Getting Started with Circle APIs


All Circle APIs use API keys as the mechanism to authenticate client requests.

The API key must be set in the Authorization header of the request sent from your backend server. The format of the header is Bearer secret-key-value.

Authorization: Bearer YOUR_API_KEY

API requests without authentication will fail. It is also important to note that all API requests must be made over HTTPS.

API Keys


Keep Your API Keys Safe

Your API keys allow access to privileged operations on Circle APIs, so you must keep them secure at all times. Ensure your API key is always stored securely and never share it or record it in a medium that might be publicly accessible such as client-side code, public repositories, etc.

The Sandbox Environment

The Circle APIs are available on a sandbox environment which is ideal for quickly familiarizing yourself with the request & response formats and building prototypes.

If you don't yet have an API key on the sandbox environment, you can easily generate one by creating an account - it only takes a few seconds.

Create a sandbox account

If you have already created your account on the sandbox environment and generated your API key, then follow the next steps in the documentation below to get started with Circle APIs.

We can't wait to see what you are going to build!