25 Free Tools to Test Your Website

LambdaTest performs live, interactive cross-browser testing of your public or locally-hosted websites and web apps across 3,000 browsers, devices, and operating systems. Debug in real-time with integrated tools on both desktop and mobile browsers. Free plan for one test and up to 60 minutes a month of real-time browser testing.
Yellow Lab Tools is a free and open-source online test to help speed up heavy web pages. Check performance best practices. Detect problems with HTML, CSS, JavaScript, images, fonts, and more. Provides precise information to fix the detected problems.

Free Tests for Your Site

LambdaTest

Screenshot of W3C Markup Validation Service website.
Screenshot of W3C Markup Validation Service website. Google PageSpeed Insights reports on the performance of a page on mobile and desktop devices and suggests how to improve, providing both lab and field data. Lab data helps debug performance issues, but it may not capture real-world bottlenecks. Field data is useful for capturing real-world user experience but has a limited set of metrics.

After the Deadline checks your text and issues feedback on your writing. Copy and paste your text for contextual spell checking, advanced style checking, and intelligent grammar checking.
UsabilityHub is a remote-user research platform to test your design with real people. Assess the effectiveness of your site’s navigation and content by measuring how users complete tasks using your designs. Free plan with up to three collaborators and tests in up to 2 minutes.
UptimeRobot

Screenshot from Dotcom Monitor home page.
Screenshot from Dotcom Monitor home page. Regularly testing your ecommerce website’s performance will ensure it’s running at an optimal level. There are plenty of free resources available to help.

SERP Racer
Pingdom Website Speed Test analyzes the load speed of a website and identifies why a page is fast, slow, too big, and so on. See how your website conforms to performance recommendations from Google. Pingdom offers a premium service for web speed monitoring.
Dotcom-Monitor

Screenshot of SERP Racer home page.
Screenshot of SERP Racer home page. Xenu’s Link Sleuth checks websites for broken links on images, frames, plugins, backgrounds, local image maps, stylesheets, scripts, and Java applets.

UptimeRobot is an online monitoring application to know when your website is down. The free plan offers 50 monitors for 5-minute checks.
SERP Racer lets you compare scores across key search queries in your niche to understand better the impact of page speed on your business. Enter Google search terms, and run a search to compare site speeds.
Nibbler

Screenshot of Ahrefs Webmaster Tools home page.
Screenshot of Ahrefs Webmaster Tools home page. ClickHeat provides a heatmap of clicks on an HTML page, showing hot and cold click zones. ClickHeat is free and open source.

Uptrends Website Speed Test gives a snapshot of how your desktop or mobile users experience your site. Test in the browser of your choice. Check your Google PageSpeed Insights score, recommended improvements, important page metrics, and page-load progression waterfall report. View important loading events with Google’s Core Web Vitals or W3C navigation timing metrics.
Seorch offers a free test that checks the essential components of SEO, including whether your website meets Google’s quality guidelines. The SEO Check will analyze your website and show errors that prevent a good ranking. Check each URL any number of times.
W3C Markup Validation Service, from World Wide Web Consortium, checks the markup of web documents in HTML, XHTML, SMIL, and MathML, among others. This resource offers tools to validate specific content, such as RSS feeds and CSS, check a website’s level of international friendliness, or find broken links.

Screenshot of Nibbler home page.
Screenshot of Nibbler home page. Web Page Analyzer is a free web speed test with advice on improvement. Enter a URL to calculate page size, composition, and download time. The script computes the size of individual elements and sums up each type.

W3C Markup Validation Service
HubSpot Website Grader evaluates website performance, including page size, page requests, page speed, and more. It also analyzes responsive design, SEO, and security.
KeyCDN Website Speed Test is a full-page speed test from 10 locations worldwide. The results show the requests, content size, and load time. In addition, a waterfall details each asset’s timings and HTTP headers.

Screenshot of HubSpot Grader home page.
Screenshot of HubSpot Grader home page. Dead Link Checker crawls a website, identifying broken links to correct. Target an entire website or a single page. Create an account to check multiple sites or schedule an auto-check.

Browsershots will test your website’s browser compatibility, producing screenshots of your web design in different operating systems and browsers.
Nibbler is a free tool for testing websites. Enter the address of any website, and Nibbler generates a report scoring the website for key areas, including accessibility, SEO, social media, and technology. Nibbler is free but limited to three reports.
Dotcom-Monitor lets you test your website speed in real browsers for free from up to three worldwide locations. Users may select which browser they’d like to run. The test supports Chrome, Firefox, Edge, and mobile browsers on Android, iPhone, and iPad. Free for up to 250 tests per month from five concurrent locations.

UsabilityHub - Five Second Tests website.
UsabilityHub - Five Second Tests website. Juicy Studio Readability Test analyzes the ease of reading level of your text. The algorithms provide only a rough guide but can indicate whether you’ve written content at the right level for the intended audience.

Ahrefs offers free tools to check the search-engine-optimization health of your website. Run a site audit to uncover your website’s technical and on-page issues. Use the Webmaster Tools feature to monitor your overall SEO setup, browse backlink data, and compare your site to competitors in SERPs.
UsabilityHub – Five Second Tests
Five Second Tests, from UsabilityHub, evaluate your site by measuring visitors’ recall and first impressions. Free plan with up to three collaborators and tests for up to 2 minutes.

Screenshot of LambdaTest home page.
Screenshot of LambdaTest home page. HubSpot Website Grader

Here is a list of free tools to test your website. There are tools to measure download speed, monitor user experience, test accessibility, locate broken links, evaluate search engine and browser compatibility, and check mobile friendliness. All of these tools have free plans, and most offer premium options.
GTmetrix provides insights on how well your site loads and recommendations on how to optimize it. GTmetrix can test your pages daily, weekly, or monthly. Set conditions based on page speed and size. Receive email alerts on performance. Analyze the loading of your site from seven global locations.
Inspectlet is a user-testing platform to watch individual visitor behavior on your site with session recording. It includes dynamic heatmaps, A/B testing, form metrics, and error logging. Free for one website and up to 2,500 sessions per month.

Screenshot of UptimeRobot home page.
Screenshot of UptimeRobot home page. Ahrefs Webmaster Tools