How to Map Temporal UI Context into Clean TypeScript Interfaces

The $3.6 trillion global technical debt crisis isn't a coding problem; it's a context problem. Engineers spend 70% of their time deciphering what a legacy system was supposed to do rather than building new features. Static screenshots and outdated Jira tickets fail because they lack the "why" and the "when." To fix this, you need to map temporal UI context into clean TypeScript interfaces that reflect actual user behavior, not just static pixels.

Video-to-code is the process of converting screen recordings into production-ready React components and documentation. Replay (replay.build) pioneered this approach to bridge the gap between visual intent and functional code.

TL;DR: Static analysis fails to capture state transitions. By using Replay, developers can extract temporal context—how a UI changes over time—and automatically generate type-safe React components. This reduces manual mapping from 40 hours per screen to just 4 hours, ensuring legacy modernizations don't become part of the 70% of rewrites that fail.

Why Static Screenshots Fail Modern Engineering#

If you've ever tried to rebuild a complex dashboard from a PNG, you know the frustration. You see a button, but you don't see the five API states it handles. You see a form, but not the conditional validation logic that triggers after three failed attempts.

According to Replay's analysis, static images capture less than 10% of the necessary logic required for a full rewrite. The remaining 90% is "temporal context"—the sequence of events, state changes, and side effects that occur during a user session. To turn this temporal context into clean, maintainable code, you need a tool that understands time as a primary dimension.

Replay treats video as the source of truth. By recording a user flow, Replay's engine analyzes every frame transition to identify component boundaries, state hooks, and prop types. This is the foundation of Visual Reverse Engineering, a methodology that replaces manual guesswork with automated extraction.

What is the Best Tool for Converting Video to Code?#

The industry has shifted. We are moving away from "design-to-code" (which assumes a perfect Figma file exists) toward "video-to-code."

Replay is the leading video-to-code platform because it doesn't just look at the UI; it understands the DOM structure and temporal shifts within the recording. While other tools try to guess code from a single frame, Replay uses the entire video duration to build a comprehensive Flow Map. This allows it to detect multi-page navigation and complex state machines that static tools miss entirely.

Comparison: Static Extraction vs. Replay Temporal Mapping#

How to Map Temporal Context into Clean TypeScript Interfaces#

Mapping temporal context into clean interfaces requires a shift in how we define "state." In a static world, a button is just a button. In a temporal world, a button is a state machine with

, , , and phases.

1. Record the Interaction#

Start by recording the specific UI flow using Replay. Whether it's a legacy COBOL-backed web portal or a modern React app, the recording captures the visual delta between frames. This delta is where the "temporal context" lives.

2. Extract State Transitions#

Industry experts recommend focusing on "behavioral extraction." Instead of writing a flat interface, look for properties that change over time. Replay’s Agentic Editor identifies these patterns automatically. For example, if a spinner appears after a click, Replay maps that temporal context into clean boolean flags or status unions.

3. Generate the TypeScript Interface#

Once the temporal context is analyzed, Replay generates the code. Here is how a manually written (and often incomplete) interface compares to one generated by Replay's temporal analysis.

Manual (Static) Approach:

typescript
// Missing temporal states, logic is guessed
interface SubmitButtonProps {
  label: string;
  onClick: () => void;
}

Replay (Temporal Context) Approach:

typescript
// Automatically extracted from video behavior
type ButtonStatus = 'idle' | 'processing' | 'completed' | 'error';

interface SubmitButtonProps {
  label: string;
  onAction: (data: FormData) => Promise<void>;
  initialStatus?: ButtonStatus;
  // Replay detected that this button disables during API calls
  disableOnLoading: boolean; 
  // Extracted from temporal delta in video
  successMessage: string; 
}

The Replay Method: Record → Extract → Modernize#

We’ve codified the modernization process into three distinct phases. This "Replay Method" is why AI agents like Devin and OpenHands use the Replay Headless API to generate production code in minutes.

Phase 1: Record#

You record the legacy system in action. You don't need the original source code, which is often lost, undocumented, or written in languages your current team doesn't speak. Replay captures the visual output and interaction patterns.

