Load Summary
A quick summary of the page load, including TTFB, Fully Loaded time, and total transferred size.
Documentation
SpeedCheck Help
This page explains the terms used in reports, performance metrics, browser timings, waterfall charts, nodes, and test settings.
Report Summary
Performance cards use four rating levels: Good, OK, Long, and Poor. Administrators can change the three numeric boundaries for each visible metric from Admin Settings.
Page Details
A quick resource summary for the report, showing FCP, the number of recorded page elements, and the slowest loaded element.
Estimated Values
Measured values come from Lighthouse, Navigation Timing, HAR page timings, or observed long-task/layout-shift entries. When Lighthouse fields are missing, SpeedCheck uses HAR request timing to estimate render readiness, early visual completion, interactivity, and blocking windows; these values are marked as Estimated.
Test Server Location
The node location used for the test. Location codes use the cc-datacenter format, such as ir-asiatech, and the country code controls the flag.
Total Download Size
The total transferred size for all recorded requests in the test. It helps compare page weight across test runs.
Total Page Elements
The total number of recorded requests and resources in the waterfall, including HTML, CSS, JavaScript, images, fonts, API calls, and other assets.
Slowest Element Load
The longest single request duration found in the waterfall. It helps identify the resource that took the most time to load.
Performance Metrics
These metrics primarily come from Lighthouse performance data. HAR page timings, waterfall request timing, browser paint entries, long tasks, and layout-shift entries are used as fallbacks when direct Lighthouse values are not present.
First Contentful Paint (FCP)
How quickly the browser paints the first text, image, SVG, or canvas content. If no browser paint timing is present, SpeedCheck estimates it from the final HTML response, render-blocking CSS, and a small render allowance.
Time to Interactive (TTI)
How long it takes for the page to become reliably interactive. Direct Lighthouse TTI is preferred; if HAR does not include long-task data, SpeedCheck extends FCP by the largest estimated JavaScript task.
Speed Index
How quickly visible content appears during load. Lighthouse calculates this from visual frames; when frames are not available, SpeedCheck estimates it from the FCP-to-LCP visual window.
Total Blocking Time (TBT)
The total time where long JavaScript tasks block the main thread after FCP. Direct Lighthouse or long-task data is preferred; otherwise SpeedCheck estimates JavaScript task cost from HAR script payloads and sums only the part above 50ms per task.
Largest Contentful Paint (LCP)
How long it takes for the largest visible content element, often a hero image or main heading, to render. Lower is better.
Cumulative Layout Shift (CLS)
How much visible layout moves unexpectedly while the page loads. Lower is better; without browser layout-shift entries, SpeedCheck displays an Estimated zero from the HAR-only fallback.
Browser Timings
Browser Timings are read from Navigation Timing data and HAR page/request timings. The main document request is used for connection, backend, and TTFB values.
Redirect Duration
The time spent following redirects before the final page request starts.
Connection Duration
The time spent establishing the network connection, including TCP and sometimes TLS setup.
Backend Duration
The time from sending the request until the server begins sending the response. This helps reveal slow server processing.
Time to First Byte (TTFB)
The time until the first byte of the main document response is received. It includes network and server response time.
First Paint
The first moment the browser paints anything that is visually different from the default background.
DOM Interactive Time
The point where the browser has parsed the document enough for scripts to begin interacting with the DOM.
DOM Content Loaded Time
The time when the initial HTML is parsed and deferred scripts have run, without waiting for images and every subresource.
Onload Time
The browser load event timing. It usually fires after the document and dependent resources have loaded.
Fully Loaded Time
The final observed page load milestone in the report, based on browser timing and waterfall activity.
Waterfall Chart
Waterfall
A request-by-request view of the page load. It shows when each request started, how long it took, and which phase consumed time.
URL
The requested resource path or URL, such as the main document, CSS file, JavaScript file, image, font, video, or API call.
Status
The HTTP status code returned by the server. Failed requests are highlighted because they can affect page behavior.
Type
The request method and resource category, for example GET HTML, GET CSS, GET JS, image, font, video, or XHR.
Domain
The hostname that served the request. This helps identify third-party services and external dependencies.
Size
The transferred or encoded response size when available. Smaller assets usually load faster and consume less bandwidth.
Timeline
The visual timing bar for each request. Colored segments show the different network phases of that request.
Blocking
Time spent before the browser can start the request. It can include queueing and connection slot delays.
DNS Lookup
Time spent resolving a domain name to an IP address.
Connecting
Time spent opening the network connection to the server.
SSL
Time spent negotiating TLS for HTTPS requests.
Sending
Time spent sending the HTTP request to the server.
Waiting
Time spent waiting for the server to start responding after the request is sent.
Receiving
Time spent downloading the response from the server.
Download HAR
Downloads the HTTP Archive file for deeper debugging in tools that support HAR inspection.
Request Details
Headers
Request and response metadata, such as content type, cache headers, server headers, cookies, and browser request headers.
Parameters
Query string values included in the URL.
Post
Data sent in the request body for POST or similar requests, when available in the captured data.
Response
Information about the server response, such as status, type, size, redirect target, and body preview if available.
Image from URL
A preview of an image request directly from its URL, when the resource type is image.
Video from URL
A preview player for a video request, when the resource type is video.
Initiator
The script, parser, or browser action that caused a request to start. This helps trace why a resource was loaded.
Test Settings
Browser
The browser engine used to run the test, such as Chromium, Firefox, or WebKit when supported by the plan and node.
Network Profile
The simulated connection settings used during the test, such as download speed, upload speed, and latency.
Wait Until
The browser event used to decide when the page load step is complete, such as DOMContentLoaded, load, or network idle.
Daily Limit
The number of tests a guest or user can run per day. Admin settings and user plans can change this limit.
Nodes
Node
A remote worker server that runs browser tests and sends screenshots, HAR data, waterfall data, and result JSON back to the master app.
Location Code
The node location format is cc-datacenter. For example, ir-asiatech means country Iran and datacenter Asiatech.
Node Status
The latest health check result from the node. OK means the node responded to health and status endpoints.
Node Queue
The current running and queued job counts for a node. The master uses this to avoid overloading nodes.
Plan
A user package that can define daily limits, retention days, allowed browsers, and allowed node tags.