🗂 The perfect Front-End Checklist for modern websites and meticulous developers
It is based on Front-End developers' years of experience, with the additions coming from some other open-source checklists.
All items in the Front-End Checklist are required for the majority of the projects, but some elements can be omitted or are not essential (in the case of an administration web app, you may not need RSS feed for example). We choose to use 3 levels of flexibility:
Some resources possess an emoticon to help you understand which type of content / help you may find on the checklist:
You can contribute to the Front-End Checklist App reading the CONTRIBUTING.md file which explains everything about the project.
Notes: You can find a list of everything that could be found in theof an HTML document.
The next 2 meta tags (Charset and Viewport) need to come first in the head.
Page Title less than 55 characters
favicon.ico, put it at the root of your site. Normally you won't need to use any markup. However, it's still good practice to link to it using the example below. Today, PNG format is recommended over
.icoformat (dimensions: 32x32px).
Minimum required xml markup for the
browserconfig.xmlfile is as follows:
rel="canonical"to avoid duplicate content.
langattribute of your website is specified and related to the language of the current page.
[ ] RSS feed: If your project is a blog or has articles, an RSS link was provided.
[ ] CSS Critical: The CSS critical (or "above the fold") collects all the CSS used to render the visible portion of the page. It is embedded before your principal CSS call and betweenin a single line (minified).
- 🛠 Critical by Addy Osmani on GitHub automates this.
Visualize and generate automatically our social meta tags with Meta Tags
Facebook OG and Twitter Cards are, for any website, highly recommended. The other social media tags can be considered if you target a particular presence on those and want to ensure the display.
Notes: Usingog:image:widthandog:image:heightwill specify the image dimensions to the crawler so that it can render the image immediately without having to asynchronously download and process it.
[ ] Error pages: Error 404 page and 5xx exist. Remember that the 5xx error pages need to have their CSS integrated (no external call on the current server).
[ ] Noopener: In case you are using external links with
target="_blank", your link should have a
rel="noopener"attribute to prevent tab nabbing. If you need to support older versions of Firefox, use
Notes: Using web fonts may cause Flash Of Unstyled Text/Flash Of Invisible Text - consider having fallback fonts and/or utilizing web font loaders to control behavior. * 📖 Google Technical considerations about webfonts
[ ] Webfont size: Webfont sizes don't exceed 2 MB (all variants included).
[ ] Webfont loader: Control loading behavior with a webfont loader
Notes: Take a look at CSS guidelines and Sass Guidelines followed by most Front-End developers. If you have a doubt about CSS properties, you can visit CSS Reference. There is also a short Code Guide for consistency.
- [ ] embedded or inline CSS: Avoid at all cost embedding CSS in tags or using inline CSS: only use for valid reasons (e.g. background-image for slider, critical CSS).
- [ ] Vendor prefixes: CSS vendor prefixes are used and are generated accordingly with your browser support compatibility.
- [ ] Concatenation: CSS files are concatenated in a single file (Not for HTTP/2).
- [ ] Minification: All CSS files are minified.
- [ ] Non-blocking: CSS files need to be non-blocking to prevent the DOM from taking time to load.
- [ ] Unused CSS: Remove unused CSS.
- [ ] Stylelint: All CSS or SCSS files are without any errors.
[ ] Responsive web design: All pages were tested at the following breakpoints: 320px, 768px, 1024px (can be more / different according to your analytics). Responsive Checker -
[ ] CSS Validator: The CSS was tested and pertinent errors were corrected.
- [ ] Desktop Browsers: All pages were tested on all current desktop browsers (Safari, Firefox, Chrome, Internet Explorer, EDGE...).
- [ ] Mobile Browsers: All pages were tested on all current mobile browsers (Native browser, Chrome, Safari...).
[ ] OS: All pages were tested on all current OS (Windows, Android, iOS, Mac...).
[ ] Design fidelity: Depending on the project and the quality of the creatives, you may be asked to be close to the design. You can use some tools to compare creatives with your code implementation and ensure consistency.
