The following serves as an index of a range of web-based tools, browser extensions, command-line tools, scripts, and bookmarklets. It is not complete; it might lack some important tools; but many tools come with my endorsement, and the promise to also serve others well.
(By the way, my UITest.com site is a hub for web-based testing tools, generators, and anything else web-based that’s useful for web developers and designers. You can find many of the tools listed in this book and more there.)
Accessibility Analysis (Gecko browser extension) (https://mzl.la/2cqOkkH)
Accessibility Check (AATT; Automated; command-line tool) (https://github.com/paypal/AATT)
Accessibility Check (FAE) (http://fae20.cita.illinois.edu/)
Accessibility Check (WAEX) (http://www.it.uc3m.es/vlc/waex.html)
Accessibility Check (WAVE 3.0) (http://wave.webaim.org/)
Accessibility Developer Tools (WebKit browser extension) (http://bit.ly/2cI92xl)
Accessibility, HTML, and Link Check (WebKit and Gecko browser extension) (https://www.totalvalidator.com/)
Accessibility Linter (http://accesslint.com/)
Accessibility Visualization (script) (https://github.com/Khan/tota11y)
AES Encrypter (https://www.infoencrypt.com/)
Android Emulators (http://www.manymo.com/emulators)
ARIA Validator (WebKit browser extension) (http://bit.ly/2cqQccO)
Availability Check (CurrentlyDown.com) (http://www.currentlydown.com/)
Availability Check (Is It Down Right Now) (http://www.isitdownrightnow.com/)
Availability Check (Regional; InternetSupervision.com) (http://bit.ly/2cRSwiS)
Availability Check (Regional; Site24x7) (http://bit.ly/2caFmL3)
Bandwidth Speed Test (http://www.bandwidthplace.com/)
Blowfish Hash Generator (http://hash.online-convert.com/blowfish-generator)
Browser Screenshots (Windows, Mac OS, Android, iOS) (http://www.browserstack.com/screenshots)
Browser Screenshots (Windows, Mac OS, Linux) (http://browsershots.org/)
Browser Test Automation (Sahi; browser extension) (http://sahipro.com/docs/introduction/)
Browser Test Automation (Selenium; browser extension) (http://bit.ly/1JVDVIY)
Browser Test Automation (Squish) (https://www.froglogic.com/)
Browser Test Automation (Watir; browser extension) (https://watirwebdriver.com/)
CMS Detector (http://guess.scritch.org/)
Code Formatter (Code Beautifier) (https://ctrlq.org/beautifier/)
Code Formatter (Pretty Printer) (http://www.prettyprinter.de/)
“Cognitive Walkthrough for the Web” Tools (http://bit.ly/2cBu5ED)
Colorblind Web Page Filter (http://colorfilter.wickline.org/)
Color Contrast Analysis (Jonathan Snook) (http://bit.ly/2cmljIc)
Color Contrast Analysis (WCAG Contrast Checker; Gecko browser extension) (https://mzl.la/2cmVY1A)
Color Contrast Analysis (WebAIM) (http://webaim.org/resources/contrastchecker/)
Color Deficit Emulation (http://www.vischeck.com/vischeck/vischeckURL.php)
Color Selector (http://bit.ly/2cGbe9P)
Cookie Editor (WebKit browser extension) (http://bit.ly/2ctdnGQ)
CSR Decoder (https://www.sslshopper.com/csr-decoder.html)
CSS Accessibility Analysis (http://bit.ly/2cWIADz)
CSS Analysis (http://cssstats.com/)
CSS Compressor (http://hell.meiert.org/aux/compress/css/gui/)
CSS Formatter (CSS Portal) (http://bit.ly/2cl8H2K)
CSS Formatter (Lonnie Best) (http://bit.ly/2cKq91z)
CSS Linter (http://csslint.net/)
CSS Optimizer and Formatter (CSS Beautifier) (http://bit.ly/2ccoJ1v)
