The Front-End Checklist is an exhaustive list of all elements you need to have / to test before launching your site / HTML page to production.
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:
means that the item is recommended but can be omitted in some particular situations.
means that the item is highly recommended and can eventually be omitted in some really particular cases. Some elements, if omitted, can have bad repercussions in terms of performance or SEO.
means that the item can't be omitted by any reason. You may cause a dysfunction in your page or have accessibility or SEO issues. The testing priority needs to be on these elements first.
Some resources possess an emoticon to help you understand which type of content / help you may find on the checklist:
- 📖: documentation or article
- 🛠: online tool / testing tool
- 📹: media or video content
You can contribute to the Front-End Checklist App reading the README_APP file which explain everything about the project.
Notes: You can find a list of everything that could be found in the
<head>of an HTML document.
- Doctype:
<!doctype html> <!-- HTML5 -->The next 3 meta tags (Charset, X-UA Compatible and Viewport) need to come first in the head.
- Charset:
<!-- Set character encoding for the document -->
<meta charset="utf-8">- X-UA-Compatible:
<!-- Instruct Internet Explorer to use its latest rendering engine -->
<meta http-equiv="x-ua-compatible" content="ie=edge">- Viewport:
<!-- Viewport for responsive web design -->
<meta name="viewport" content="width=device-width, initial-scale=1, viewport-fit=cover">- Title:
<!-- Document Title -->
<title>Page Title less than 55 characters</title>- Description:
<!-- Meta Description -->
<meta name="description" content="Description of the page less than 150 characters">- Favicons:
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).
<!-- Standard favicon -->
<link rel="icon" type="image/x-icon" href="https://example.com/favicon.ico">
<!-- Recommended favicon format -->
<link rel="icon" type="image/png" href="https://example.com/favicon.png">- Apple Web App Meta:
<!-- Apple Touch Icon (at least 200x200px) -->
<link rel="apple-touch-icon" href="/custom-icon.png">
<!-- To run web application in full-screen -->
<meta name="apple-mobile-web-app-capable" content="yes">
<!-- Status Bar Style (see Supported Meta Tags below for available values) -->
<!-- Has no effect unless you have the previous meta tag -->
<meta name="apple-mobile-web-app-status-bar-style" content="black">- Windows Tiles:
<!-- Microsoft Tiles -->
<meta name="msapplication-config" content="browserconfig.xml" />Minimum required xml markup for the browserconfig.xml file is as follows:
<?xml version="1.0" encoding="utf-8"?>
<browserconfig>
<msapplication>
<tile>
<square70x70logo src="small.png"/>
<square150x150logo src="medium.png"/>
<wide310x150logo src="wide.png"/>
<square310x310logo src="large.png"/>
</tile>
</msapplication>
</browserconfig>- Canonical:
rel="canonical"to avoid duplicate content.
<!-- Helps prevent duplicate content issues -->
<link rel="canonical" href="http://example.com/2017/09/a-new-article-to-read.html">- Language attribute:
langattribute of your website is specified and related to the language of the current page.
<html lang="en">- Direction attribute:
<html dir="rtl">- Alternate language:
<link rel="alternate" href="https://es.example.com/" hreflang="es">- Conditional comments:
-
RSS feed:
-
CSS Critical:
<style></style>in a single line (minified).
- 🛠 Critical by Addy Osmani on GitHub automates this.
- CSS order:
<head>. (Except the case where sometimes JS files are loaded asynchronously on top of your page).
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.
- Facebook Open Graph:
Notes: Using
og: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.
<meta property="og:type" content="website">
<meta property="og:url" content="https://example.com/page.html">
<meta property="og:title" content="Content Title">
<meta property="og:image" content="https://example.com/image.jpg">
<meta property="og:description" content="Description Here">
<meta property="og:site_name" content="Site Name">
<meta property="og:locale" content="en_US">
<!-- Next tags are optional but recommended -->
<meta property="og:image:width" content="1200">
<meta property="og:image:height" content="630">
- 📖 A Guide to Sharing for Webmasters
- 📖 Best Practices - Sharing
- 🛠 Test your page with the Facebook OG testing
- Twitter Card:
<meta name="twitter:card" content="summary">
<meta name="twitter:site" content="@site_account">
<meta name="twitter:creator" content="@individual_account">
<meta name="twitter:url" content="https://example.com/page.html">
<meta name="twitter:title" content="Content Title">
<meta name="twitter:description" content="Content description less than 200 characters">
<meta name="twitter:image" content="https://example.com/image.jpg">
- 📖 Getting started with cards — Twitter Developers
- 🛠 Test your page with the Twitter card validator
- HTML5 Semantic Elements:
-
Error pages:
-
Noopener:
target="_blank", your link should have arel="noopener"attribute to prevent tab nabbing. If you need to support older versions of Firefox, userel="noopener noreferrer".
