> For the complete documentation index, see [llms.txt](https://docs.fastnode.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.fastnode.io/getting-started/api-keys.md). # API Keys Your API key authenticates every request to FastNode. This page explains how keys are issued and how to keep them secure. ## Getting a key API keys are issued **automatically** when you sign up. After you order a node or request a free test, the key is sent to the email address on your account — no extra steps needed. Each key is tied to the node it was issued for and works with every method available on that network. Keys start with the `FN` prefix and are 64 characters long (e.g. `FNxxxx…`). ## Using a key FastNode passes the key as part of the endpoint path: ``` https://.fastnode.cc// ``` For example: ``` https://eth.fastnode.cc/YOUR-API-KEY/ ``` {% hint style="warning" %} Treat your API key like a password. Anyone with the key can send requests billed to your account. Never commit keys to source control or expose them in client-side code. {% endhint %} ## Security best practices * **Store keys in secrets managers** or environment variables — not in your codebase. * **Never expose keys client-side** — route requests through your own backend. * **If a key leaks**, contact **** to have it reissued immediately. ## Rate limits & plans Each plan has its own request-per-second limit and monthly quota. When you exceed a limit, requests return an [error](/reference/error-codes.md#rate-limits). You can monitor usage in real time from the [Monitoring](/advanced/monitoring.md) dashboard. Need higher limits or a dedicated node? Contact ****. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.fastnode.io/getting-started/api-keys.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.