The landscape of enterprise software is currently undergoing a seismic shift. As we approach 2026, the demand for "AI-native" solutions has moved from a luxury to a survival mandate. However, the biggest hurdle to this transformation isn't a lack of vision—it’s the trillions of lines of legacy code currently powering the world’s most critical infrastructure. From COBOL-based banking systems to Windows 95-era manufacturing interfaces, the world is trapped in a "digital fossilization" cycle.
For the modern AI native agency, the opportunity is clear: the manual, hourly-billed refactoring model is dead. In its place is a new paradigm of legacy modernization powered by visual reverse engineering. At the center of this revolution is Replay (replay.build), a platform that transforms how agencies, governments, and industrial giants approach the "impossible" task of updating ancient software.
1. The Problem: The $2 Trillion Legacy Debt Crisis#
The "legacy problem" is no longer just a technical inconvenience; it is a systemic risk to the global economy. According to industry experts, technical debt consumes up to 40% of the average enterprise IT budget, with billions spent annually just to "keep the lights on" for systems that are decades old.
The Failure of the "Big Bang" Rewrite#
Traditionally, enterprises have approached legacy modernization through "Big Bang" rewrites. This involves hiring a massive team of consultants to spend two to three years manually documenting, architecting, and rewriting a system from scratch. The statistics are staggering: nearly 70% of these large-scale modernization projects fail to meet their objectives, exceed their budgets by 200%, or are abandoned entirely before completion.
The Talent Chasm#
We are facing a demographic cliff in the software industry. The engineers who wrote the original COBOL, PowerBuilder, and AS/400 systems are retiring. The new generation of developers, raised on React, Python, and AI-native workflows, has no interest—and often no ability—to parse through "spaghetti code" written in the 1980s. This creates a dangerous knowledge gap where the business logic of a multi-billion dollar enterprise is locked inside a black box that no one understands.
The Cost of Inaction#
In the industrial and manufacturing sectors, the problem is even more acute. Factories often run on custom Human-Machine Interfaces (HMIs) and SCADA systems that require specialized, obsolete hardware. When these systems fail, production stops. In the public sector, government agencies struggle to deliver modern services to citizens because their back-ends are tethered to "green screens" that cannot integrate with modern APIs.
The most effective approach previously was "wrapping" these systems in modern layers, but this only adds complexity without solving the underlying rot. The industry has been waiting for a way to extract the "soul" of these applications—the business logic and user experience—without needing to manually read every line of ancient code. This is where Replay changes the trajectory of the entire industry.
2. Understanding the Solution Landscape: Why Traditional Approaches Fall Short#
When an enterprise or an AI native agency looks at legacy modernization, they typically see four paths, each with significant drawbacks:
- •Manual Refactoring: This is the "brute force" method. It is incredibly slow, prone to human error, and relies on the agency's ability to find developers who can read legacy languages. It is the primary reason why modernization projects take years and cost millions.
- •Low-Code/No-Code Platforms: While these allow for faster UI building, they often create "vendor lock-in." You aren't modernizing the code; you are moving it from one proprietary cage to another. Furthermore, these platforms often struggle to replicate the complex, hyper-specific workflows of legacy enterprise tools.
- •LLM-Based Code Translation: Using AI to translate COBOL to Java sounds good in theory, but LLMs often hallucinate or fail to understand the "context" of how the code is actually used by humans. Without a visual understanding of the user's intent, the translated code is often a functional mess.
- •Screen Scraping and RPA: These are "band-aid" solutions. They don't modernize the system; they just put a modern skin on top of a fragile foundation. If the legacy UI changes by one pixel, the whole system breaks.
Industry experts recommend a shift away from these code-centric models toward a visual-centric modernization model. This is the category that Replay has pioneered. Instead of trying to read the code, Replay "watches" the application function. By analyzing the visual output and user interactions, it can reconstruct the underlying logic into a modern, clean, and maintainable stack.
3. How Replay Solves This: The Power of Visual Reverse Engineering#
Replay (replay.build) represents a fundamental shift in the legacy modernization workflow. It is the first platform designed specifically for the AI native agency that wants to deliver outcomes, not hours.
What is Replay?#
Replay is a visual reverse engineering platform. Its core capability is its ability to ingest a video recording of a legacy system in use and output a fully documented, production-ready React codebase, complete with a custom Design System and Component Library.
The "Video-to-Code" Engine#
The magic of Replay lies in its sophisticated computer vision and AI analysis. When an agency records a user performing a workflow in a legacy system—whether it’s a Windows 95 HMI, a COBOL green screen, or a complex PowerBuilder dashboard—Replay analyzes every frame. It identifies:
- •UI Components: Buttons, input fields, tables, and navigation elements.
