CodeRef Start
New productYour start page, in every new tab
CodeRef Start puts the sites, feeds, notes and to-dos you use every day on one page, and opens it in every new tab. Use it on your own or share pages with your team. Free for 3 pages, PRO $24 a year, Team $29 a month.
- Chrome new tab
- Save all tabs
- Import bookmarks
- Team pages
- Template gallery
CodeRef Start extension for Chrome, Edge & Brave
Free. Opens your start page in every new tab, works offline, and saves pages or all open tabs in one click.
Every new tab, instantly
The Chrome extension opens your page in every new tab, even offline, with search and a command menu.
25 widgets
Bookmarks, speed dial, RSS, weather, notes, to-dos, Kanban, calendars, GitHub and your CodeRef cheat sheets.
Save in one click
Save a page, every open tab or a right-clicked link. Import your browser or start.me bookmarks.
Built for teams
Shared, branded team pages with roles, announcements and link analytics, rolled out by policy.
Design Systems of Top Brands
Drop a brand's DESIGN.md into your project and your AI coding assistant builds UI in that style — the right colors, type, spacing and components, on the first try.
Works with
- Claude Code
- Cursor
- Codex
- Gemini
- ChatGPT
- and other AI coding assistants
- 1,127 design systems
- Apple, Stripe, Airbnb, Notion and every top brand, plus indie and mobile apps.
- Tokens your agent can follow
- Colors, typography, spacing and components, written as rules — not screenshots.
- Real site screenshots
- See each brand's live site next to its DESIGN.md before you pick one.
- Free, no sign-up
- Copy, download or curl a DESIGN.md straight into your project root.
- AppleButton
Apple DESIGN.mdView →Apple
WebA photography-first interface that turns marketing into a museum gallery. Edge-to-edge product tiles alternate light and dark canvases, framed by SF Pro Display headlines with negative letter-spacing and a single Action Blue (#0066cc)…
○ Light· SF Pro Text
- GoogleButton
Google DESIGN.mdView →Google
BrandsGoogle began as a search engine and now describes a product family used by billions; its stated mission is to organize the world's information and make it universally accessible and useful.
○ Light
- MicrosoftButton
Microsoft DESIGN.mdView →Microsoft
BrandsMicrosoft makes public experiences for people, teams, and organizations across consumer software, cloud services, devices, and developer tools.
○ Light
- NetflixButton
Netflix DESIGN.mdView →Netflix
BrandsNetflix is the streaming interface that taught the world what "lean-back" entertainment software should feel like — a dark, cinematic theater where the content is the only thing that glows.
◐ Dark· Netflix Sans
- SpotifyButton
Spotify DESIGN.mdView →Spotify
WebSpotify's web interface is a dark, immersive music player that wraps listeners in a near-black cocoon (#121212, #181818, #1f1f1f) where album art and content become the primary source of color.
◐ Dark· SpotifyMixUI
- AirbnbButton
Airbnb DESIGN.mdView →Airbnb
WebA warm, generous consumer marketplace anchored on a clean white canvas and Airbnb Rausch (#ff385c), the single brand voltage that carries every primary CTA, search-button orb, and rating dot.
○ Light· Airbnb Cereal VF
- UberButton
Uber DESIGN.mdView →Uber
WebAn inspired interpretation of Uber's design language — a transportation-and-delivery super-app brand whose web surface is a black-and-white duet, framed by a custom geometric display sans, accented by a single signature pill shape (radius…
○ Light· UberMoveText
- StripeButton
Stripe DESIGN.mdView →Stripe
WebAn inspired interpretation of Stripe's design language — a financial-infrastructure brand built on a deep navy ink, an electric indigo primary, and a recurring atmospheric gradient mesh that occupies the upper third of nearly every…
○ Light· SF Pro Display
- TeslaButtonTesla DESIGN.mdView →
Tesla
WebTesla's website is an exercise in radical subtraction — a digital showroom where the product is everything and the interface is almost nothing.
○ Light· Universal Sans Display
- NikeButton
Nike DESIGN.mdView →Nike
Web|
○ Light· Helvetica Now Text Medium
- MetaButton
Meta DESIGN.mdView →Meta
WebMeta's design system spans hardware commerce (Quest VR, Ray-Ban Meta AI glasses) and brand surfaces with a confident product-merchandising voice.
○ Light· Optimistic VF
- OpenAIButtonOpenAI DESIGN.mdView →
OpenAI
BrandsOpenAI's interface is the visual argument that powerful technology should feel quiet. The canvas is uncompromising near-black-on-white (#0d0d0d text on #ffffff), with the signature teal-green (#10a37f) reserved almost exclusively for the…
○ Light· OpenAI Sans
- AnthropicButton
Anthropic DESIGN.mdView →Anthropic
WebAn inspired interpretation of Anthropic's design language — a warm, paper-toned research brand built on ivory and oat surfaces, near-black ink, a custom serif for statements and a custom sans for everything else, with fully rounded pill…
○ Light· anthropicSans
- ClaudeButton
Claude DESIGN.mdView →Claude
WebA warm-canvas editorial interface for Anthropic's Claude product. The system anchors on a tinted cream canvas with serif display headlines, warm coral CTAs, and dark navy product surfaces (code editor mockups, model showcase cards).