- [ ] Reading direction: All pages need to be tested for LTR and RTL languages if they need to be supported.
Notes: For a complete understanding of image optimization, check the free ebook Essential Image Optimization from Addy Osmani.
- [ ] Optimization: All images are optimized to be rendered in the browser. WebP format could be used for critical pages (like Homepage).
- 🛠 Imagemin
- 🛠 Use ImageOptim to optimise your images for free.
- 🛠 Use KeyCDN Image Processing for image optimization in real time.
- 🛠 Use Kraken.io awesome alternative for both png and jpg optimization. Up to 1mb per files on free plan.
- 🛠 TinyPNG losslessly optimises png, apng (animated png) and jpg images. Free and paid version available.
- 🛠 ZorroSVG jpg-like compression for transparent images using svg masking.
- 🛠 SVGO a Nodejs-based tool for optimizing SVG vector graphics files.
- 🛠 SVGOMG a web-based GUI version of SVGO for optimising your svgs online.
- [ ] Picture/Srcset: You use picture/srcset to provide the most appropriate image for the current viewport of the user.
- [ ] Retina: You provide layout images 2x or 3x, support retina display.
- [ ] Sprite: Small images are in a sprite file (in the case of icons, they can be in an SVG sprite image).
- [ ] Width and Height: Setwidthandheightattributes onif the final rendered image size is known (can be omitted for CSS sizing).
- [ ] Alternative text: Allhave an alternative text which describes the image visually.
- [ ] Lazy loading: Images are lazyloaded (A noscript fallback is always provided). > * 🛠 Native lazy loading polyfill
- [ ] Modernizr: If you need to target some specific features you can use a custom Modernizr to add classes in your tag.
- [ ] ESLint: No errors are flagged by ESLint (based on your configuration or standards rules).
Scan and check your web site
- [ ] HTTPS: HTTPS is used on every page and for all external content (plugins, images...).
- [ ] HTTP Strict Transport Security (HSTS): The HTTP header is set to 'Strict-Transport-Security'.
- [ ] Cross Site Request Forgery (CSRF): You ensure that requests made to your server-side are legitimate and originate from your website / app to prevent CSRF attacks.
- [ ] Cross Site Scripting (XSS): Your page or website is free from XSS possible issues.
- [ ] Content Type Options: Prevents Google Chrome and Internet Explorer from trying to mime-sniff the content-type of a response away from the one being declared by the server.
- [ ] X-Frame-Options (XFO): Protects your visitors against clickjacking attacks.
- [ ] Content Security Policy: Defines how content is loaded on your site and from where it is permitted to be loaded. Can also be used to protect against clickjacking attacks.
- [ ] Goals to achieve: Your pages should reach these goals:
- First Meaningful Paint under 1 second
- Time To Interactive under 5 seconds for the "average" configuration (a $200 Android on a slow 3G network with 400ms RTT and 400kbps transfer speed) and under 2 seconds for repeat visits
- Critical file size under 170Kb gzipped
[ ] Minified HTML: Your HTML is minified.
[ ] Lazy loading: Images, scripts and CSS need to be lazy loaded to improve the response time of the current page (See details in their respective sections).
[ ] Cookie size: If you are using cookies be sure each cookie doesn't exceed 4096 bytes and your domain name doesn't have more than 20 cookies.
- [ ] Third party components: Third party iframes or components relying on external JS (like sharing buttons) are replaced by static components when possible, thus limiting calls to external APIs and keeping your user's activity private.
Preparing upcoming requests
- [ ] DNS resolution: DNS of third-party services that may be needed are resolved in advance during idle time usingdns-prefetch.
- [ ] Preconnection: DNS lookup, TCP handshake and TLS negotiation with services that will be needed soon is done in advance during idle time usingpreconnect.
- [ ] Prefetching: Resources that will be needed soon (e.g. lazy loaded images) are requested in advance during idle time usingprefetch.
- [ ] Preloading: Resources needed in the current page (e.g. scripts placed at the end of ) in advance usingpreload.
