Skip to main content

System limitations on KurocoEdge

Potential Major Impact

  • You need to have ownership of the domain you want to use
  • The IP address of the source is set to X-forwarded-for
  • Maximum response timeout of 60 seconds
  • Responses from KurocoEdge are always in UTF-8
  • HTTPS is used in principle. Requests via HTTP are redirected to HTTPS
  • If the HTML is broken, the CSS Selector may not work properly

List of responses

Unable to change the DNS records of the applied domainCannot apply KurocoEdgeNot available for use
IP restriction is applied at the backend serverAccess to the backend server comes from the IP address of KurocoEdgeUse X-forwarded-for, apply IP address restriction in KurocoEdge
There are pages that take more than 60 seconds to respondResponse times out and an error occursProcess the page on a domain that does not use KurocoEdge
Pages are displayed in SJIS or EUC-JPPages are displayed after encoding in UTF-8Change the encoding description in HTML in KurocoEdge
There are pages that only operate on HTTPRedirected to HTTPS but not displayed properlyThe relevant page cannot be used
There are pages with broken HTMLCSS selector are not functioning properlySubstitute with text replacements

Potentially Affected Areas

  • For files with png/jpg/jpeg/gif extensions when caching setting is enabled, responses to clients that can use webp are automatically converted to webp
  • If cache is enabled for files with png/jpg/jpeg/gif extensions and the parameters for automatic image conversion are automatically enabled
  • Only TLS1.2/TLS1.3 can be used
  • If the cache settings are not set in the rules, cache-control: private, no-store is automatically set in the response header
  • In the following cases, gzip/Brotli compressed responses are automatically applied
    • If you are trying to use KurocoEdge in conjunction with another Fastly service you are already using, Service chaining will be applied, but you may encounter errors with Loop detection, etc. In this case, please contact support
File extensions:  
css js html eot ico otf ttf json svg

Content types:
text/html application/x-javascript text/css application/javascript text/javascript application/json application/ application/x-font-opentype application/x-font-truetype application/x-font-ttf application/xml font/eot font/opentype font/otf image/svg+xml image/ text/plain text/xml
  • The response headers from the following backend servers will be automatically converted as follows. However, it is possible to reset them using rules
Original Header NameConverted Header NameDescription
x-cache-hitsx-kuroco-backend-x-cache-hitsNumber of cache hits
x-cachex-kuroco-backend-x-cacheWhether the cache was hit or not, etc.
last-modifiedx-kuroco-backend-last-modifiedLast modified date of the content
agex-kuroco-backend-ageCache lifespan (in seconds)
cache-controlx-kuroco-backend-cache-controlCache settings such as the validity period
etagx-kuroco-backend-etagIdentifier for identifying the content


If you have any other questions, please contact us or check out Our Discord Community.