> For the complete documentation index, see [llms.txt](https://docs.orda.network/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.orda.network/api-reference/api-reference/authentication/important-notes.md).

# Important Notes

* **Empty bodies**: For requests with no body (e.g. GET), use the canonical empty object string `"{}"` for signature generation—not the literal empty string `""`. The API middleware and SDK sign GET requests with `"{}"`.
* **Key ordering**: The canonical JSON ensures consistent signatures regardless of object key order
* **Environment variables**: When using Postman, environment variables in the format `{{variable_name}}` are automatically resolved
* **Replay protection**: Timestamps prevent replay attacks; ensure your system clock is synchronized
* **Secret security**: Keep your client secret secure and never expose it in client-side code