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February 11, 20268 min readdeath discovery phase

The Death of the Discovery Phase: Why Video is Faster than Manual Audits

R
Replay Team
Developer Advocates

The $3.6 trillion global technical debt crisis isn't a coding problem—it’s a discovery problem. Most enterprise modernization projects die in a boardroom months before a single line of code is written, suffocated by a "Discovery Phase" that functions more like an archaeological dig than an engineering sprint.

When 67% of legacy systems lack any meaningful documentation, and the original architects have long since departed, the standard industry response is to spend six months and hundreds of thousands of dollars on manual audits. This is a systemic failure. We are asking senior engineers to play detective, guessing at business logic hidden behind decades of "spaghetti" code and undocumented edge cases.

The death of the discovery phase is here. We are moving from manual archaeology to automated extraction. By using video as the source of truth, we can bypass the 18-month "Big Bang" rewrite cycle and move directly to a documented, modern codebase in days.

TL;DR: Manual discovery phases are the primary cause of the 70% failure rate in legacy rewrites; Replay replaces months of auditing with visual reverse engineering, reducing screen-to-code time from 40 hours to just 4.

The Archaeology Tax: Why Manual Audits Fail#

In a typical Financial Services or Healthcare environment, the legacy system is a black box. The "Discovery Phase" usually involves interviewing stakeholders who don't remember the logic, reading stale Jira tickets, and attempting to map out dependencies manually.

This process is fundamentally flawed because it relies on human memory and incomplete documentation. It leads to the "Iceberg Effect": you plan for the 10% of the logic you can see, only to be sunk by the 90% of undocumented business rules hidden in the legacy state.

ApproachDiscovery TimelineImplementation RiskAverage CostDocumentation Quality
Big Bang Rewrite6-9 MonthsHigh (70% fail)$$$$Poor/Incomplete
Strangler Fig3-6 MonthsMedium$$$Moderate
Replay Extraction1-2 WeeksLow$High (Generated)

The "Big Bang" approach fails because the target is always moving. By the time you finish the 18-month rewrite, the business requirements have evolved, and you've built a modern version of an obsolete system.

Visual Reverse Engineering: Video as Source of Truth#

The future of modernization isn't rewriting from scratch—it's understanding what you already have. Visual Reverse Engineering works by recording real user workflows. Instead of reading code to understand behavior, we observe behavior to generate code.

Replay records the interaction, captures the DOM state, maps the API calls, and extracts the underlying business logic. This transforms the legacy system from a black box into a documented React component library.

From Legacy Mess to Clean React#

Consider a legacy insurance claims form. Manually migrating this requires identifying every validation rule, every conditional field, and every API endpoint. With Replay, the recording captures these interactions in real-time.

typescript
// Example: Generated React Component from Replay Extraction // Source: Legacy Claims Portal (v4.2) // Logic: Preserved via Visual Reverse Engineering import React, { useState, useEffect } from 'react'; import { Button, Input, Alert } from '@/components/ui'; // From Replay Library import { validatePolicyFormat, submitClaimData } from '@/api/claims-proxy'; export const MigratedClaimsForm = ({ userRole, policyId }: ClaimsProps) => { const [formData, setFormData] = useState<ClaimState>(null); const [error, setError] = useState<string | null>(null); // Replay extracted this conditional logic from the legacy workflow: // If policy is 'Type-B', the 'Deductible' field must be pre-populated. useEffect(() => { if (policyId.startsWith('B-')) { fetchLegacyDeductible(policyId).then(val => setFormData(prev => ({ ...prev, deductible: val })) ); } }, [policyId]); const handleSubmit = async (e: React.FormEvent) => { e.preventDefault(); try { // Replay generated the API contract based on recorded XHR traffic await submitClaimData(formData); } catch (err) { setError("Legacy System Validation Failed: " + err.message); } }; return ( <form onSubmit={handleSubmit} className="p-6 space-y-4"> <Input label="Policy Number" value={policyId} disabled /> {/* Dynamic fields extracted from recorded user flows */} <Button type="submit">Sync to Modern Core</Button> </form> ); };

💡 Pro Tip: Don't try to refactor business logic during the extraction phase. Use Replay to get to a "functional parity" state first. Once you have a documented React component, refactoring becomes a low-risk task rather than a guessing game.

The 3-Step Death of the Discovery Phase#

We are replacing the 18-month rewrite timeline with a high-velocity extraction pipeline. Here is how Enterprise Architects are using Replay to bypass the discovery trap.

