HTTP status codes are three-digit response indicators that a server sends after a browser, app, or API makes a request. They show whether the request succeeded, needs another action, or failed. The first digit identifies the response class, while the exact code provides more specific diagnostic context.
HTTP Status Codes
What Are HTTP Status Codes?
HTTP status codes are three-digit response indicators a server sends after a browser, app, or API makes a request. They show whether the request succeeded, needs another action, or failed. The standard codes are maintained in the HTTP status reference.
How HTTP Status Codes Work
- A client requests a web page, file, or API endpoint.
- The server receives and processes the request.
- The server returns a status code, headers, and sometimes a response body.
- The client uses that response to display content, follow a redirect, or report an error.
HTTP Status Code Classes: 1xx to 5xx
| Class | Meaning | Examples |
|---|---|---|
| 1xx | Informational | 100 Continue |
| 2xx | Success | 200 OK, 201 Created, 204 No Content |
| 3xx | Redirection | 301 Moved Permanently |
| 4xx | Client request issue | 400, 401, 403, 404, 409, 429 |
| 5xx | Server failure | 500 Internal Server Error |
How to Read Common HTTP Error Codes
- 400 means the request is invalid or malformed.
- 401 means authentication is required or failed. 403 means access is refused.
- 409 means the request conflicts with the resource's current state.
- 500 means an unexpected server-side failure. A code describes the outcome, not always the root cause.
Checking Status Codes During Testing
Check status codes in a browser's Network panel, API client, server logs, or automated tests. Test expected failures as well as success responses, since a valid delete request may correctly return 204 rather than 200.
HTTP Status Codes in Emergent
Build and test API responses with Emergent. Its workflow supports status-code-aware integrations, testing, and deployment. Explore Emergent Learn, the software glossary, and AI tools for software development.
Frequently Asked Questions
Your Questions, Answered
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What do HTTP status codes beginning with 2xx indicate?
They indicate that the server successfully handled the request. For example, 200 means success, 201 means a resource was created, and 204 means success with no response body.
Which HTTP status code indicates a successful request?
200 OK is the most common successful response, but other 2xx codes can also indicate success depending on the operation.
What is a 204 HTTP status code?
204 No Content means the request succeeded, but the server has no content to return. It is common after a successful delete or update.
What is a 409 HTTP status code?
409 Conflict means the request cannot be completed because it conflicts with the resource's current state, such as editing an outdated version.
How do you check an HTTP status code in Chrome?
Open Chrome Developer Tools, select Network, reload the page or repeat the action, then review the Status column for the request.
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