CSS Optimizer and Formatter (CSScomb) (http://csscomb.com/online/)
CSS Validator (W3C) (http://jigsaw.w3.org/css-validator/)
CSS Validator (WDG) (http://www.htmlhelp.com/tools/csscheck/)
DAML Validator (http://www.daml.org/validator/)
Design Responsiveness Test (http://responsivepx.com/)
DNS Analysis (https://cloudmonitor.ca.com/en/dnstool.php)
DNS Propagation Check (https://www.whatsmydns.net/)
Download Time Calculator (http://www.whytehouse.com/opener.html)
Edge Compatibility Test (http://doesitworkonedge.com/)
Email Blacklist Check (http://mxtoolbox.com/blacklists.aspx)
Font Combinator (http://font-combinator.com/)
Font Comparison (http://www.typetester.org/)
Font Determiner (WhatFont; WebKit browser extension) (http://bit.ly/2cUTmY6)
Font Determiner (WhatTheFont) (http://www.myfonts.com/WhatTheFont/)
Font Fallback Determiner (bookmarklet) (http://ffffallback.com/)
FTP Server Test (https://www.dotcom-tools.com/ftp-server-test.aspx)
Golden Ratio Typography Calculator (http://www.pearsonified.com/typography/)
Google Webmaster Guidelines Check (https://varvy.com/)
hCalendar Generator (http://microformats.org/code/hcalendar/creator)
hCard Generator (http://microformats.org/code/hcard/creator)
hCard Validator (http://hcard.geekhood.net/)
.htaccess Validator (http://bit.ly/2cqOs3D)
HTML Compatibility Check for XHTML (http://qa-dev.w3.org/appc/)
HTML Compressor (http://htmlcompressor.com/compressor/)
HTML Compressor (html-minifier) (http://bit.ly/2cUUjQ8)
HTML Formatter (http://bit.ly/2cpa6qj)
HTML, CSS, and Conformance Validator (http://validator.w3.org/unicorn/)
HTML, CSS, and JS Formatter (https://www.dirtymarkup.com/)
HTML Outline Extractor (http://gsnedders.html5.org/outliner/)
HTML Validator (W3C) (http://validator.w3.org/)
HTML Validator (WDG) (http://bit.ly/2cBBH9X)
HTML 5 Validator (http://html5.validator.nu/)
HTTP Header Editor (Request Maker; WebKit browser extension) (http://bit.ly/2cWGNOH)
HTTP Header Editor (Tamper Data; Gecko browser extension) (https://mzl.la/2coxG7D)
HTTP Header Test (http://www.rexswain.com/httpview.html)
HTTP Header Test (Advanced) (http://bit.ly/2ctczOY)
Image and Link Analysis (http://bit.ly/2cKgyaV)
Internationalization Check (http://bit.ly/2ccmF9Q)
Internet Explorer Viewer (IE NetRenderer) (http://netrenderer.com/)
Internet Explorer Viewer (URL2PNG) (https://www.url2png.com/)
IP Address Trace (http://www.ip-tracker.org/)
IP Determiner (DSLReports) (https://www.dslreports.com/whois)
IP Determiner (http://www.ipdatabase.com/)
IP Spam Check (http://www.spamhaus.org/lookup.lasso)
iPhone Emulator (http://iphone4simulator.com/)
JavaScript Compressor (http://dean.edwards.name/packer/)
JavaScript Linter (JSHint) (http://jshint.com/)
JavaScript Linter (JSLint) (http://www.jslint.com/)
JSON Formatter (http://bit.ly/2cX1dXT)
JSON Validator (http://pro.jsonlint.com/)
Layout Bug Test (script) (http://bit.ly/2czWyeT)
Link Analysis (http://juicystudio.com/services/linktest.php)
Link Check (LinkTiger) (http://www.linktiger.com/)
Link Check (Site Valet) (http://valet.webthing.com/link/)
Link Check (W3C) (http://validator.w3.org/checklink)
Load Time and Object Check (http://bit.ly/2cl1DDw)
Load Time Check (http://bit.ly/2cRR4N7)
Lynx Viewer (http://www.delorie.com/web/lynxview.html)
Malware and Security Scanner (http://sitecheck.sucuri.net/)
Markup Validator (http://www.validome.org/)
MD5 and SHA Hash Generator (http://onlinemd5.com/)
