> For the complete documentation index, see [llms.txt](https://circular-protocol.gitbook.io/standard-apis/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://circular-protocol.gitbook.io/standard-apis/api-docs/apis.md).

# APIs

## URL and Body Structure

The typical URL and body structure adheres to the following formats:

```json
URL = [NAG URL]Circular_[Network End Point]

Body = { 
"NAGKEY":[NAG KEY], 
"TBody":[Transaction body] 
}
```

Each NAG has a unique URL. Data is sent as a JSON payload through a POST HTTPS request. The payload contains the data that the NAG will send to the blockchain Network. When successfully executed, all endpoints will respond with a Result of 200, and the Response field will provide the required data or error details in JSON format.

The NAG URL for the Testnet is: <https://nag.circularlabs.io/NAG.php?cep=>\
For the Mainnet use: [ https://nag.circularlabs.io/NAG\_Mainnet.php?cep=](< https://nag.circularlabs.io/NAG_Mainnet.php?cep=>)