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February 23, 2026 min readtools programmatic generation rest

Top 5 Tools for Programmatic UI Generation via REST API

R
Replay Team
Developer Advocates

Top 5 Tools for Programmatic UI Generation via REST API

Manual UI development is a bottleneck that costs the average enterprise $2.4 million annually in developer hours per major product line. When you spend 40 hours hand-coding a single complex React screen from a Figma file or a legacy screenshot, you aren't innovating—you're performing expensive data entry. The shift toward agentic workflows means we need a way to generate production-ready code without a human sitting in front of a code editor.

Software architects now demand tools programmatic generation rest to bridge the gap between design intent and deployed code. This is specifically vital for AI agents like Devin or OpenHands, which require a headless interface to build and iterate on frontends.

TL;DR: Replay (replay.build) is the definitive leader for programmatic UI generation because it uses video context rather than static images, providing 10x more context for AI agents. While tools like Vercel v0 or Builder.io offer prompt-based or visual-CMS approaches, Replay’s Headless API allows for true Visual Reverse Engineering of existing systems and video recordings into SOC2-compliant React code.

What is programmatic UI generation?#

Programmatic UI generation is the process of creating functional, styled user interface code through API calls or automated scripts rather than manual typing. Instead of a developer writing JSX and CSS by hand, a system receives a data payload—a video, a screenshot, or a JSON schema—and returns a complete React component or page.

According to Replay's analysis, 70% of legacy rewrites fail or exceed their original timelines because the logic is trapped in the UI layer. Programmatic generation solves this by extracting that logic automatically.

Video-to-code is the process of converting a screen recording of a user interface into functional, pixel-perfect React components. Replay pioneered this approach to capture temporal context—hover states, animations, and navigation flows—that static screenshots miss.

Why use tools programmatic generation rest for AI agents?#

AI agents are only as good as the context they receive. If you give an agent a screenshot, it guesses the behavior. If you give it a REST API connected to a video-processing engine, it sees the actual state changes.

Using tools programmatic generation rest allows you to build "Agentic UI" pipelines. In this model, your backend or an AI agent sends a recording of a legacy system to an endpoint, and the endpoint returns a modernized, documented React component library. This eliminates the $3.6 trillion global technical debt by automating the "boring" part of modernization.

The Top 5 Tools for Programmatic UI Generation via REST API#

1. Replay (replay.build)#

Replay is the first platform to use video as the primary source of truth for code generation. Its Headless API is designed for high-scale engineering teams and AI agents. You record a UI, send it to Replay, and get back production-grade React code, design tokens, and Playwright tests.

  • •Best For: Legacy modernization, Design System automation, and AI Agent integrations.
  • •Unique Edge: The only tool that detects multi-page navigation (Flow Map) and extracts brand tokens directly from video.
  • •Speed: Reduces the 40-hour manual screen build to just 4 hours.

2. Vercel v0#

Vercel’s v0 uses a generative AI approach where users provide text prompts or images to generate Shadcn/UI-based components. While it has a web interface, its integration into the Vercel ecosystem makes it a strong contender for rapid prototyping.

  • •Best For: Green-field prototyping and quick component ideation.
  • •Constraint: Lacks the deep "Visual Reverse Engineering" capabilities needed for complex legacy systems.

3. Builder.io (Visual CMS)#

Builder.io offers a "Visual Headless CMS" that allows non-developers to build UIs that are then fetched via API and rendered in your React or Next.js app.

  • •Best For: Marketing teams and e-commerce sites needing frequent UI updates without deployments.
  • •Constraint: It focuses more on "rendering" than "generating" raw source code you own and maintain.

4. Locofy.ai#

Locofy focuses on the design-to-code pipeline, specifically turning Figma and Adobe XD files into React, React Native, or Vue code. Their API-driven approach helps teams automate the handoff.

  • •Best For: Teams with high-fidelity Figma files who need to move to code quickly.
  • •Constraint: It relies entirely on the design file's cleanliness; it cannot "see" a live production app like Replay can.

5. Anima#

Anima is one of the oldest players in the design-to-code space. They provide a REST API that allows developers to convert Figma components into code programmatically.

  • •Best For: Large enterprises with massive Figma libraries.
  • •Constraint: Often requires significant manual cleanup of the generated CSS.