○ Light· StyreneB
- NotionButton
Notion DESIGN.mdView →Notion
WebNotion presents itself as the all-in-one workspace through a confident, illustration-rich brand voice — anchored by a deep navy hero band ({colors.brand-navy}) decorated with brand-colored sticky-note dots and mesh wire illustrations, a…
○ Light· Notion Sans
- FigmaButton
Figma DESIGN.mdView →Figma
WebA confident black-and-white editorial frame interrupted by oversized, hand-cut pastel color blocks. The marketing canvas is rigorously monochrome — figmaSans variable type, pure white surfaces, pure black ink, pill-shaped CTAs — while each…
○ Light· figmaSans
- LinearButton
Linear DESIGN.mdView →Linear
WebA near-black product-focused marketing canvas built around #010102 (the deepest dark surface of any tool in this collection), light gray text (#f7f8f8), and the signature Linear lavender-blue (#5e6ad2) used as the single chromatic accent.
◐ Dark· Linear Display
- VercelButton
Vercel DESIGN.mdView →Vercel
WebAn inspired interpretation of Vercel's design language — a developer-platform brand whose surface is a stark black-and-ink duet on near-white canvas, broken at hero scale by a multi-color mesh gradient (cyan / blue / magenta / amber) that…
○ Light· Geist
- GitHubButton
GitHub DESIGN.mdView →GitHub
BrandsGitHub is the home of the world's software, and its interface reflects a deliberate engineering aesthetic: precise, legible, and quietly confident.
○ Light· SFMono-Regular
- SlackButton
Slack DESIGN.mdView →Slack
WebAn inspired interpretation of Slack's design language — a workplace messaging brand built on a deep aubergine primary, with cream-lavender hero gradients, blue inline links, and pill CTAs.
○ Light· Salesforce-Sans
Featured Interactive Developer Tools
Interactive utilities, real-time generators and compilers that run in your browser.
- ✨ NEW STUDIOActive Harmony: Triadic18.2:1 AAATextBgPrimarySecondaryAccentPress Space to randomize50-950 Shades
Realtime Colors Studio
Live Palette Generator & UI Previewer
Press Space to generate harmonized palettes. Preview in real time on authentic Landing Page, SaaS Dashboard, Blog, and UI Kit templates with WCAG contrast audits and 1-click Tailwind export.
Launch Realtime Colors →
- ⚡ ESSENTIAL TOOL✓ Valid JSONTypeScript Ready{"service": "coderef","tools": ["formatter", "colors"],"autoRepair": true}
JSON Formatter & Converter
Format, Validate, Repair & Convert
Fix malformed JSON with automatic bracket/trailing-comma repair. Convert JSON to TypeScript interfaces, YAML, XML, or CSV. Compare side-by-side diffs and run JMESPath queries.
Open JSON Formatter →
- 🚀 WEB SANDBOXHTMLCSSJS● Live Output<button class="btn-primary">Click Me</button>0 errors
HTML, CSS & JS Playground
All-in-One Live Web Sandbox
Write HTML, style with CSS, and run JavaScript side-by-side with instant live browser rendering. Includes Emmet abbreviation expansion, console output logs, and shareable links.
Open Playground →
- 📝 WRITING & DOCS# EditorPreview# Title- [x] Tested| Col 1 | Col 2 |Title☑ TestedTable Rendered
Markdown Editor & Cheat Sheet
Synchronized Live Preview & Tables
Full-featured Markdown authoring tool with synchronized scrolling, interactive visual Table Builder, HTML to Markdown converter, GFM task lists, and export to styled HTML or PDF.
Open Markdown Editor →
- 🔍 PATTERN ENGINEPattern: /([a-z]+)@([a-z.]+)/gi2 Matcheshello@coderef.xyzGroup 1: "hello" · Group 2: "coderef.xyz"
Regex Tester & Explainer
Pattern Highlighter & Code Generator
Interactive JavaScript regular expression tester with live match highlights, capture group color coding, plain-English pattern explanations, and multi-language code generation.
Open Regex Tester →
- 🌐 HTTP STUDIOGEThttps://api.github.com/zenStatus: 200 OK42 msHeaders (12) · JSON Response Parsed
REST API Client
Send HTTP Requests Like Postman
Compose GET, POST, PUT, DELETE requests directly in your browser. Configure headers, auth tokens, and body payloads, and inspect formatted JSON responses.
Open API Client →
- ✨ NEW EFFECTSAurora
Animated Backgrounds
Copy-Paste Hero Effects
Original animated backgrounds for your hero, footer or any section. Pick colors and speed, preview live, then copy plain HTML + JS or a prompt for your AI agent.
Browse Backgrounds →
- 🌿 GAME$ git checkout -b feature$ git commit$ git rebase main
Git Branching
Learn Git by Playing
Animated levels for branching, merging, rebasing and remotes. Type real git commands and watch the commit graph change.
