Instantly create and customize your .prettierrc configuration file with our free online tool. Generate valid JSON for code consistency in your web projects.
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Free .prettierrc JSON Configuration Builder
This utility provides a professional-grade, browser-based interface for developers to generate accurate, valid .prettierrc JSON configuration files. Designed for modern web development workflows, this tool removes the friction of manual JSON syntax management.
Core Features
- Interactive Rule Selector: Toggle popular Prettier rules (e.g.,
semi,singleQuote,tabWidth,trailingComma,printWidth,endOfLine) using intuitive UI components. - Real-Time JSON Preview: A syntax-highlighted output window updates instantly as you adjust settings, showing exactly how the final JSON file will look.
- Direct Download: Export your generated configuration as a valid
.prettierrcfile instantly. - One-Click Copy: Copy the configuration to your clipboard with a single click, featuring a user-friendly "Copied!" toast notification.
- In-App Documentation: Each setting includes a toggleable info icon that displays a brief, expert explanation of what the rule does and why you might want to enable it.
UI Layout
- Header: A clean, minimalist header displaying the tool name and a brief instructional subtitle.
- Main Tool Area: A two-column responsive layout:
- Left Column (Configuration): A scrollable list of form controls categorized by "Indentation," "Formatting," and "Syntax." Each input is clearly labeled with default values visible.
- Right Column (Output): A fixed-height container displaying the generated JSON code with a monospaced font, clearly delineated from the controls.
- Action Bar: A sticky footer bar containing "Reset to Defaults," "Download .prettierrc," and "Copy to Clipboard" buttons.
Design & Aesthetics
- Color Palette: Strictly light-mode.
- Backgrounds:
#ffffff(White) and#f8fafc(Slate-50). - Primary Buttons:
#4f46e5(Indigo-600) with a subtle hover state. - Text:
#1f2937(Slate-800) for high readability. - Borders/Dividers:
#e2e8f0(Slate-200).
- Backgrounds:
- Typography: Clean, sans-serif system fonts (Inter, system-ui) for professional readability. Monospaced font for JSON output (Fira Code or Courier).
- Transitions: Smooth easing transitions (
transition-all duration-200) for button interactions and input focus states.
Technical Requirements
- Framework: Pure Vanilla JavaScript, HTML5, and CSS3.
- Storage: Absolutely no
localStorage,sessionStorage, or cookies. Configuration state must be stored in volatile JavaScript variables. - Modals: All UI interactions requiring confirmation (e.g., reset) must use custom HTML/CSS modal components rather than browser-native
confirm()oralert()functions. - Sandbox Safety: Must be compatible with strictly sandboxed environments. No cross-origin requests; all functionality must be self-contained within the single HTML file.
- Responsiveness: The two-column layout must collapse into a single-column stacked layout on viewports smaller than 768px.
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Frequently Asked Questions
Everything you need to know about using this application.
What is a .prettierrc file and why do I need one?
A .prettierrc file is a configuration file used by the Prettier code formatting tool to standardize code style across a project. By placing this file in the root of your repository, you ensure that every developer contributes code with the same indentation, quoting, and spacing rules. Using a shared configuration file eliminates "style wars" in pull requests and maintains high readability in collaborative environments. This builder helps you define these rules without needing to memorize the specific JSON syntax requirements.
How do I use the generated JSON configuration?
Once you have selected your preferred settings using the builder, simply copy the generated JSON text. Create a new file named .prettierrc (with a leading dot) in the root directory of your project and paste the content into it. Alternatively, you can use the download button provided by this tool to save the file directly to your machine. After saving, ensure you have the Prettier extension installed in your code editor to automatically apply these rules when you save your files.
Does this tool format my actual code?
No, this tool acts strictly as a generator for the .prettierrc configuration file that tells Prettier how to behave. It does not access your local files or execute code formatting logic itself. To format your actual code, you must use the Prettier CLI, a pre-commit hook (like Husky), or an editor-integrated plugin (such as the VS Code Prettier extension). This app specifically helps you build the ruleset that those tools will follow.
Is this tool safe for sensitive projects?
Yes, this tool is 100% client-side. The JSON configuration generation happens entirely within your web browser memory. No data is sent to a server, saved in databases, or stored via local storage technologies. Because we do not use cookies or persistent storage, every time you refresh the page, the settings will reset. This architecture ensures maximum privacy and security for your development workflow, as your configuration data never leaves your local machine.