- Clean up comments:
- W3C compliant:
- HTML Lint:
- Link checker:
- Adblockers test:
- Webfont format:
-
Webfont size:
-
Webfont loader:
- Responsive Web Design:
- CSS Print:
- Preprocessors:
- Unique ID:
- Reset CSS:
- 📖 Reset.css
- 📖 Normalize.css
- 📖 Reboot
- JS prefix:
- embedded or inline CSS:
<style>tags or using inline CSS: only use for valid reasons (e.g. background-image for slider, critical CSS). - Vendor prefixes:
- Concatenation:
- Minification:
- Non-blocking:
- Unused CSS:
Remove unused CSS.
- Stylelint:
-
Responsive web design:
-
CSS Validator:
- Desktop Browsers:
- Mobile Browsers:
- OS:
- Design fidelity:
- Reading direction:
- Optimization:
- 🛠 Imagemin
- 🛠 Use ImageOptim to optimise your images for free.
- 🛠 Use Kraken.io awesome alternative for both png and jpg optimization. Up to 1mb per files on free plan.
- 🛠 TinyPNG losslessly optimise 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:
- Retina:
- Sprite:
- Width and Height:
widthandheightattributes on<img>if the final rendered image size is known (can be omitted for CSS sizing). - Alternative text:
<img>have an alternative text which describe the image visually. - Lazy loading:
- JavaScript Inline:
- Concatenation:
- Minification:
.minsuffix). - JavaScript security:
-
noscripttag:<noscript>tag in the HTML body if a script type on the page is unsupported or if scripting is currently turned off in the browser. This will be helpful in client-side rendering heavy apps such as React.js, see examples. - Non-blocking:
asyncor deferred usingdeferattribute. - Optimized and updated JS libraries:
- Modernizr:
<html>tag. - ESLint:
- HTTPS:
- HTTP Strict Transport Security (HSTS):
- Cross Site Request Forgery (CSRF):
- Cross Site Scripting (XSS):
- Content Type Options:
- X-Frame-Options (XFO):
- Content Security Policy:
- Page weight:
-
Minified HTML:
-
Lazy loading:
-
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:
- DNS resolution:
dns-prefetch. - Preconnection:
preconnect. - Prefetching:
prefetch. - Preloading:
<body>) in advance usingpreload. - Google PageSpeed:
- Progressive enhancement:
- Color contrast:
- H1:
- Headings:
- Role banner:
<header>hasrole="banner". - Role navigation:
<nav>hasrole="navigation". - Role main:
<main>hasrole="main". - Specific HTML5 input types are used:
- Label:
aria-labelinstead. - Accessibility standards testing:
- Keyboard navigation:
- Screen-reader:
- Focus style:
- Google Analytics:
- Headings logic:
- sitemap.xml:
- robots.txt:
- 📖 The robots.txt file
- 🛠 Test your robots.txt with Google Robots Testing Tool
- Structured Data:
- 📖 Introduction to Structured Data - Search - Google Developers
- 📖 RDFa - Linked Data in HTML
- 📖 JSON-LD
- 📖 Microdata
- 🛠 Test your page with the Structured Data Testing Tool
- 🛠 Complete list of vocabularies that can be used as structured data. Schema.org Full Hierarchy
- Sitemap HTML:
- Pagination link tags:
rel="prev"andrel="next"to indicate paginated content. - 🇯🇵 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
Notes: Using webfonts may cause Flash Of Unstyled Text/Flash Of Invisible Text - consider having fallback fonts and/or utilizing webfont loaders to control behavior.
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.
<div id="js-slider" class="my-slider">
<!-- Or -->
<div id="id-used-by-cms" class="js-slider my-slider">Notes: For a complete understanding of image optimization, check the free ebook Essential Image Optimization from Addy Osmani.
<noscript>
You need to enable JavaScript to run this app.
</noscript><link rel="dns-prefetch" href="https://example.com"><link rel="preconnect" href="https://example.com"><link rel="prefetch" href="image.png"><link rel="preload" href="app.js">Notes: You can watch the playlist A11ycasts with Rob Dodson 📹
<!-- Example: Pagination link tags for page 2 of a paginated list -->
<link rel="prev" href="https://example.com/?page=1">
<link rel="next" href="https://example.com/?page=3">The Front-End Checklist is also available in other languages. Thanks for all translators and their awesome work!
If you want to show you are following the rules of the Front-End Checklist, put this badge on your README file!
➔
[](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 the README.md file 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]