MD5 Encrypter (http://www.md5online.org/md5-encrypt.html)
Microformat Extractor and Transformer (http://microform.at/)
Mobile Emulator (http://mtld.mobi/emulator.php)
Mobile-Friendliness Check (http://bit.ly/1TaiOL0)
MX Lookup (http://mxtoolbox.com/)
Network Intrusion Prevention and Analysis (Kismet; command-line tool) (https://kismetwireless.net/)
Network Intrusion Prevention and Analysis (Snort; command-line tool) (https://www.snort.org/)
Open Graph and Semantics Extractor (https://developers.facebook.com/tools/debug)
Opera Mini Emulator (http://opr.as/2cKpahy)
Password Generator (Arantius.com) (http://tools.arantius.com/password)
Password Generator (GRC) (https://www.grc.com/passwords.htm)
Password Generator (Packetizer) (https://secure.packetizer.com/pwgen/)
Password Security Check https://howsecureismypassword.net/
Password Security Check (GRC) (https://www.grc.com/haystack.htm)
Performance and Scalability Test (Pylot; command-line tool) (http://www.pylot.org/)
Performance and Scalability Test (Tsung; command-line tool) (http://tsung.erlang-projects.org/)
PGP Decrypter (http://www.igolder.com/pgp/decryption/)
PGP Encrypter (http://www.igolder.com/pgp/encryption/)
PGP Key Generator (http://www.igolder.com/pgp/generate-key/)
Ping Tool (https://tools.pingdom.com/ping/)
Ping Tool (Regional) (http://bit.ly/2coze1f)
P3P Validator (http://www.w3.org/P3P/validator.html)
QA Style Sheet (bookmarklet) (https://github.com/j9t/qa-style-sheet)
RDF Validator (http://www.w3.org/RDF/Validator/)
Reputation and Safety Check (https://www.mywot.com/)
Responsiveness Test (http://www.viewlike.us/)
Reverse IP Lookup (http://mxtoolbox.com/ReverseLookup.aspx)
Rich Pin Validator (http://bit.ly/2cBCh7x)
robots.txt Syntax Check (http://bit.ly/2cl6HYm)
RSS and Atom Feed Validator (http://validator.w3.org/feed/)
SADiC Validator (http://bit.ly/2cUCpzP)
SBML Validator (http://sbml.org/Facilities/Validator/)
Schema Generator (http://schema-creator.org/)
Section 508 Check (http://www.508checker.com/)
Section 508 and WCAG 1.0 Check (Site Valet) (http://valet.webthing.com/access/url.html)
Section 508 and WCAG 2.0 Check (Cynthia Says) (http://www.cynthiasays.com/)
Section 508, WCAG 2.0, and BITV 1.0 Check (http://achecker.ca/checker/)
Security Breach Victim Check (https://haveibeenpwned.com/)
Security Analysis (OWASP Mantra; browser extension) (https://sourceforge.net/projects/getmantra/)
Semantics Check (Gecko browser extension) (https://mzl.la/2cjC31A)
Semantics Extractor (http://bit.ly/2cp0MTp)
Semantics Parser and Extractor (http://buzzword.org.uk/swignition/try)
SHA-512 Hash Generator (http://bit.ly/2cWHLKX)
Sitemap Validator (http://www.validome.org/google/validate)
SPDY Implementation Check (http://spdycheck.org/)
SQL Injection and Database Check (command-line tool) (http://sqlmap.org/)
SQL Injection Scanner (command-line tool) (http://bit.ly/2ctd5fN)
SQL Validator (http://developer.mimer.se/validator/index.htm)
SSL Certificate Check (DigiCert) (https://www.digicert.com/help/)
SSL Certificate Check (SSL Shopper) (https://www.sslshopper.com/ssl-checker.html)
SSL Client Check (https://www.howsmyssl.com/)
SSL Scanner (command-line tool) (https://github.com/iSECPartners/sslyze)
SSL Server Test (https://www.ssllabs.com/ssltest/)
Traceroute Tool (https://cloudmonitor.ca.com/en/traceroute.php)
