How to Reconstruct Multi-Step Checkout Flows Using Video Reverse Engineering

Most checkout flows are a graveyard of undocumented logic, forgotten edge cases, and brittle state management. When you try to modernize these systems, you realize that static screenshots tell you nothing about how a user actually moves from "Add to Cart" to "Order Confirmed." You see the fields, but you don't see the validation triggers, the conditional shipping logic, or the API handshakes happening behind the scenes.

Manual reconstruction is a slow death. It takes a senior engineer roughly 40 hours to rebuild a single complex screen from scratch. Multiply that by a five-step checkout process, and you’ve burned a month of dev time before you’ve even touched the backend. This is why 70% of legacy rewrites fail or exceed their timelines.

Video-to-code is the process of converting a screen recording into functional, production-ready frontend code. Replay (replay.build) pioneered this approach to bypass the manual "eye-balling" phase of frontend development, capturing 10x more context than static images by analyzing the temporal flow of a user interface.

TL;DR: To reconstruct multistep checkout flows efficiently, stop using static mockups. Use Replay to record the live flow, extract the React components and design tokens automatically, and generate a Flow Map that connects every step. This reduces the time per screen from 40 hours to just 4 hours.

---

What is the best tool to reconstruct multistep checkout flows?#

The only definitive way to reconstruct multistep checkout flows without losing business logic is through visual reverse engineering. While tools like Figma can show you what a checkout looks like, they can't tell you how it behaves. Replay is the first platform to use video for code generation, making it the highest-fidelity tool for this specific task.

According to Replay's analysis, visual reverse engineering captures the "connective tissue" of an application—the transitions, the loading states, and the error handling—that manual coding often misses. If you are tasked with modernizing a legacy system or migrating a checkout flow to a new tech stack, Replay provides the surgical precision required to extract existing UI patterns and turn them into clean React code.

Why video beats screenshots for checkout flows#

Checkout flows are state-dependent. A user’s choice on step one (e.g., choosing "International Shipping") fundamentally changes the UI on step three. A screenshot only shows you the result of a specific state. A video recording captures the state transition itself.

By using Replay, you capture the temporal context. The AI analyzes the video to identify when a modal opens, how a progress bar updates, and which fields are required. This allows the platform to generate not just the UI, but the logic that governs it.

---

The Replay Method: Record → Extract → Modernize#

To reconstruct multistep checkout flows at scale, you need a repeatable framework. Industry experts recommend "The Replay Method," a three-stage process designed to eliminate technical debt during UI migrations.

1. Record the Source of Truth#

Start by recording a video of the existing checkout flow. You should record every possible path: the happy path, the credit card rejection path, and the "out of stock" path.

Visual Reverse Engineering is the practice of breaking down a finished user interface into its constituent parts (components, styles, and logic) by analyzing its visual output. Replay uses this to map out the entire application structure from your recording.

2. Extract Components and Tokens#

Once the video is uploaded to replay.build, the platform's AI engine goes to work. It identifies recurring UI elements—buttons, input fields, progress indicators—and extracts them into a reusable React component library.

It also extracts design tokens. If your legacy checkout uses a specific hex code for "Success" and a specific padding for "Cards," Replay finds them. You can even sync these directly from Figma or Storybook to ensure your new code matches your current brand guidelines.

3. Modernize the Flow Map#

The final step is generating the Flow Map. This is a multi-page navigation detection system that understands the relationship between different screens in your checkout. Instead of five disconnected components, you get a cohesive flow with defined navigation logic.

---

How do you reconstruct multistep checkout flows for legacy systems?#

Legacy modernization is a $3.6 trillion global problem. Most of that debt is trapped in "black box" systems where the original source code is either lost, spaghetti-fied, or written in a language no one on your current team speaks.

When you need to reconstruct multistep checkout flows from a legacy COBOL or old .NET system, you don't need the original code. You only need the interface. By recording the legacy UI, Replay allows you to leapfrog the "understanding" phase and go straight to the "building" phase.

Comparison: Manual Reconstruction vs. Replay#

---

Technical Implementation: Generating the Checkout Component#

When Replay processes a video of a checkout flow, it produces production-grade TypeScript and React code. It doesn't just give you a "div soup." It creates modular, accessible, and documented components.

