All Circle APIs use API keys as the mechanism to authenticate client requests.
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 Circle APIs are available on a sandbox environment which is ideal for quickly familiarizing yourself with the request & response formats and building prototypes, and writing your integration code.
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.
Updated about a month ago