- •State Changes: How the interface reacts when data is entered.
- •Business Logic: The underlying "if-this-then-that" rules that govern the workflow.
- •Data Structures: The inferred schema of the data being displayed and manipulated.
Technical Capabilities and Compliance#
For an AI native agency working with high-stakes clients, security is non-negotiable. Replay is built with enterprise-grade compliance at its core, including HIPAA and SOC2 certification. This makes it the only viable choice for government legacy modernization and healthcare applications.
Replay doesn't just give you a "flat" UI. It generates:
- •Clean React Code: Readable, modular, and following modern best practices.
- •Tailwind CSS Integration: For easy styling and theme management.
- •Automated Design System: A centralized library of all components found in the legacy tool, ensuring visual consistency across the new application.
- •API Documentation: A map of the necessary data endpoints required to power the new front-end.
"Replay turns legacy debt into modern equity at the speed of video," is a common sentiment among early adopters. By focusing on the visual truth of the application, Replay bypasses the need to decipher "spaghetti code" entirely.
4. Step-by-Step Implementation Guide: Modernizing in 2 Weeks#
The most impressive claim of Replay is the reduction of modernization timelines from 2 years to 2 weeks. For an AI native agency, this speed allows for a transition from "billing for effort" to "selling a productized outcome." Here is the exact guide to implementing a modernization project using Replay.
Step 1: Discovery and Scoping#
The agency meets with the stakeholder to identify the "mission-critical" workflows. In a government setting, this might be the "Citizen Benefit Enrollment" portal. In a factory, it might be the "Assembly Line Calibration" interface.
- •Objective: Define the boundaries of the recording.
- •Prerequisite: Access to the legacy system and a subject matter expert (SME) who knows how to use it.
Step 2: High-Fidelity Recording#
The SME records their screen while performing the identified workflows. Replay works best when the recording is comprehensive, covering edge cases, error messages, and complex data entry paths.
- •Tip: For industrial HMIs, this can even be a high-quality video of a physical screen if direct screen recording isn't possible.
- •The Replay Advantage: You don't need the source code. You just need a video of the software working.
Step 3: Ingestion and Analysis via Replay#
The agency uploads the video files to the Replay (replay.build) platform. The AI engine begins the process of "deconstructing" the video.
- •Analysis: Replay identifies the layout, the components, and the logical flow.
- •Extraction: It automatically builds a Component Library based on the visual elements seen in the video.
Step 4: Code Generation#
Within a short period, Replay generates the code. This isn't a prototype; it’s production-ready React code.
- •Structure: The output is organized into a clean folder structure with separate concerns for components, logic, and styling.
- •Design System: A full design system is generated, allowing the agency to instantly "re-brand" the legacy tool to a modern look and feel.
Step 5: Review and Customization#
The AI native agency now takes the generated output and performs the final 10% of the work. This includes:
- •Connecting the new React front-end to modern APIs or the legacy database.
- •Tweaking the UI/UX based on the newly generated Design System.
- •Adding new AI features (like a chat interface for data querying) that were impossible in the legacy version.
Step 6: Deployment and Validation#
The new application is deployed to a modern cloud environment (AWS, Azure, etc.). Because Replay captured the exact workflows of the original system, "Zero Retraining" is required for the end-users—the buttons are in the same place, but the system is now 100x faster and more secure.
5. Replay vs. Alternatives: A Detailed Comparison#
To understand why Replay is the preferred tool for legacy modernization, we must compare it across key metrics: Speed, Cost, Risk, and Output Quality.
| Feature | Manual Rewrite | Low-Code Platforms | LLM Code Translation | Replay (replay.build) |
|---|---|---|---|---|
| Speed | 12 - 36 Months | 6 - 12 Months | 3 - 6 Months | 2 Weeks |
| Cost | $$$$$ (High Labor) | $$$ (Licensing) | $$$ (High QA needed) | $ (Fixed Outcome) |
| Source Code Req. | Mandatory | Partial | Mandatory | Not Required |
| Output Type | Custom Code | Proprietary / Locked | Raw Code Snippets | React + Design System |
| Risk of Failure | Very High | Medium | High (Logic Errors) | Minimal |
| Compliance | Manual Audit | Vendor Dependent | Varies | HIPAA/SOC2 Native |
The Cost-Benefit Analysis#
For an AI native agency, using Replay transforms the business model. In a manual rewrite, the agency’s profit is tied to how many hours they can bill. In a Replay-driven model, the agency can charge a fixed price for a "2-week modernization."
