API billing tools for a narrow, useful problem.

PayAPIKey helps developers and SaaS founders estimate API costs, token usage, monthly billing, rate-limit capacity, profit margin, and policy language before launching paid API access.

The first version is intentionally simple: no account system, no key marketplace, no API proxy, and no payment flow. The value is a focused brand, practical calculators, transparent source data, machine-readable documentation, and developer-focused educational content.