---
updatedAt: 2025-02-19T23:42:20.000Z
agentTools:
  projectIndex: https://documentation.safecube.ai/llms.txt
---

# Mandatory Headers

There are some headers that are mandatory in a REST API request, while others are optional. Here are some examples of mandatory headers that you should include in your REST API requests. **In general, these headers are generated by the client sending the request.**

* Host: This header specifies the hostname of the server that the request is being sent to. It is mandatory in HTTP/1.1 and later versions of the protocol.
* Content-Type: This header specifies the format of the data being sent in the request body. It is mandatory when the request includes a message body (such as with a POST or PUT request).
* Content-Length: This header specifies the length of the message body in bytes. It is mandatory when the request includes a message body.

```
Host: api.sinay.ai
Content-Type: application/json
Content-Length: 411
```