- [ ] Google PageSpeed: All your pages were tested (not only the homepage) and have a score of at least 90/100.
Notes: You can watch the playlist A11ycasts with Rob Dodson 📹
- [ ] Color contrast: Color contrast should at least pass WCAG AA (AAA for mobile).
- [ ] H1: All pages have an H1 which is not the title of the website.
- [ ] Headings: Headings should be used properly and in the right order (H1 to H6).
- [ ] Specific HTML5 input types are used: This is especially important for mobile devices that show customized keypads and widgets for different types.
- [ ] Label: A label is associated with each input form element. In case a label can't be displayed, usearia-labelinstead.
- [ ] Accessibility standards testing: Use the WAVE tool to test if your page respects the accessibility standards.
- [ ] Keyboard navigation: Test your website using only your keyboard in a previsible order. All interactive elements are reachable and usable.
- [ ] Screen-reader: All pages were tested in a screen-reader (VoiceOver, ChromeVox, NVDA or Lynx).
- [ ] Focus style: If the focus is disabled, it is replaced by visible state in CSS.
- [ ] Google Analytics: Google Analytics is installed and correctly configured.
- [ ] Search Console: Search Console is installed and correctly configured. It is a free service offered by Google that helps you monitor, maintain, and troubleshoot your site's presence in Google Search results.
- [ ] Headings logic: Heading text helps to understand the content in the current page.
- [ ] sitemap.xml: A sitemap.xml exists and was submitted to Google Search Console (previously Google Webmaster Tools).
- [ ] robots.txt: The robots.txt is not blocking webpages.
- [ ] Structured Data: Pages using structured data are tested and are without errors. Structured data helps crawlers understand the content in the current page.
- 📖 Introduction to Structured Data - Search - Google Developers
- 📖 JSON-LD
- 📖 Microdata
- 🛠 Test your page with the Rich Restults Test
- 🛠 Complete list of vocabularies that can be used as structured data. Schema.org Full Hierarchy
- [ ] Sitemap HTML: An HTML sitemap is provided and is accessible via a link in the footer of your website.
- [ ] Pagination link tags: Providerel="prev"andrel="next"to indicate paginated content.
The Front-End Checklist is also available in other languages. Thanks for all translators and their awesome work!
- 🇯🇵 Japanese: miya0001/Front-End-Checklist
- 🇪🇸 Spanish: eoasakura/Front-End-Checklist-ES
- 🇨🇳 Chinese: JohnsenZhou/Front-End-Checklist
- 🇰🇷 Korean: kesuskim/Front-End-Checklist
- 🇧🇷 Portuguese: jcezarms/Front-End-Checklist
- 🇻🇳 Vietnamese: euclid1990/Front-End-Checklist
- 🇹🇼 Traditional Chinese: EngineLin/Front-End-Checklist
- 🇫🇷 French: ynizon/Front-End-Checklist
- 🇷🇺 Russian: ungear/Front-End-Checklist
- 🇹🇷 Turkish: eraycetinay/Front-End-Checklist
- 🇩🇪 German: xfuture603/Front-End-Checklist
- 🇵🇱 Polish: mbiesiad/Front-End-Checklist
Front-End Checklist Badge
If you want to show you are following the rules of the Front-End Checklist, put this badge on your README file![![Front‑End_Checklist followed](https://img.shields.io/badge/Front‑End_Checklist-followed-brightgreen.svg)](https://github.com/thedaviddias/Front-End-Checklist/)
Open an issue or a pull request to suggest changes or additions.
The Front-End Checklist repository consists of two branches:
This branch consists of theREADME.mdfile that is automatically reflected on the Front-End Checklist website.
This branch will be used to make some significant changes to the structure, content if needed. It is preferable to use the master branch to fix small errors or add a new item.
If you have any question or suggestion, don't hesitate to use Gitter or Twitter:
This project exists thanks to all the people who contribute. [Contribute].
Thank you to all our backers! 🙏 [Become a backer]
Support this project by becoming a sponsor. Your logo will show up here with a link to your website. [Become a sponsor]