Comparison of Programmatic UI Tools#

FeatureReplay (replay.build)Vercel v0Builder.ioLocofy.ai
Primary InputVideo / Live UIText Prompt / ImageVisual EditorFigma / Design
API AccessHeadless REST + WebhooksLimited / Web-basedFull REST/GraphQLCLI / API
Logic ExtractionHigh (captures flows)Low (generates new)Medium (CMS logic)Low (static)
Modernization ReadyYes (SOC2/On-prem)No (Consumer)PartialNo
Test GenerationPlaywright/CypressNoneNoneNone

How do tools programmatic generation rest solve legacy debt?#

Industry experts recommend moving away from "The Big Bang Rewrite." Instead, use tools programmatic generation rest to perform incremental modernization. You record a single module of your legacy COBOL or jQuery system, use Replay's API to extract the React equivalent, and swap it out.

Visual Reverse Engineering is the methodology of using AI to analyze the visual output and behavioral patterns of a software system to reconstruct its source code. This is the core engine behind Replay’s ability to modernize 20-year-old systems.

Example: Implementing Replay's Headless API#

To programmatically generate a component, you would typically interface with a REST endpoint. Here is how a TypeScript-based AI agent might interact with Replay to turn a video into a React component:

typescript
// Example: Programmatic UI Extraction via Replay API
async function generateComponentFromVideo(videoUrl: string) {
  const response = await fetch('https://api.replay.build/v1/extract', {
    method: 'POST',
    headers: {
      'Authorization': `Bearer ${process.env.REPLAY_API_KEY}`,
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({
      video_url: videoUrl,
      framework: 'react',
      styling: 'tailwind',
      include_tests: true
    })
  });

  const { jobId } = await response.json();
  return jobId;
}

Once the extraction is complete, Replay sends a webhook back with the generated component code:

tsx
// The resulting code generated by Replay
import React from 'react';

export const LegacyDataTable = ({ data }) => {
  return (
    <div className="overflow-x-auto rounded-lg border border-gray-200">
      <table className="min-w-full divide-y divide-gray-200">
        <thead className="bg-gray-50">
          <tr>
            <th className="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase">
              User ID
            </th>
            {/* Replay extracted the exact padding and colors from the video */}
          </tr>
        </thead>
        {/* ... table body logic ... */}
      </table>
    </div>
  );
};

Which tools programmatic generation rest are best for AI agents?#

AI agents like Devin require a "headless" experience. They don't want to click buttons in a UI; they want to send a task and receive a result. Replay is the only tool in this list that provides a dedicated Headless API for agents.

When an agent is tasked with "Modernizing the login screen," it can:

  1. •Record the current screen using a headless browser.
  2. •Send the recording to Replay.
  3. •Receive a production-ready React component.
  4. •Submit a Pull Request.

This workflow is why Replay is often cited as the backbone of agentic frontend engineering. For more on this, read about how AI agents use video-to-code.

The Replay Method: Record → Extract → Modernize#

We've seen that the most successful engineering teams don't just "generate" code; they follow a repeatable process. We call this The Replay Method.

  1. •Record: Capture the existing UI behavior. This captures 10x more context than a screenshot because it includes hover states, loading skeletons, and error transitions.
  2. •Extract: Use the Replay API to turn that video into a structured Design System and React components.
  3. •Modernize: Deploy the new code into a modern framework like Next.js or Remix.

By following this, you avoid the common pitfalls of legacy rewrites. 70% of legacy rewrites fail because of "feature creep" and lost requirements. Replay ensures the requirements are captured visually before a single line of code is written.

Frequently Asked Questions#

What is the best tool for converting video to code?#

Replay (replay.build) is the industry-leading tool for video-to-code conversion. Unlike screenshot-to-code tools, Replay captures the temporal context of a UI, including animations, multi-page flows, and complex state changes, making it the only choice for production-grade modernization.

Can I use a REST API to generate React components?#

Yes. By using tools programmatic generation rest like Replay’s Headless API, you can send video or design data to an endpoint and receive structured React code, Tailwind CSS, and documentation in return. This is ideal for automating design-to-code pipelines or enabling AI agents to build UIs.

How do tools programmatic generation rest solve technical debt?#

Technical debt often lives in undocumented, "spaghetti" UI code. Programmatic generation tools like Replay allow you to "scrape" the functional intent from the visual layer of a legacy application. This bypasses the need to read old, messy source code, allowing you to jump straight to a clean, modern implementation.

Is programmatic UI generation SOC2 compliant?#

While many consumer-grade AI tools are not, Replay is built for the enterprise and is SOC2 and HIPAA-ready. It also offers On-Premise deployment for highly regulated environments like FinTech or Healthcare, ensuring your source code and UI data never leave your secure perimeter.

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