---
title: "Errors"
---

Cal.com uses conventional HTTP response codes to indicate the success or failure of an API request. In general: Codes in the 2xx range indicate success. Codes in the 4xx range indicate an error that failed given the information provided (e.g., a required parameter was omitted, or something else failed, etc.). Codes in the 5xx range indicate an error with Cal.com's servers (these are rare).

<table>
  <thead>
    <tr>
      <th>HTTP</th>
      <th>Status Code</th>
      <th>Summary</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>200</td>
      <td>OK</td>
      <td>Everything worked as expected</td>
    </tr>
    <tr>
      <td>400</td>
      <td>Bad Request</td>
      <td>The request was unacceptable, often due to missing a required parameter</td>
    </tr>
    <tr>
      <td>401</td>
      <td>Unauthorized</td>
      <td>No valid API key provided.</td>
    </tr>
    <tr>
      <td>402</td>
      <td>Request Failed</td>
      <td>The parameters were valid but the request failed.</td>
    </tr>
    <tr>
      <td>403</td>
      <td>Forbidden</td>
      <td>The API key doesn't have permissions to perform the request.</td>
    </tr>
    <tr>
      <td>404</td>
      <td>Not Found</td>
      <td>The requested resource doesn't exist.</td>
    </tr>
    <tr>
      <td>429</td>
      <td>Too Many Requests</td>
      <td>Too many requests hit the API too quickly. We recommend an exponential backoff of your requests.</td>
    </tr>
    <tr>
      <td>500, 502, 503, 504</td>
      <td>erver Errors</td>
      <td>Something went wrong on our servers end. (These are rare.)</td>
    </tr>
  </tbody>
</table>