Web app development

Create responsive web designs efficiently with Claude

May 16, 2025

・ by

Claude and the Anthropic Team

Table of contents

Responsive web design is no longer optional, it’s foundational. Modern users expect seamless experiences across devices, whether they’re browsing on a phone, tablet, or desktop. For developers and designers, that means ensuring layouts adapt dynamically, content scales fluidly, and interactivity remains smooth no matter the screen size.

Claude accelerates this process in two ways:

Claude.ai: Anthropic’s AI coding tool, available in your browser or via API, that generates well-structured HTML/CSS/JS boilerplate code, recommends design patterns, and explains best practices, all in natural language.
Claude Code: Anthropic’s terminal-based, agentic coding tool that integrates directly with your development environment to understand, modify, and improve your front-end frameworks.

In this guide, we’ll show how each version of Claude streamlines the process of creating responsive, framework-based web designs. From a single-page site to complex production layouts, Claude helps you go from idea to implementation faster and cleaner.

Rapid prototyping

Claude.ai can scaffold an entire responsive page from a single prompt. A classic example lives in the Prompt Library under Website wizard. Paste the system + user prompt verbatim, and Claude returns a one-page site that already includes:

A <meta name="viewport"...> tag
Mobile-first CSS with flexbox or grid and media queries (%, vh, vw, rem)
Semantic HTML5 (<header>, <nav>, <main>, <footer>)
JavaScript interactivity—e.g., rotating taglines, collapsible menus, modal dialogs
Inline comments so a developer can extend or swap placeholders later

<head>
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <style>
    .container {
      display: flex;
      flex-direction: column;
      padding: 20px;
    }
    @media (min-width: 768px) {
      .container {
        flex-direction: row;
      }
    }
  </style>
</head>

This auto-generated layout saves hours of scaffolding time while providing a well-commented, extensible foundation to build from.

Refine and scale with Claude Code

For more complex and production-ready workflows, Claude Code is the tool of choice. This agentic, terminal-based tool integrates directly with your local repo and development stack, helping you build and refactor responsive designs at scale—without ever leaving your coding environment.

Once installed via:

npm install -g @anthropic-ai/claude-code

You can prompt Claude Code like so:

find all layout styles using fixed pixel widths and convert to responsive units

Or:

refactor this CSS grid layout to support two columns on desktop, one column on mobile

Claude Code will inspect the relevant files, suggest diffs, and only apply changes after user confirmation. It also supports memory (via CLAUDE.md) so it can remember your preferred breakpoints, color themes, and naming conventions across sessions.

Responsive refactoring workflow with Claude Code

Imagine you're working on a dashboard UI with issues on smaller screens. Here's how Claude Code streamlines the process:

Audit the layout

review the layout.css file and highlight sections that break below 600px screen width

Suggest fixes — Claude Code responds with recommendations:
1. Replace width:600px with max-width:100%
2. Use flex-wrap:wrap in the .grid-container class

Apply changes safely — Claude Code uses its built-in text editor to apply only the approved diffs:

- .grid-container { display: flex; }
+ .grid-container { display: flex; flex-wrap: wrap; }

Verify output

does this new layout reduce overflow in mobile viewports?

Claude Code may propose an updated test suite using tools like Playwright or Cypress to simulate mobile rendering.

This cycle—detect, fix, verify—can be repeated for typography scaling, button responsiveness, and more. Claude Code's real-time project awareness eliminates the need for back-and-forth between browser dev tools and code editors, reducing debugging time by up to 50%.

Maintainability at scale

Responsive design is about resilience and scalability. Claude helps future-proof your codebase by:

Encouraging semantic HTML and accessibility compliance
Suggesting modern CSS techniques (like clamp(), aspect-ratio, and container queries)
Refactoring monolithic files into reusable components
Supporting automated testing of layout behavior across breakpoints

Whether you're maintaining a design system or shipping weekly product updates, Claude ensures your UI remains flexible, readable, and robust.

How Ramp uses Claude Code for responsive refactoring

Ramp, a leading spend management platform, uses Claude Code to optimize their web app's responsive behavior. By prompting Claude Code to audit and refactor layout styles, Ramp's engineering team reported:

40% reduction in CSS file size
60% fewer media query breakpoints
35% faster page load times on mobile devices

By catching responsive issues early and providing contextual fixes, Claude Code helps Ramp ship a better product faster.

Choosing the right Claude tool for the job

Both tools‍ offer unique benefits for responsive web design.

Claude.ai generates responsive boilerplate and supplies explanations and best practices. It works on web, desktop, and mobile, and it’s free.

Claude Code integrates with your local development environment, refactors existing codebases, and supports large-scale maintainability. It can be accessed through the terminal and requires API access or a Max plan subscription.

In general, use Claude.ai for rapid prototyping, learning, and experimentation. It's the fastest way to go from a blank canvas to a responsive foundation.

Switch to Claude Code when you need to integrate with your local repo, refactor production-scale layouts, or maintain a complex design system. Its agentic nature and deep integration with your codebase make it a powerful tool for front-end optimization.

Get started

Ready to streamline your responsive design process? Here's how to get started:

Visit Claude.ai and sign up for free. Use it to generate boilerplate code, learn best practices, and rapidly prototype responsive layouts.
When you're ready to refactor production-scale layouts, install Claude Code and invoke it from your terminal:

npm install -g @anthropic-ai/claude-code
cd your-project
claude

With Claude, you can finally create responsive designs with confidence. The result? Responsive web experiences delivered faster, with fewer bugs and less manual effort.