> For the complete documentation index, see [llms.txt](https://developer.acquire.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.acquire.io/rest-apis/introduction/interrelated.md).
# Request Types, Permissions, Errors, & Limits
### CREATING REQUESTS
According to RESTful structure, Acquire implements the following HTTP verbs:\
\
`GET -` Read entity\
`POST -` Create new entity\
`PUT -` Modify existing entity\
`DELETE -` Remove entity
## PERMISSIONS
To request any API endpoint, you will need a valid API key with the related access permissions.
Learn more about obtaining an API key and access permissions in the [Authorization](https://developer.acquire.io/rest-apis/authorization) section.
## Errors
Errors are returned using standard HTTP error codes.
In general, the list of error codes includes:
| Code | Explanation |
| ---- | ------------------------------ |
| 2xx | Success |
| 4xx | Bad request sent to the server |
| 5xx | Server-side error |
### STATUS CODES
`200 OK` Successful request.\
`400 Bad Request` Returns JSON with the error message.\
`401 Unauthorized` Couldn’t authenticate your request.\
`403 Forbidden` Invalid request.\
`404 Not Found` No such object.\
`500 Internal Server Error` Something went wrong.\
`503 Service Unavailable` Service is down for maintenance.
| Types | Code | Explanation |
| ------------------------------ | ---- | -------------------------------------- |
| `ERROR_INVALID_INPUT` | 400 | Invalid request |
| `ERROR_RECORD_NOT_FOUND` | 400 | No credentials in the request body |
| `ERROR_DUPLICATE_RECORD_FOUND` | 400 | Already exists |
| `ERROR_UNAUTHORIZED` | 401 | Missing, incorrect, or invalid API Key |
| `ERROR_UNAUTHORIZED_ACCESS` | 403 | Invalid request |
| `ERROR_SERVER_ERROR` | 500 | Internal server error |
## API Limit
There are no API consumption limits.