of one subscription share quota and cap. When a key is replaced, the usage stays.