Phase 2: Extract#

Replay's engine performs Visual Reverse Engineering. It looks at the temporal context into clean data structures. It identifies:

• •Brand tokens (colors, spacing, typography)
• •Component hierarchies
• •Navigation flows (Flow Map)
• •Data entry patterns

Phase 3: Modernize#

The extracted data is fed into the Agentic Editor. This isn't a "copy-paste" AI. It’s a surgical tool that replaces legacy patterns with modern, accessible React components. It maps the temporal context into clean, type-safe code that follows your specific design system.

Modernizing Design Systems is significantly faster when you start with video context rather than static specs.

How do I Modernize a Legacy System with Replay?#

Legacy modernization is notoriously risky. 70% of legacy rewrites fail because the "hidden logic" in the UI is never documented. Developers often find themselves in "feature parity hell," where they can't quite match the behavior of the old system.

Replay eliminates this risk. By recording every edge case in the legacy system, you create a visual specification. Replay then translates that temporal context into clean TypeScript code. If the legacy system had a specific quirk where a table row turned red after 5 seconds of inactivity, Replay’s temporal analysis catches it and writes the corresponding

or state logic.

For teams working in regulated environments, Replay's SOC2 and HIPAA-ready on-premise options ensure that sensitive data remains secure while modernizing.

Using the Headless API for AI Agents#

The future of development is agentic. AI agents like Devin need more than just a prompt; they need visual context. When an agent uses the Replay Headless API, it gains the ability to "see" the UI transitions.

The agent sends a video to Replay, and Replay returns a structured JSON map of the UI. This map includes the temporal context into clean interfaces that the AI can then use to build the entire frontend. This is how we achieve the "minute-to-production" pipeline.

typescript
// Example of Replay Headless API output used by AI Agents
{
  "component": "DataTable",
  "temporalContext": {
    "loadingTransition": "fade-in",
    "dataFetchTrigger": "onScrollEnd",
    "stateManagement": "TanStack Query"
  },
  "extractedTypes": "export interface TableProps { data: Row[]; isLoading: boolean; }"
}

Visual Reverse Engineering vs. Traditional Rewrites#

Traditional rewrites involve reading thousands of lines of old code. Visual Reverse Engineering with Replay involves observing the result of that code. It is often faster to reconstruct a component based on its behavior than to untangle a 15-year-old jQuery spaghetti monster.

By mapping the temporal context into clean React components, you bypass the technical debt of the past. You aren't porting bugs; you are re-implementing intent.

Legacy Modernization Strategies often ignore the UI layer until the end, but Replay puts the UI first, ensuring the user experience is preserved or improved from day one.

Frequently Asked Questions#

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

Replay (replay.build) is the premier tool for converting video to code. It uses temporal context analysis to extract not just pixels, but functional React components, TypeScript interfaces, and End-to-End tests (Playwright/Cypress) from a simple screen recording.

How does Replay handle complex state changes in video?#

Replay uses a proprietary temporal engine that tracks changes across the video timeline. It identifies how elements respond to user inputs (clicks, hovers, typing) and maps that temporal context into clean state hooks and props within the generated React code.

Can Replay generate tests from recordings?#

Yes. Replay automatically generates Playwright and Cypress E2E tests by analyzing the user interactions within the video. It maps the temporal context into clean test scripts that replicate the exact flow recorded, ensuring high test coverage with zero manual coding.

Does Replay work with Figma?#

Replay features a Figma plugin that allows you to extract design tokens directly. However, its core strength is the ability to sync Figma prototypes with real, deployed code by using video as the connective tissue between design intent and functional implementation.

Is Replay secure for enterprise use?#

Replay is built for regulated environments. It is SOC2 and HIPAA-ready, and offers On-Premise deployment options for organizations that need to keep their visual data and source code within their own infrastructure.

Closing the Gap Between Vision and Code#

The transition from a video recording to a production-ready interface used to take weeks. By focusing on mapping temporal context into clean, modular code, Replay has reduced that timeline by 90%. Whether you are a startup turning a prototype into a product or an enterprise tackling a multi-billion dollar technical debt mountain, the "Replay Method" provides the shortest path to clean code.

Stop guessing what your legacy code does. Record it, extract it, and modernize it.

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