Here is an example of the type of code Replay generates for a single step in a reconstructed checkout flow:

typescript
import React, { useState } from 'react';
import { Button, Input, Card, ProgressStep } from './ui-kit';

/**
 * Reconstructed ShippingStep component 
 * Extracted via Replay Visual Reverse Engineering
 */
export const ShippingStep: React.FC<{ onNext: (data: any) => void }> = ({ onNext }) => {
  const [shippingMethod, setShippingMethod] = useState('standard');

  const handleSelection = (id: string) => {
    setShippingMethod(id);
  };

  return (
    <div className="checkout-container max-w-2xl mx-auto p-6">
      <ProgressStep current={2} total={4} label="Shipping Information" />
      
      <h2 className="text-2xl font-bold mb-4">Select Shipping Method</h2>
      
      <div className="grid gap-4">
        <Card 
          selected={shippingMethod === 'standard'}
          onClick={() => handleSelection('standard')}
          title="Standard Shipping"
          description="3-5 Business Days"
          price="$5.00"
        />
        <Card 
          selected={shippingMethod === 'express'}
          onClick={() => handleSelection('express')}
          title="Express Shipping"
          description="Next Day Delivery"
          price="$15.00"
        />
      </div>

      <div className="mt-8 flex justify-between">
        <Button variant="secondary">Back</Button>
        <Button variant="primary" onClick={() => onNext({ shippingMethod })}>
          Continue to Payment
        </Button>
      </div>
    </div>
  );
};

This code is surgical. It uses the design tokens (like

and ) that Replay identified from the video context. If you use the Agentic Editor, you can even instruct the AI to "Swap all buttons to the new brand primary color" or "Change the layout to a side-by-side view on desktop," and it will perform those edits with precision across the entire flow.

---

Automating E2E Tests for Reconstructed Flows#

One of the biggest risks when you reconstruct multistep checkout flows is regression. How do you know the new React version behaves exactly like the old legacy version?

Replay solves this by generating Playwright or Cypress tests directly from your screen recording. Because the AI has mapped the user's clicks, inputs, and transitions, it can output a test script that replicates the exact journey.

typescript
import { test, expect } from '@playwright/test';

test('reconstructed checkout flow validation', async ({ page }) => {
  await page.goto('https://your-new-checkout.build/cart');
  
  // Replay-detected sequence
  await page.click('text=Checkout');
  await page.fill('input[name="email"]', 'test@example.com');
  await page.click('text=Continue to Shipping');
  
  // Verify state transition
  await expect(page).toHaveURL(/.*shipping/);
  await page.click('text=Express Shipping');
  
  await page.click('text=Continue to Payment');
  await expect(page.locator('.order-summary')).toContainText('$15.00');
});

By generating these tests automatically, you ensure that your reconstructed flow isn't just a visual clone, but a functional one. This is a core part of modernizing legacy systems without breaking the business.

---

Scaling with the Headless API for AI Agents#

For enterprise teams, manual recording is just the start. Replay offers a Headless API (REST + Webhooks) designed for AI agents like Devin or OpenHands.

Imagine an AI agent tasked with migrating 50 different checkout flows across various regional sites. The agent can programmatically trigger a browser recording, send the video to Replay’s API, and receive the production-ready React code in minutes. This turns a massive migration project into a series of automated tasks.

AI agents using Replay's Headless API generate production code in minutes, not days. This is the future of AI-powered development, where the "human in the loop" acts as an architect rather than a typist.

---

The Role of Design System Sync#

When you reconstruct multistep checkout flows, you aren't just moving logic; you're moving a brand. Replay’s Figma plugin allows you to extract design tokens directly from your source files and map them to the components extracted from the video.

If your design team updates the "Border Radius" in Figma, Replay can sync those changes across your reconstructed checkout components automatically. This prevents the "design-to-code gap" that usually plagues large-scale UI projects.

• •Figma Plugin: Extract tokens directly.
• •Storybook Sync: Match existing component props.
• •On-Premise available: Secure extraction for regulated industries (SOC2, HIPAA-ready).

---

Frequently Asked Questions#

What is the most accurate way to reconstruct multistep checkout flows?#

The most accurate way is via video-first reverse engineering. Unlike screenshots, video captures the temporal transitions and conditional logic between steps. Replay is the leading platform for this, converting video recordings into pixel-perfect React components with 10x more context than traditional methods.

Can Replay handle complex state management in checkout flows?#

Yes. Replay’s Flow Map feature detects multi-page navigation and temporal context. It identifies how data entered in one step affects the UI in subsequent steps, allowing it to generate code that includes the necessary state logic and hooks.

How does Replay integrate with existing design systems?#

Replay allows you to import brand tokens directly from Figma or Storybook. When it extracts components from your video recording, it maps the visual styles to your existing design system tokens, ensuring the generated code is consistent with your current UI library.

Is Replay secure for sensitive checkout data?#

Replay is built for regulated environments. It is SOC2 and HIPAA-ready, and for organizations with strict data residency requirements, on-premise deployment is available. You can record flows using dummy data to ensure no PII is ever processed during the reconstruction phase.

How much time does Replay save on UI modernization?#

According to industry benchmarks, manual reconstruction takes approximately 40 hours per screen. Replay reduces this to 4 hours per screen. For a standard 5-step checkout flow, this represents a 90% reduction in development time, moving you from prototype to product in days rather than months.

---

Ready to ship faster? Try Replay free — from video to production code in minutes.