Rigor features over 40 metrics to help you better understand your web performance data. These metrics will help find, fix, and prevent defects and will give you a greater insight into how to shape your web performance.
First Byte Time: Time from the start of the first request until receiving the first byte of the first non-redirect request. 3xx redirects will increase this time.
DOM Interactive Time: Time until the DOM is fully loaded and processed.
First Paint Time: Time until the browser renders anything other than the default background.
First Contentful Paint Time: Time until the browser first renders any content.
First Meaningful Paint Time: Time until the biggest above-the-fold layout change has happened, and web fonts have loaded.
Start Render Time: Time until the first pixel of content is drawn.
DOM Load Time: Time until the document has loaded, and the initial markup has been parsed. This corresponds to the browser DOMContentLoaded event.
DOM Complete Time: Time until the page and all of its subresources are ready.
First CPU Idle: Time until the page is minimally interactive and will respond to user input in a reasonable amount of time. Click here to learn more about how this metric is calculated.
Time to Interactive: Time until the page is first expected to be usable and will respond to user input quickly. Click here to learn more about how this metric is calculated.
Onload Time: Time until the page has loaded. This corresponds to the browser load event.
Visually Complete Time: Time until all above-the-fold content has finished rendering.
Speed index: A calculated metric that represents how quickly the page renders above-the-fold content. Read more about how it works here.
Fully Loaded Time: Time until there is 1.5 seconds of network inactivity after onload, waiting up to a maximum of 5 seconds. If onload is never reached, it is the time from the start of the first request to the end of the last request to finish. The last request to finish is not always the last request started.
DNS Time: Time required to resolve a host name from the DNS server
TCP Connect Time: Time to create a TCP connection.
SSL Time: Time required for SSL/TLS negotiation.
Send Time: Time required to send HTTP data to the server.
Wait Time: Time from when a request is finished until the time the first byte of the response is received for the first request in a page.
Receive Time: Time required to read the entire response from the server.
Resource and Error Counts
HTML count: Number of requests for HTML documents.
Image count: Number of requests for images.
CSS count: Number of requests for CSS files.
Video count: Number of requests for videos.
Font count: Number of requests for fonts.
Client error count: Number of responses with a status code between 400 and 499.
Connection error count: Number of responses where the status code is 504 or 0 (a browser-aborted request).
Server error count: Number of responses where the status code is 500 or higher (excluding 504).
Error count: Total count of responses with status codes greater than or equal to 400. This is equivalent to the total number of client, connection, and server errors.
Content sizes are calculated using the transfer size (or on-the-wire size) of each request.
HTML size: Total size (bytes) of all HTML content loaded.
Image size: Total size (bytes) of all images loaded.
CSS size: Total size (bytes) of all CSS files loaded.
Video size: Total size (bytes) of all videos loaded.
Font size: Total size (bytes) of all fonts loaded.
Largest Contentful Paint : measures page loading times as perceived by users. The Largest Contentful Paint (LCP) metric reports the render time of the largest content element visible within the viewport.
Total Blocking Time: captures issues that affect interactivity. Optimizations that improve TBT in the lab should also improve FID for your users.
Cumulative Layout Shift: measures page stability. CLS is based on a formula that tallies up how many times the components on the page move or “shift” around while the page is loading. Fewer shifts are better.
Response Time: The Response Time for a single page Real Browser Check is the same as the Load Time. If a Real Browser Check has multiple steps then the Response Time equals the sum of Load Times for each page accessed during the user flow. The Response Time for an Uptime Check is equal to the Server Time.
Uptime: For an Uptime Check, the Uptime metric represents the percentage uptime of an endpoint for a set time frame.
For Real Browser Checks the Uptime percentage represents the percentage of time that the check passed within a set time frame.
Availability: Percentage of total number of successful runs divided by the total amount of runs.