---
updatedAt: 2025-06-09T23:20:07.000Z
agentTools:
projectIndex: https://developers.acuityscheduling.com/llms.txt
---
# API Errors
Here's what can go wrong in Acuity's API, and how to fix it. As always, feel free to reach out to developers@acuityscheduling.com if you run into a problem you're having trouble fixing!
## General API Errors
These are the errors we all know and love. They're errors that can happen in most web applications, and they should be straight forward to solve.
| Status | Error | Response | Description |
| ------ | --------------------- | ---------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| 400 | Bad Request | `{"status_code": 400, "message": "Expected a JSON object.", "error": "bad_request"}` | The request requires a JSON body, but we couldn't parse it. Double check that you're sending a request body and that the body is valid JSON. |
| 401 | Unauthorized | `{"status_code": 401, "message": "Unauthorized", "error": "unauthorized" }` | We don't know who you are! Either the request didn't include authentication or the authentication wasn't valid. Double check the user ID and API key, or head to [Getting Started](https://developers.acuityscheduling.com/docs/quick-start) for an example. |
| 403 | Forbidden | `{ "status_code": 403, "message": "Forbidden", "error": "forbidden" }` | The request included authentication and we know who you are, but you don't have access to the resource. Eg. the calendar or appointment type belongs to another user. |
| 404 | Not Found | ``{ "status_code": 404, "message": "Not Found. Did you mean `/appointments/{id:number}`?", "error": "not_found" }`` | The requested resource could not be found. Fat fingers happen, so if it looks like a typo we'll do our best to suggest the correct endpoint. Also double check URI IDs, in case the resource legitimately does not exist. |
| 405 | Method Not Allowed | `{ "status_code": 405, "message": "Method Not Allowed", "error": "method_not_allowed" }` | The resource exists but the HTTP method is not supported. Not all of our endpoints support the same methods. [Check our docs](https://developers.acuityscheduling.com/docs/get-appointments) for the methods which are supported. |
| 429 | Too Many Requests | `{"status_code": 429,"error": "too_many_requests","message": "Rate limit reached. Limit 10req/s and 20 concurrent connections."}` | Woah there! Our API is currently rate limited to 10 requests a second and 20 concurrent connections from an IP. |
| 500 | Internal Server Error | `{ "status_code": 500, "message": "Internal Server Error", "error":"internal_server_error" }` | Something unexpected happened. These errors should not happen, but when they do we'll get notified and be on the case quickly. Feel free to reach out to us at . |
## Specific API Errors
Many of our endpoints return specific errors related to that endpoint. These errors will will do their best to include a descriptive message about what went wrong. The error response body looks like this:
```json
{
"status_code": 400,
"error": "invalid_name",
"message": "Can not clear the field \"firstName\"."
}
```
| Status | Error | Response | Description |
| ------ | -------------------- | ---------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| 400 | Bad Request | `{"status_code": 400, "message": "Can not clear the field \"firstName\".", "error": "invalid_name"}` | General validation errors such as unexpected values or missing required fields will generate 400 errors. We'll give a descriptive message about what went wrong to help you resolve it. |
| 422 | Unprocessable Entity | `{"status_code": 422, "message": "End is before start.", "error": "invalid_time"}` | Left over from before [RFC 7231](https://tools.ietf.org/html/rfc7231) opened up the description of the 400 status code, our `POST /blocks` endpoint returns 422 error on time validation errors. |
Attributed to Rogério Vicente & Tonomi - [https://http.cat/](https://http.cat/)