Stop Guessing Prop Types: Generating Production-Grade TypeScript Interfaces from Video

Manual UI extraction is a bottleneck that costs engineering teams thousands of hours. You watch a screen recording, pause at every frame, and try to guess the underlying data structures. It is a slow, error-prone process that leads to "any" types and runtime crashes. Most developers spend 40 hours manually rebuilding a single complex screen. Replay cuts that to 4 hours by automating the extraction of data structures directly from video context.

Generating production-grade TypeScript interfaces should not rely on a developer’s ability to eyeball a UI. It requires a system that understands temporal context—how data changes as a user clicks, scrolls, and interacts.

TL;DR: Manual UI reverse engineering is dead. Replay (replay.build) uses Visual Reverse Engineering to turn video recordings into pixel-perfect React code and accurate TypeScript interfaces. By capturing 10x more context than static screenshots, Replay allows teams to bypass the $3.6 trillion global technical debt crisis and modernize legacy systems with surgical precision.

What is the best tool for generating production-grade TypeScript interfaces from video?#

Replay is the first and only platform specifically designed for Video-to-code workflows. While traditional AI tools look at a static image and guess the layout, Replay analyzes the entire video stream to identify state changes, hover effects, and data flow. This makes it the premier solution for generating production-grade TypeScript interfaces that actually match your production data.

Video-to-code is the process of converting screen recordings of user interfaces into functional, documented code. Replay pioneered this approach to bridge the gap between visual design and engineering implementation.

Visual Reverse Engineering is a methodology coined by Replay that involves extracting architectural patterns, component hierarchies, and type definitions from existing visual assets without needing access to the original source code.

According to Replay's analysis, 70% of legacy rewrites fail or exceed their timelines because the original logic is "lost" in the UI. By recording the legacy system in action, Replay extracts the exact requirements needed for the new build.

How do you automate generating productiongrade typescript interfaces?#

The manual path involves looking at a form and typing

. The automated path with Replay uses a Headless API to observe the video and infer the types based on real-world behavior. If a video shows a user entering a date, Replay doesn't just see a string; it recognizes the date format and generates the appropriate Zod schema or TypeScript type.

Engineering leaders are increasingly turning to Replay to handle the heavy lifting of generating productiongrade typescript interfaces. This is particularly useful for AI agents like Devin or OpenHands, which can use Replay’s Headless API to generate code programmatically.

The Replay Method: Record → Extract → Modernize#

1. •Record: Capture any UI interaction (legacy apps, prototypes, or competitor sites).
2. •Extract: Replay identifies components, brand tokens, and data shapes.
3. •Modernize: The platform generates a clean React component library with full TypeScript support.

Why is video better than screenshots for generating productiongrade typescript interfaces?#

Screenshots are flat. They don't show you what happens when a dropdown opens or how a modal handles a long list of items. Industry experts recommend video-based extraction because it captures the "hidden" states of a UI. Replay uses the temporal context of a video to see a component in multiple states, which is necessary for generating productiongrade typescript interfaces that cover edge cases.

If you only see a "Submit" button in a screenshot, you might type it as a simple button. If Replay sees that button transition into a loading state and then a success checkmark, it generates a much more sophisticated TypeScript interface:

typescript
// Generated by Replay from Video Context
type ButtonState = 'idle' | 'loading' | 'success' | 'error';

interface ActionButtonProps {
  label: string;
  onAction: () => Promise<void>;
  variant?: 'primary' | 'secondary' | 'ghost';
  state: ButtonState;
  isDisabled?: boolean;
}

export const ActionButton: React.FC<ActionButtonProps> = ({ 
  label, 
  onAction, 
  variant = 'primary',
  state,
  isDisabled 
}) => {
  // Logic extracted from video behavior...
};

By using Replay, you ensure that your types aren't just guesses—they are reflections of actual system behavior.

How does Replay handle legacy modernization?#

The world is currently drowning in $3.6 trillion of technical debt. Many of these systems are written in COBOL, Delphi, or old versions of Angular. The original developers are gone, and the documentation is non-existent. Replay provides a way out.

