UsageRail is an API monetization platform for small teams. Its open-source SDK checks customer API keys and enforces per-customer rate limits and quotas inside your server. The hosted service handles plans, checkout and usage billing through your own Stripe account. We launched on October 28, 2026.

What UsageRail is

Add the SDK to your API server and your customers can create their own API keys, stay inside the rate limits and quotas of their plan, pay through Stripe Checkout and see their usage in a hosted portal. At the end of each billing period, usage goes onto the customer's Stripe invoice.

Two things set the design apart. Requests never pass through us: the SDK checks keys and limits in your process and sends us per-minute totals. And the money never passes through us either: payments go straight to your Stripe account, and UsageRail takes no percentage of them. The docs describe each part, and pricing lists what each plan includes.

What's open source

The SDKs are MIT licensed and public, so you can read exactly what runs in your server and what it sends:

  • Source: the usagerail/sdk repository on GitHub
  • Node.js: @usagerail/node on npm, with adapters for Express, Hono, Fastify and Next.js
  • Python: usagerail on PyPI, with adapters for FastAPI, Flask and Django

How we test what we publish

  • The example files in our Stripe usage-based billing tutorial and API rate limiting guide are read directly from projects in our repository. Those projects run their tests in CI.
  • We measure the SDK's overhead per request with a benchmark script in the SDK repository. The docs give the machine, the measurement date and what the benchmark excludes.
  • The Next.js on Vercel and Cloudflare Workers pages report what we measured when we load-tested the SDK on those platforms.

How we check prices and facts

Guides such as API monetization and usage-based pricing quote real prices from other companies. Each one is read from that company's own pricing page or documentation, never from a third-party summary, and the page says when it was checked.

The usage-based billing software comparison is re-checked every month. We build one of the tools on that page, so we aren't neutral, and the page says so. UsageRail's entry there lists what it doesn't cover.

If you find a number that's out of date or a statement that's wrong, email support@usagerail.com and we'll fix it.

Contact

Support, billing questions and corrections: support@usagerail.com.