Awesome Open Source
Awesome Open Source

Checker Services ✅

List of links to the various checkers out there on the web for sites, domains, security etc.

Table of Contents 📖

Accessibility ♿️

URL Description 💳
https://achecker.ca/checker/index.php Checks single HTML pages for conformance with accessibility standards to ensure the content can be accessed by everyone. Free
http://www.dasilva.org.br/ Test sites for accessibility issues (W3C/WAI - WCAG1 and WCAG2 - and E-mag). Free
https://tenon.io/ Test sites for accessibility issues and offer solutions for problems found. Free and paid plans
https://www.toptal.com/designers/colorfilter Checks pages for color accessibility. Free
https://wave.webaim.org/ Gives a detailed report about markup and accessibility concerns including ARIA roles. Provides solutions for problems found. Free

Browser Testing 🌎

URL Description 💳
http://browsershots.org Test websites on many browser, platforms and devices. Free
https://www.browserstack.com/ Test your website for cross browser compatibility on real browsers. Instant access to multiple desktop and mobile browsers. Paid
https://saucelabs.com Test apps and websites in many browsers. Can be integrated in CI workflows. Free trial, free for open source projects, paid
https://testingbot.com Test apps and websites in many browsers. Can be integrated in CI workflows. Free trial, free for open source projects, paid

Cron Jobs ⚡

URL Description 💳
https://cronhub.io/ Painless cron job scheduler & monitoring service. Paid
https://cronless.com/ Online Cron Job Replacement and Monitoring Service. Free
https://deadmanssnitch.com/ Get More Out of Your Cron Jobs. Paid
https://healthchecks.io/ Simple and Effective Cron Job Monitoring. Free

DNS 🌐

URL Description 💳
https://bgp.he.net Check IPs, networks, whois, ASNs, prefixes and more. Free
https://www.digwebinterface.com/ Extensive web interface to dig for doing online DNS / nameserver query. Free and donations welcome
https://dnscheck.pingdom.com/ Enter a domain name to check if its DNS servers are configured correctly. Free
https://dnschecker.org Check the DNS propagation of domains. Free
https://dnsdumpster.com/ Domain research tool that can discover hosts related to a domain. Free
https://dnsspy.io/ Monitor, validate and verify your DNS configurations. Free and paid plans
https://www.dnsstuff.com/tools Multiple DNS tools. Free
https://dnswatch.info/ DNS Lookups & Performance Monitoring. Free
https://www.domainiq.com/tools DNS, IP, MX tools. Free and paid plans
https://whois.domaintools.com/ Reverse whois & IP lookup. Free and paid plans
https://ip6.nl Test if the server supports IPv6. Free
https://ipv6-test.com/validate.php Test if the server supports IPv6. Free
https://www.ipvoid.com Multiple IP address tools. Free
https://mxtoolbox.com/SuperTool.aspx Big collection of useful network tools. Free
https://simpledns.plus/lookup-dg Trace a zone from the root, to debug delegation and whois Free
https://www.tcpiputils.com/ Reverse/history tools for DNS, IP, MX. Free and paid plans
https://toolbox.googleapps.com/apps/dig Easy to use DNS dig tool. Free
https://toolbox.googleapps.com/apps/checkmx Check the MX records of a domain. Free
https://tools.keycdn.com Check for http/2 support and find network related issues. Free
https://www.ultratools.com Big collection of useful network tools. Free
https://www.unlocktheinbox.com/dnstools/mx/ Checks DNS, WHOIS, Blacklists, and more. Free, Paid Plans
https://www.viewdns.info/ View DNS, IP, MX information. Free and paid plans
https://www.nslookup.io/ Global DNS propagation checker. Free

Load Testing 🔥

URL Description 💳
https://loader.io/ Loader.io is a FREE load testing service that allows you to stress test your web-apps & APIs with thousands of concurrent connections. Free and paid plans
https://loadimpact.com/ Load test your website, app or API instantly with up to 1.2 million concurrent users. Get unlimited tests with a free trial. Free and paid plans

Mail Configuration ✉️

URL Description 💳
https://email-checker.net Check emails addresses and lists of email addresses for existence. Free, paid premium plans
https://hunter.io/email-verifier Test the existence of up to 100 email addresses. Free, paid plans
https://www.mail-tester.com/ Test the Spammyness of your Emails. Free
https://mxtoolbox.com/blacklists.aspx The blacklist check will test a mail server IP address against over 100 DNS based email. Free, paid plans
https://www.unlocktheinbox.com/mail-tester/ Email Authentication and Configuration Tester. Free, Paid Plans
https://verify-email.org Verify if an email address and the mailbox behind it exists. Free, paid plans
https://www.verifyemailaddress.org Another email address checker. Free, paid bulk plan
https://tools.verifyemailaddress.io Test if an email address exists. Also provides an API for developers. Free, paid API

Mail Testing ✉️

URL Description 💳
https://www.unlocktheinbox.com/services/inboxtester/ Email Inbox Tester - Check over 20+ destinations. Paid Plans
https://www.campaignmonitor.com Preview emails in over 25 different email clients with the inbox preview feature. Free trial, paid plans
https://www.emailonacid.com Test emails in over 70 email clients, apps and on different platforms. Free trial, paid plans
https://litmus.com/email-testing Test the rendering of emails in over 70 email clients and devices. Free trial, paid plans
https://previewmyemail.com Another provider to test the rendering on many email clients and devices. Paid plans
https://putsmail.com Send and debug emails in three parts (html, plain text, Apple watch). Free

