HTTP Header Checker
Display the HTTP response headers sent by a web server
Features
Retrieve HTTP headers
Retrieve the response headers of a specified URL on the server side and display them
Trace the redirect path
Follow 3xx redirects to the final destination and check the headers of each hop
Determine the status code
Color-code 2xx/3xx/4xx/5xx to grasp the response state at a glance
Copy headers
Copy the name and value of each item to the clipboard with one click
How to use
Enter a URL
Enter the URL of the page you want to check in the input field; the scheme can be omitted
Retrieve with the check button
Press the check button and the server retrieves and displays the headers
Check the headers and path
Check the status code and each header; redirects are shown in path order
Use cases
Checking cache settings
Verify cache behavior from Cache-Control and Expires
Inspecting security settings
Check whether defensive headers such as HSTS and CSP are present
Investigating redirects
Follow the destinations and number of hops to find loops or excessive redirects
Investigating server information
Infer the running environment and configuration from Server and X-Powered-By
Checking responses before release
Check status codes and configuration mistakes in advance just before release
Fundamentals
What are HTTP Response Headers
Response headers are supplementary information that servers return along with the page body, including cache handling, content type, server details, and redirect destinations.
Common Status Codes
- 200：200 is a status code indicating that the request was successful and content was returned normally.
- 301・302：301 and 302 are codes indicating that a page has moved to a different URL, with 301 meaning permanent and 302 meaning temporary redirection.
- 404・500：404 is a code indicating that a page does not exist, and 500 indicates a server internal error. These are the first values to check as starting points for investigating issues.
Safety and Privacy
Server-side processing
Input is processed on the server; only information necessary for the inquiry is sent.
Temporary processing only
For retrieving HTTP headers, temporary processing occurs on the server, then data is discarded after results are returned.
Communications encrypted with HTTPS
All sent and received data is encrypted by TLS and cannot be read by third parties.
No transmission to third parties
Input content is not sent to external services such as ad networks or trackers.
Sent only to the target server
Accesses the entered URL to retrieve headers and sends only to the target server
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RAKKOTOOLS is free to use!
Available free of charge for individuals and corporations, commercial and non-commercial use alike.No prior permission or usage application is required. Feel free to use it in various situations.
Use in streaming and videos
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Use in schools, work, and events
Can be used in various situations such as classes, team division, internal work, and events.
Introduction on Web, books, and SNS
Feel free to introduce it as a useful tool on web media, books, SNS, and other platforms.
Commercial use
Can be used for commercial purposes such as research, calculation, processing, and conversion in business and production.
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If using in streaming and videos
Link to RAKKOTOOLS in the description, or Mention or display that you are using RAKKOTOOLS in the stream or video.
Credit example for the description
Usage guidelinesYou are free to use it for normal purposes. However, use for purposes that violate laws, infringe on third-party rights, impose significant load on the service, or otherwise interfere with service operation is prohibited.
We do not guarantee the accuracy or completeness of information and calculation results obtained from each tool.
This notice is a translation of the original Japanese text. If there is any discrepancy between the translation and the original, the Japanese original takes precedence.