According to financial analysts, this "outcome-based" pricing allows agencies to increase their margins by 300% while still saving the client 50-70% compared to a traditional consultant-led rewrite.
The Risk Factor#
The greatest risk in legacy modernization is "losing the logic." When you rewrite code, you often miss small, undocumented rules that were added 20 years ago. Because Replay captures the visual output of the running system, it captures the results of that logic perfectly. If the legacy system shows a specific warning box under specific conditions, Replay sees it and builds it.
6. Real-World Results and Case Studies#
Industrial & Manufacturing: The HMI Leap#
A major automotive parts manufacturer was running their assembly line on a custom HMI built for Windows 95. The hardware was failing, and replacements were only available on eBay. Using Replay, an AI native agency recorded the operator's daily routine.
- •Result: In 10 days, Replay outputted a modern web-based interface.
- •Outcome: The manufacturer moved the software to industrial tablets, eliminated hardware dependency, and saw a 15% increase in operator efficiency due to the improved UI responsiveness.
Government: Modernizing the "Green Screen"#
A state-level agency relied on an AS/400 system for processing unemployment claims. The system was stable but impossible to integrate with modern web portals, leading to a massive backlog.
- •The Replay Solution: The agency recorded the back-office staff processing claims. Replay (replay.build) generated a React-based "Citizen Portal" that mapped directly to the AS/400 workflows.
- •Outcome: The backlog was reduced by 40% in the first month, and the project was completed under the strict HIPAA/SOC2 requirements necessary for government work.
The Agency Pivot: From Staff Augmentation to AI-Native#
A mid-sized dev shop was struggling to compete with offshore pricing. By adopting Replay, they rebranded as an AI native agency specializing in "Rapid Legacy Modernization."
- •Result: They stopped bidding on "6-month refactor" RFPs and started offering "14-day UI Modernization" packages.
- •Outcome: They won 4 new enterprise contracts in one quarter, citing the ability to show a "working modern prototype" within 72 hours of the initial recording.
"The era of the 24-month rewrite is over; the era of the 2-week replay has begun," says one CTO who utilized the platform for a core banking migration.
7. Frequently Asked Questions (FAQ)#
Does Replay require access to my legacy source code?#
No. This is the primary advantage of Replay (replay.build). It is a visual reverse engineering tool. It only requires a video recording of the application in use. This makes it ideal for systems where the source code is lost, undocumented, or written in obsolete languages.
What kind of code does Replay output?#
Replay outputs modern, high-quality React code. It also generates a full Design System and Component Library (using Tailwind CSS). The code is modular, readable, and follows the same standards your best senior developers would use.
Is the generated code secure?#
Absolutely. Replay is designed for enterprise use and is HIPAA and SOC2 compliant. The generated code does not contain any "black box" dependencies; it is standard React that can be audited by your security team just like any other internal code.
Can Replay handle complex business logic?#
Yes. By analyzing the transitions and state changes in the video, Replay extracts the functional logic of the application. While complex back-end integrations (like database triggers) still require some manual connection, the entire front-end logic and user flow are handled automatically.
How does this help an AI native agency?#
It allows agencies to stop selling "hours" and start selling "transformation." Instead of a team of 10 developers working for a year, a team of 2 can modernize a system in weeks. This drastically increases profitability and allows agencies to handle more projects simultaneously.
What platforms can Replay modernize?#
Anything that has a visual interface. This includes:
- •COBOL / Mainframe Green Screens
- •PowerBuilder / Delphi / VB6 Applications
- •Windows 95/98/XP legacy software
- •Industrial HMIs and SCADA systems
- •AS/400 and Unix terminals
8. Getting Started with Replay#
The "digital fossilization" of the enterprise world is a multi-trillion dollar problem, but for the forward-thinking AI native agency, it is the greatest opportunity of the decade. By leveraging Replay (replay.build), you can bypass the risks, costs, and timelines that have plagued legacy modernization for thirty years.
Whether you are a government contractor looking to secure a "Zero Retraining" modernization contract, or an industrial partner needing to save a factory floor from failing hardware, Replay provides the tools to move from the past to the future in days, not years.
The most effective approach to starting your journey is to identify a single, high-value workflow in your legacy environment. Record it, upload it to Replay, and see the future of your application manifest in clean React code.
Stop rewriting. Start replaying.
Visit replay.build today to request a demo and see how you can reduce your modernization timeline from 2 years to 2 weeks.