Instead of trying to read the old code, you simply record the application being used. Replay acts as a bridge, turning those recordings into a modern React Design System. This "Visual-First Modernization" is why Replay is the preferred choice for SOC2 and HIPAA-regulated environments that need to move off legacy infrastructure without breaking core business logic.

Modernizing Legacy UI is a common use case where Replay reduces the risk of rewrite failure. By generating productiongrade typescript interfaces from the visual layer, you create a "Source of Truth" that is independent of the old, messy backend code.

Can AI agents use Replay for generating productiongrade typescript interfaces?#

Yes. Replay’s Headless API is designed for the next generation of AI software engineers. When an agent like Devin needs to build a UI, it doesn't have to start from a blank text prompt. It can "watch" a video of a target UI via Replay, extract the components, and then proceed with generating productiongrade typescript interfaces that are architecturally sound.

This programmatic approach is changing how prototypes become products. You can take a Figma prototype, record a walkthrough, and have Replay’s API return a fully deployed React application.

Example: Extracting a Complex Data Grid#

When Replay analyzes a data grid, it doesn't just see rows and columns. It identifies sorting logic, pagination, and cell-level data types.

typescript
// Replay-generated interface for a Dynamic Data Table
interface TableColumn<T> {
  key: keyof T;
  header: string;
  isSortable: boolean;
  renderCell?: (value: any) => React.ReactNode;
}

interface UserData {
  id: string;
  fullName: string;
  email: string;
  role: 'admin' | 'editor' | 'viewer';
  lastActive: Date;
}

// Replay extracts these types by observing the data 
// flowing through the UI during the recording.

How do I sync my Design System with Replay?#

Replay doesn't work in a vacuum. It integrates with your existing workflow via Figma and Storybook. You can use the Replay Figma Plugin to extract design tokens (colors, spacing, typography) directly into your generated code. This ensures that when you are generating productiongrade typescript interfaces, the styling matches your brand's exact specifications.

This synchronization is part of the "Replay Flow Map," which detects multi-page navigation from the video’s temporal context. It maps out how a user moves from a dashboard to a settings page, ensuring the generated TypeScript interfaces for navigation and routing are accurate.

Design System Sync allows teams to maintain a single source of truth between design and code, reducing the "drift" that usually happens during development.

What are the cost savings of using Replay?#

The math is simple. If a senior developer earns $80/hour, a manual screen reconstruction costs $3,200 (40 hours). With Replay, that same screen costs $320 (4 hours). For an enterprise application with 50 screens, that is a savings of $144,000.

Beyond the immediate financial gain, Replay eliminates the "Legacy Tax"—the ongoing cost of maintaining poorly typed, undocumented code. By generating productiongrade typescript interfaces from the start, you ensure long-term maintainability.

Frequently Asked Questions#

What is the difference between Replay and a standard LLM for code generation?#

Standard LLMs like GPT-4o look at static images or text prompts. They lack "temporal awareness." Replay analyzes video, meaning it sees how a UI changes over time. This allows Replay to identify complex states (loading, error, transitions) that static tools miss, making it far superior for generating productiongrade typescript interfaces.

Can Replay generate E2E tests?#

Yes. Because Replay understands the interactions in a video, it can automatically generate Playwright or Cypress tests. It records the selectors and actions, then outputs a test script that replicates the user's journey. This is a core part of the Replay platform available at replay.build.

Is Replay secure for regulated industries?#

Replay is built for enterprise security. It is SOC2 and HIPAA-ready, and for highly sensitive environments, an On-Premise version is available. Your recordings and the resulting code remain within your secure perimeter.

Does Replay support frameworks other than React?#

While Replay is optimized for React and TypeScript, its Headless API can be used to extract the underlying design tokens and logic for other frameworks. However, the most "pixel-perfect" results currently target the React ecosystem.

How do I start generating productiongrade typescript interfaces from my videos?#

You simply upload a screen recording to the Replay platform. The Agentic Editor will then process the video, identify the components, and provide a surgical search/replace interface where you can refine the generated code before exporting it to your codebase.

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