Start Playing →
6:00 AM
Morning. Standup in ten minutes. Find the command you always forget.
Open Quick Reference →Noon. Wiring up an API. Send the request, then make sense of the response.
Open REST API Client →Afternoon. That one validation rule. Build the regex and watch every match light up.
Open Regex Tester →Evening. Time to merge. Practise the rebase before you run it for real.
Open Git Playground →Night. Side-project hours. Pick a dark design system and let your agent build it.
Open Dark DESIGN.md files →Developer cheat sheets
Cheat sheets (38)
ActionScript 3
LanguagesActionScript 3.0 classes for the Flash/AIR platform, grouped by package.
82 entries
Blogger
ApplicationsBlogger API v3 resources and methods, plus help for themes, layouts and gadgets.
42 entries
Browser Support
WebCan you use it? Support tables, Baseline status and usage examples for web platform features.
1214 entries
Characters
WebSpecial characters with their HTML entities: arrows, math, currency, punctuation, Greek and symbols.
179 entries
CMake
ToolsCMake commands for targets, control flow, finding packages, variables, modules and the CLI.
88 entries
CodeRef Start Extension
ToolsFree Chrome, Edge and Brave new tab extension: your start page, AI search and one-click tab saving.
Interactive tool
CSS
WebSelectors, layout, box model, typography and modern CSS features.
81 entries
CSS Grid
WebVisual cheat sheet for CSS Grid Layout — every property with live previews you can copy.
74 entries
Docker
ToolsDocker CLI for containers, images, volumes, networks and Compose, plus Dockerfile instructions.
90 entries
Drush
ToolsDrush commands for Drupal: cache, config, modules, database, users, roles and logs.
70 entries
Express
FrameworksExpress 5 API: application, request, response, router and middleware.
98 entries
Flexbox
WebVisual cheat sheet for CSS Flexible Box Layout — every property with live previews you can copy. The dashed box is the flex container.
61 entries
Git
ToolsEveryday Git commands for setup, staging, branching and remotes.
37 entries
Git Branching
ToolsLearn Git visually: run commands and watch an animated commit graph, with guided levels.
Interactive tool
HTML
WebElements, global attributes and input types of modern HTML.
181 entries
HTML & CSS Abbreviations
ToolsType ul>li*3 or d:f and get full HTML/CSS — live playground plus every built-in abbreviation.
491 entries
HTML DOM
WebDocument, Element, Node, Event and Window APIs for scripting web pages.
221 entries
Java
LanguagesJava SE 25 core classes by package, language features and JDK tools.
148 entries
JavaScript
LanguagesCore language built-ins: Array, String, Object, Promise, Math and more.
214 entries
jQuery
FrameworksSelectors, DOM manipulation, traversal, events, effects and Ajax.
197 entries
JSON Formatter
ToolsFormat, validate, repair, minify, convert (YAML/XML/CSV/TypeScript), compare and query JSON.
Interactive tool
Linux
SystemsEssential Linux commands for files, text, processes, users, networking and packages.
169 entries
Markdown
ToolsMarkdown editor with live preview and export, plus a cheat sheet of basic and extended syntax.
Interactive tool
mod_rewrite
SystemsApache mod_rewrite directives, RewriteRule flags, server variables and condition tests.
95 entries
MongoDB Shell
Databasesmongosh methods for collections, cursors and databases, plus query, update and aggregation operators.
117 entries
MySQL
DatabasesMySQL 8.4 statements, functions, data types and command-line tools.
156 entries
Node.js
FrameworksCore Node.js modules: fs, path, http, events, process, streams, crypto and more.
167 entries
Org Mode
ApplicationsOrg mode markup, TODOs, scheduling, tables, source blocks, export and key bindings for Emacs.
55 entries
PHP
LanguagesPHP functions for strings, arrays, files, JSON and dates, plus core language features.
257 entries
Python
LanguagesBuilt-in functions, core types and common standard library modules.
151 entries
Quick Reference
ToolsCopy-paste snippets by task for 24 languages and tools, including VS Code shortcuts — searchable across all.
1055 entries
R
LanguagesBase R for help, I/O, data structures, apply functions, strings, statistics and plotting.
119 entries
Realtime Colors Studio
ToolsLive color palette generator, WCAG contrast checker, and instant UI previewer on authentic templates.
Interactive tool
Regex Tester
ToolsTest JavaScript regular expressions with live highlighting, explanations and code generation.
Interactive tool
RegExp
ToolsRegular expression syntax: classes, anchors, quantifiers, groups, lookarounds and flags.
85 entries
Ruby
LanguagesRuby 3.4 core classes — String, Array, Hash, Enumerable, Kernel — and syntax guides.
266 entries
SVN
ToolsSubversion client, admin and inspection commands, properties and revision keywords.
77 entries
Underscore.js
FrameworksUnderscore.js helpers for collections, arrays, functions, objects and utilities.
118 entries
A–Z directory (308)
Bold topics have a full cheat sheet; the rest link to official docs and cheat sheets.