Structured Data Test (Google) (https://search.google.com/structured-data/testing-tool)
Structured Data Test (Yandex) (https://webmaster.yandex.com/microtest.xml)
SVG Validator (http://bit.ly/2ctwMr0)
Traceroute Tool (Visualized) (http://traceroute.monitis.com/)
Trustworthiness Check (http://www.scamadviser.com/)
Twitter Card Test (https://cards-dev.twitter.com/validator)
Type Diff (https://tiff.herokuapp.com/)
Type Live Test (http://typewonder.com/)
Type Scale (http://type-scale.com/)
Type Scale (Modular) (http://www.modularscale.com/)
UI Test Automation (Ghost Inspector; browser extension) (https://ghostinspector.com/)
UI Test Automation (Screenster) (http://screenster.io/)
Universal Validator (http://watson.addy.com/)
User Agent Detector (http://ua.met.cz/)
User Identity Generator (http://bit.ly/2c84dAz)
Viewport Size Determiner (http://bit.ly/2cScuWp)
Virus Scanner (http://www.virustotal.com/)
Wake-on-LAN Service (http://www.dslreports.com/wakeup)
WCAG 1.0 Check (SIDAR) (http://www.sidar.org/hera/)
WCAG 1.0 Check (TAW) (http://www.tawdis.net/)
WCAG 2.0 Check (BOIA) (http://www.boia.org/)
WCAG 2.0 Check (Evaluera) (http://www.evaluera.co.uk/)
Web Application Security Analysis (Canoo; command-line tool) (http://bit.ly/2cT9wFm)
Web Application Security Analysis (OWASP; server application) (https://sourceforge.net/projects/owasp/)
Web Application Security Analysis (Skipfish; command-line tool) (https://github.com/spinkham/skipfish)
Web App Test Automation (command-line tool) (https://github.com/svenfuchs/steam)
Web Font Generator (http://bit.ly/2cWYrlz)
Website Analysis (Alexa) (http://www.alexa.com/)
Website Analysis (Nibbler) (http://nibbler.silktide.com/)
Website Analysis (RankFlex) (http://www.rankflex.com/en/)
Website Analysis (Site Analyzer) (https://www.site-analyzer.com/)
Website Analysis (StatsCrop) (http://www.statscrop.com/)
Website Analysis (UITest.com) (http://uitest.com/en/check/)
Website Blockade Check for China (http://www.blockedinchina.net/)
Website Blockade Check for England (https://www.blocked.org.uk/)
Website Browser and Location Speed Test (http://bit.ly/2cGeYrO)
Design Diff (script) (https://percy.io/)
Website Design History (DomainTools) (http://bit.ly/2cjC0mD)
Website Design History (Screenshots.com) (https://www.screenshots.com/)
Website Fingerprint Check (https://www.grc.com/fingerprints.htm)
Website Grader (Website Grader)
Website Monitoring Service (http://www.montastic.com/)
Website Performance Analysis (GTmetrix) (https://gtmetrix.com/)
Website Performance Analysis (IISpeed) (https://www.iispeed.com/pagespeed/insights)
Website Performance Analysis (Page Performance; WebKit browser extension) http://bit.ly/2cqOoRk)
Website Performance Analysis (PageSpeed) (http://bit.ly/2coEeD8)
Website Performance Analysis (Pingdom) (https://tools.pingdom.com/fpt/)
Website Performance Analysis (WebPagetest) (http://www.webpagetest.org/)
Website Performance Analysis (YSlow; browser extension) (http://yslow.org/)
Website Review (http://www.reviewmyweb.com/)
Website Technology Analysis (http://builtwith.com/)
Website Timer (http://www.octagate.com/service/SiteTimer/)
XHTML 1.0 Schema Validator (http://schneegans.de/sv/)
XML Schema Validator (http://bit.ly/2ctvqJZ)
XML Validator (http://www.xmlvalidation.com/)
XML Well-Formedness Check and Validator (http://bit.ly/2cTlfnh)
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