Tool Overview

This tool analyzes a website URL and shows performance metrics and improvement suggestions. You enter a web address and choose mobile or desktop. The tool runs a performance check and returns a score, Core Web Vitals metrics, and a list of actions you can take to improve speed and user experience.

Slow or janky pages hurt users and can affect how a site ranks in search. Measuring performance by hand is hard. You need to know what to measure and how to read the numbers. This tool runs the analysis for you and shows the main metrics and clear next steps. You can switch between a simple view and a technical view depending on your role.

The tool is for site owners, marketers, and developers who want to see how a page performs and what to fix first. You can use it with little technical knowledge if you use the simple descriptions. Developers can turn on the technical view to see effort, metric, and savings for each action.

Background & Concept Explanation

Web performance is how fast a page loads and how responsive it feels. Search engines and users care about it. Several metrics describe different parts of the experience: how soon content appears, how soon the main content is visible, how stable the layout is, how quickly the page responds to input, and how fast the server responds. A related operation involves referencing the ASCII chart as part of a similar workflow.

Core Web Vitals are a set of metrics that many tools and search engines use. First Contentful Paint (FCP) is when the first text or image appears. Largest Contentful Paint (LCP) is when the main content has loaded. Cumulative Layout Shift (CLS) measures how much the page jumps while loading. Interaction to Next Paint (INP) measures how quickly the page responds to user input. Time to First Byte (TTFB) measures how long it takes for the server to start sending data. This tool shows these metrics with a value, a score, and a short description.

An analysis service loads the page in a controlled environment and records these metrics. The tool sends your URL to a backend that runs that analysis and returns the results. You do not run the test yourself. The analysis can take half a minute or more. There are limits on how often you can run it so the service is not overloaded.

After the analysis you get a list of recommended actions. Each action has a title, a simple or technical description, an impact level, and which metric it affects. You can sort the list by business impact (what matters most for users and search) or by score tuning (what can improve the number most). The tool can also generate an optional AI-written guide tailored to your result. For adjacent tasks, looking up the ASCII table addresses a complementary step.

Key Features

• URL analysis. You enter a full web address and the tool checks it. You can type the URL with or without https; the tool adds https if needed. Only http and https URLs are accepted. This lets you test any public page you can open in a browser.
• Mobile and desktop. You choose whether to analyze the page as mobile or desktop. The result depends on that choice because performance and layout differ by device. This matters when you optimize for phones or for large screens.
• Overall score and health badge. The tool shows a single performance score and a pass or fail style message. You see at a glance whether the page is in good shape or needs work. The score and message come from the analysis service.
• Core metrics. The tool displays metrics such as FCP, LCP, CLS, INP, and TTFB. Each metric has a value, a unit, a score from zero to one, and a short description. A bar or color shows how good the score is. This helps you see which areas are weak.
• Priority actions. The tool lists recommended improvements. Each item has a title, a description, an impact level (high, medium, low), and the metric it affects. In technical mode you also see effort and potential time savings. You can use this list to decide what to fix first.
• Focus mode. You can sort the actions by business impact (Core Web Vitals and user value first) or by score tuning (what improves the score most). This lets you focus on what matters for your goal.
• Technical mode. You can switch between non-technical and developer view. Non-technical view shows plain-language descriptions. Developer view shows technical descriptions plus effort, metric, and savings. This helps both managers and developers use the same report.
• Optional AI optimization guide. After you have a result you can ask for an AI-generated guide. The tool sends your score, failing metrics, and action list to a backend and returns a short written guide. The guide is optional and requires network access.
• Re-analyze and reset. You can run the analysis again on the same URL or start over and enter a new URL. A cooldown applies between requests so you cannot overload the service. If the service returns a rate limit error you must wait before trying again.

Common Use Cases

Checking a live site. You launch a new page or redesign and want to see how it performs. You enter the URL, pick mobile or desktop, and run the analysis. You get the score and metrics and can share the result with your team or client.

Finding what to fix first. The score is low and you want to know where to start. You open the priority actions list and sort by business impact. You fix the high-impact items that affect LCP, CLS, or INP first, then re-run the analysis to see the change.

Reporting to non-technical stakeholders. You switch to non-technical mode and focus on business impact. The descriptions are in plain language. You use the overall score and health badge to show status and the action list to show next steps. When working with related formats, testing responsive layouts can be a useful part of the process.

Developer optimization. You turn on technical mode and sort by score tuning. You see effort and savings per action. You pick quick wins (low effort, good savings) first, then tackle harder items. You use the metric labels to tie each action to FCP, LCP, CLS, INP, or TTFB.

Comparing mobile and desktop. You run the analysis once for mobile and once for desktop. You compare the scores and metrics to see if one experience is worse and needs more work.

How to Use This Tool (Step-by-Step)

1. Open the tool. You will see a URL input and device toggle (Mobile, Desktop).
2. Enter the URL. Type the full address of the page you want to analyze, for example https://example.com or example.com. The tool will add https if you leave out the protocol.
3. Choose mobile or desktop. Click Mobile or Desktop to set how the page will be tested. The result depends on this choice.
4. Click Analyze. The tool sends the URL to the backend and runs the performance check. Wait 30 to 60 seconds or more. Do not close the page. If you get an error, read the message; you may need to wait before trying again.
5. View the result. You will see the overall score, health badge, URL, and device. Below that you will see Core Metrics (FCP, LCP, CLS, INP, TTFB) and Priority Actions.
6. Read the metrics. Each metric shows a value, unit, score, and description. Use the score and bar to see which metrics are good or bad.
7. Read the actions. Each action has a title, description, impact, and metric. Use the focus toggle to sort by Business Impact or Score Tuning. Use the Technical Mode toggle to switch between simple and developer descriptions.
8. Generate the AI guide if you want. Scroll to the AI Optimization Guide section and click Generate. Wait for the text. This step is optional and uses the network.
9. To run again on the same URL, click Re-analyze. To start over with a new URL, click the reset (rotate) button to clear the result and show the input form again. Note: you must wait a short time between analyses; if you hit a rate limit you must wait longer.

Reference: Core Metrics Shown by the Tool

Each metric is shown with a value, a score, and a short description. The tool uses these to build the priority actions list. In some workflows, decoding JSON Web Tokens is a relevant follow-up operation.

Tips, Limitations & Best Practices

The analysis runs on a server and can take 30 to 60 seconds or more. Do not assume the tool is broken if it takes a minute. If the request times out, the page may be very slow or the service may be busy; try again later.

There is a minimum wait between analyses (about 30 seconds). If you send too many requests you may get a rate limit error and a cooldown of several minutes. Use the tool for single URLs or occasional checks, not for bulk or automated testing.

The URL must be public and reachable by the analysis service. Pages that require login, block automated access, or are behind a firewall may fail or give incomplete results. Use a public URL for the page you want to test. For related processing needs, checking your IP address handles a complementary task.

Results can vary between runs. Network and server conditions change. Use the result as a snapshot and re-run after you make changes to see if things improved. Do not expect the exact same numbers every time.

The overall score and metrics come from the analysis service, not from this tool. The tool only displays them. For details on how each metric is defined and scored, refer to the documentation of the underlying service.

The AI guide is generated by a backend using your result. It is optional and may be subject to usage limits. If generation fails you still have the score, metrics, and action list to work from.

Use mobile analysis when most of your users are on phones. Use desktop when you care about large screens. Run both if you need to compare and optimize for each.