Step 1: Workflow Recording (The Assessment)#

Instead of a 50-page requirements document, subject matter experts (SMEs) record themselves performing core business tasks in the legacy system. Replay captures the technical "ground truth"—the exact API payloads, state changes, and UI transitions.

Step 2: Automated Extraction (The Blueprint)#

The AI Automation Suite analyzes the recording. It generates:

  • API Contracts: Swagger/OpenAPI specs based on actual legacy traffic.
  • E2E Tests: Playwright or Cypress scripts that mirror the user's actions.
  • Technical Debt Audit: A visual map of where the legacy system's logic is most convoluted.

Step 3: Component Generation (The Library)#

Replay extracts the UI into modern React components. These aren't just "scraped" visuals; they are functional components mapped to your organization’s Design System. What used to take 40 hours per screen of manual development now takes 4 hours.

💰 ROI Insight: For a typical enterprise application with 100 screens, Replay saves approximately 3,600 engineering hours. At a blended rate of $150/hr, that is a direct cost saving of $540,000 per application, not including the value of a faster time-to-market.

Documentation Without Archaeology#

The most significant pain point in legacy systems isn't the old code—it's the missing context. Replay provides "Flows" (Architecture mapping) and "Blueprints" (Editor) that serve as a living document.

When a new developer joins the team, they don't have to spend weeks learning a proprietary 20-year-old framework. They can watch the Replay recording, see the generated React code, and understand the API contract immediately.

⚠️ Warning: Be wary of "AI Rewriters" that claim to convert COBOL or Java to React without a visual source of truth. Without recording the actual user interaction, these tools often miss the "hidden" state changes that occur in the browser or the complex conditional rendering that defines the user experience.

Security and Compliance in Regulated Industries#

For Financial Services and Healthcare, "moving fast" cannot come at the cost of security. Manual discovery often involves exporting sensitive data to spreadsheets or external consultants.

Replay is built for SOC2 and HIPAA-ready environments.

  • On-Premise Availability: Keep your legacy data and the extraction process within your firewall.
  • PII Masking: Automatically redact sensitive data during the recording and extraction phase.
  • Audit Trails: Every generated component is linked back to the original recording, providing a clear chain of custody for business logic.
FeatureManual AuditReplay Platform
PII HandlingManual/RiskyAutomated Masking
DeploymentN/A (Documents)On-Prem / VPC
Audit TrailNoneRecording-to-Code Link
ComplianceHard to VerifySOC2 / HIPAA Ready

The End of the "Black Box"#

The goal of modernization is to eliminate the "black box" that holds your business hostage. When you can't update a feature because no one knows how the original code works, you aren't just dealing with technical debt; you're dealing with business paralysis.

By killing the discovery phase and moving to visual reverse engineering, you regain control. You stop being an archaeologist and start being an architect again.

typescript
// Example: Replay-generated API Contract (Swagger/OpenAPI) // This replaces weeks of manual network analysis. /** * @openapi * /api/v1/legacy/process-transaction: * post: * summary: Extracted from Legacy Payment Workflow * description: Handles multi-stage verification for cross-border transfers. * requestBody: * content: * application/json: * schema: * type: object * properties: * tx_id: {type: string} * auth_token: {type: string} * retry_count: {type: integer} */

Frequently Asked Questions#

How long does legacy extraction actually take?#

While a manual discovery phase for a complex module can take 3-6 months, Replay typically completes the extraction of core workflows into documented React components in 2-8 weeks. The recording itself happens in real-time; the AI-assisted generation and cleanup happen shortly after.

What about business logic preservation?#

This is the core strength of Replay. Because we use "Video as the Source of Truth," we capture the outcome of the business logic. If a legacy system calculates a specific tax rate based on five hidden variables, Replay captures the inputs and the resulting state, allowing developers to replicate or bridge that logic with 100% accuracy.

Does this replace my developers?#

No. Replay replaces the "grunt work" of discovery and boilerplate generation. It frees your senior architects to focus on the high-level system design and the integration of the new modern components into your existing ecosystem. It turns your developers from "code hunters" into "system builders."

Can it handle mainframe or green-screen systems?#

Yes. If a user can interact with it through a browser or a terminal emulator, Replay can record the workflow and extract the logic. We have successfully helped organizations bridge the gap from 30-year-old mainframe interfaces to modern web architectures.


Ready to modernize without rewriting? Book a pilot with Replay - see your legacy screen extracted live during the call.

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