Error codes
- 4xx codes: most of the time URL is not found due to broken links, or forbidden.
- 5xx codes: server errors.
- TCP errors: network error.
- Malformed URLs: the URL can not be fetched because of syntax problems.
- DNS resolution failed : the hostname of the URL is unknown
- Connection failed : the web server or the network might be down or too busy
- Request timeout : the web server could not reply before the specified delay (surely because it is too busy).
Loading
- Slowest time to first byte (> 250 ms)
- Slowest file loading time (> 250 ms)
- Pages requiring most http requests
- Slowest DOMContent events (> 500 ms)
- Slowest onLoad events (> 2 s)
Notes: load time is the time to load the HTML code. Download size may be different from Kilobytes for compressed pages. Javascript rendering is required to get DOMContent events and onLoad events values.