Mobile Friendliness 📱

URL Description 💳
https://developers.google.com/web/tools/lighthouse/ Useful for testing PWA's does mobile friendliness etc but not exclusively mobile. Free
https://search.google.com/search-console/mobile-usability Test how easily a visitor can use your page on a mobile device. Just enter a page URL to see how your page scores. Free

Security 🔒

URL Description 💳
https://www.checkbot.io/ Browser extension that checks multiple pages at once for web security best practices. Finds HTTPS mixed content issues, insecure password forms and more. Free and paid plans
https://crt.sh Get an overview and information of assigned TLS certificates. Free
https://csp-evaluator.withgoogle.com Validate and check the CSP for weaknesses and security issues. Free
https://hackertarget.com This service provides multiple tools to check websites for vulnerabilities. Free and paid plans
https://www.hardenize.com/ Harden your server's security. Free
https://hstspreload.org/ Check if a domain is on the HSTS preload list in browsers and submit them to the list. Free
https://httpschecker.net/ Track down HTTPS mixed content issues. Free and paid plans
https://www.isithacked.com Check if there are any signs that a website is hacked. Free
https://www.magereport.com MageReport checks if a Magento instance is outdated and if all security patches are installed. Free
https://observatory.mozilla.org/ Observatory by Mozilla is a project designed to help developers, system administrators, and security professionals configure their sites safely and securely. Free
https://report-uri.io/home/tools Multiple useful tools for CSP, HPKP, SRI, headers and certificates. Free
https://securityheaders.io/ Scott Helme built securityheaders.io after deploying security headers like CSP and HSTS to his own site. He wanted a quick and easy way to check if other sites were using these headers and he figured he'd turn it into a useful tool for everyone to use! Free
https://sshcheck.com Check the SSH configuration of servers. Free
https://www.ssllabs.com/ssltest/ This free online service performs a deep analysis of the configuration of any SSL web server on the public Internet. Free
https://tls.imirhil.fr/ Test the strength of the available ciphers which can be used with HTTPS or SSH. Free

SEO 📈

URL Description 💳
https://www.checkbot.io/ Browser extension that checks multiple pages at once for SEO best practices. Finds duplicate content, broken links, unfriendly URL names and more. Free and paid plans
https://insites.com/ Test your websites for everything. Check spelling, broken links, SEO, accessibility and more. Paid
https://nibbler.silktide.com/ Nibbler is a free tool for testing websites. Enter the address of any website and Nibbler will give you a report scoring the website out of 10 for key areas, including accessibility, SEO, social media and technology. Free and paid plans
https://search.google.com/structured-data/testing-tool/u/0/ Evaluate your structured data (rich snippets) markup for errors or warnings. Free
https://seomator.com SEO Audit Tool and website crawler for SEO performance improving with How-to-Fix tips. Paid

Technology Used 🖥

URL Description 💳
https://builtwith.com/ Find out what websites are Built With. Free and paid plans

Uptime Monitoring 📉

URL Description 💳
https://www.freshworks.com/website-monitoring/ 50 monitors, 1 min intervals, 5 public status pages free. Free and paid plans
https://tryhexadecimal.com No-nonsense website monitoring and status page service. Paid
https://ohdear.app/ 2 sites, 5 euro, uptime, certificate monitoring, mixed content scanning and more. Paid only
https://www.statuscake.com/ 10 monitors, 5 min intervals, branded public reporting free. Free and paid plans
https://uptimerobot.com/ 50 monitors, 5 min intervals, 2 months of logs free. Free and paid plans

URL Analysis 🌐

URL Description 💳
https://urlscan.io Find out what happens when a URL is accessed. Free

Validation 👌

URL Description 💳
https://validator.w3.org/unicorn/ Checks for proper HTML and CSS markup as well as broken links. Free
https://www.zerobounce.com/ Checks to see if the email address is valid. Free, Paid plans

Website Performance 🚀

URL Description 💳
https://www.checkbot.io/ Browser extension that checks multiple pages at once for performance best practices. Finds unminified resources, redirect chains, render-blocking JavaScript and more. Free and paid plans
https://developers.google.com/speed/pagespeed/insights/ PageSpeed Insights analyzes the content of a web page, then generates suggestions to make that page faster. Free
https://gtmetrix.com/ GTmetrix is a free tool that analyzes your page's speed performance. Using PageSpeed and YSlow, GTmetrix generates scores for your pages and offers actionable recommendations on how to fix them. Free and paid plans
http://www.monitis.com/pageload Simple page load test from 3 continents. Free
https://pageweight.imgix.com/ See how images affect your page speed. Free
https://testmysite.withgoogle.com Checks websites for performance issues and provides reports. Free
https://toolbox.googleapps.com/apps/har_analyzer Analyze the performance with a HAR file. Free
https://tools.pingdom.com/ Enter a URL to test the load time of that page, analyze it and find bottlenecks. Free and paid plans
https://www.uptrends.com/tools/website-speed-test Check the performance from 30+ free and 160+ paid checkpoints. Free, paid plans
https://www.webpagetest.org Website performance test tools with many options. Free
https://yellowlab.tools/ Online test to help speeding up heavy web pages. Free

Contributing ✍️

This started as a small personal project.

Although this project is small, openness and inclusivity are taken seriously. To that end a code of conduct (listed in the contributing guide) has been adopted.

Contributor Guide


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