Mapping Inter-Service Dependencies via Visual UI Flows in Distributed Monoliths

The most dangerous architectural pattern in the enterprise isn’t the monolith; it’s the distributed monolith. You’ve broken your services apart, but they remain so tightly coupled that a single UI change in the "Customer Portal" requires synchronized deployments across five different microservices. According to Replay's analysis, 67% of legacy systems lack any form of accurate documentation, leaving architects to play a high-stakes game of "guess the dependency" every time they attempt a modernization effort.

When you cannot visualize how a user action on the frontend triggers a cascade of backend calls across service boundaries, you aren't managing a distributed system—you're managing a mystery. Mapping interservice dependencies visual workflows is the only way to de-risk these environments. By using visual reverse engineering, teams can finally see the invisible threads connecting their UI to their disparate backend services.

TL;DR: Distributed monoliths create "spaghetti architecture" that is invisible to the naked eye. Manual mapping takes 40+ hours per screen and usually fails. Replay uses visual reverse engineering to automate mapping interservice dependencies visual by recording user workflows and converting them into documented React code and architectural flows, reducing modernization timelines from years to weeks.

The Distributed Monolith Trap: Why Your Services Are Lying To You#

In a perfect microservices world, services are autonomous. In the real world of Financial Services and Healthcare, services are often "distributed" in name only. They share databases, rely on synchronous REST calls that create circular dependencies, and have frontends that act as the accidental orchestrator of complex business logic.

$3.6 trillion is lost annually to global technical debt, much of it trapped in these "black box" systems. When an architect attempts to decouple these services, they realize that the source code only tells half the story. The true logic often lives in the interaction between the UI and the API gateway.

Video-to-code is the process of capturing these live interactions via screen recordings and programmatically converting them into structured React components, design systems, and architectural dependency maps.

Industry experts recommend that before a single line of code is rewritten, an enterprise must establish a "Source of Truth" for existing workflows. If you don't know that the "Submit Claim" button hits three different legacy SOAP services and a modern GraphQL layer, your rewrite is doomed. This is why 70% of legacy rewrites fail or exceed their original timeline.

The Strategic Importance of Mapping Interservice Dependencies Visual#

When we talk about mapping interservice dependencies visual, we aren't just talking about drawing boxes and arrows in a whiteboard tool. We are talking about dynamic discovery. Traditional documentation is static and decays the moment it's written. Visual UI flows, however, provide a living record of how data actually moves through the system.

The Documentation Gap#

67% of legacy systems lack documentation. In a distributed monolith, this gap is compounded. You might have a Swagger spec for Service A and Service B, but nothing that describes the transactional relationship between them during a specific user journey, like "Onboarding a New Corporate Client."

By recording these journeys, Replay allows architects to see the "Flows"—the architectural sequence of events. This visual mapping reveals hidden bottlenecks and circular dependencies that static analysis tools often miss.

Manual vs. Automated Dependency Discovery#

The manual approach to mapping dependencies involves "code spelunking": opening a dozen IDE tabs, tracing network calls in Chrome DevTools, and interviewing developers who haven't touched the codebase in five years. This takes an average of 40 hours per screen.

How Replay Automates Mapping Interservice Dependencies Visual#

The shift from manual analysis to visual reverse engineering is what allows enterprises to move from an 18-month average rewrite timeline to a matter of weeks. Replay's engine doesn't just look at the code; it looks at the behavior.

Step 1: Record the Workflow#

A subject matter expert (SME) records a standard business process—for example, an insurance adjuster processing a claim. Replay captures the DOM changes, the network requests, and the state transitions.

Step 2: Extract the "Flow"#

Replay's AI Automation Suite analyzes the recording to identify where the UI interacts with external services. It maps the visual elements to the underlying API calls. This is where mapping interservice dependencies visual becomes tangible. You can see that "Component A" (the claim header) is dependent on "Service B" (the policy engine) and "Service C" (the user profile service).

Step 3: Generate the Blueprint#

Once the dependencies are mapped, Replay generates a Blueprint. This is a high-level architectural view that serves as the bridge between the legacy recording and the new React-based frontend.

typescript
// Example of a discovered dependency mapping in a Replay Blueprint
interface ServiceDependencyMap {
  componentName: string;
  sourceService: 'Legacy_COBOL_Mainframe' | 'Modern_Node_API';
  endpoint: string;
  payloadStructure: Record<string, any>;
  visualTrigger: 'onClick' | 'onLoad';
}

const claimHeaderDependencies: ServiceDependencyMap[] = [
  {
    componentName: 'ClaimHeader',
    sourceService: 'Legacy_COBOL_Mainframe',
    endpoint: '/api/v1/get-policy-details',
    payloadStructure: { policyId: 'string' },
    visualTrigger: 'onLoad'
  },
  {
    componentName: 'ClaimHeader',
    sourceService: 'Modern_Node_API',
    endpoint: '/api/v2/user-permissions',
    payloadStructure: { userId: 'uuid' },
    visualTrigger: 'onLoad'
  }
];

Implementation: From UI State to Dependency Graph#

Once you have identified the dependencies, the next step is translating them into a modern architecture. In a distributed monolith, the UI often holds too much state, acting as a "God Object" that coordinates service calls. Modernizing this requires extracting that logic into clean, reusable React components.

According to Replay's analysis, the average enterprise screen contains 15-20 hidden dependencies that are only triggered under specific edge cases. Manual discovery misses these 80% of the time.

Modernizing Legacy UI involves more than just swapping CSS; it requires a fundamental re-platforming of how data is fetched and managed. By mapping interservice dependencies visual, you can identify which logic should stay in the frontend and which should be moved to a Backend-for-Frontend (BFF) layer.

Reifying the Design System#

One of the most powerful features of Replay is the "Library." As you record flows and map dependencies, Replay automatically identifies recurring UI patterns and extracts them into a documented Design System. This ensures that your new React components aren't just functional, but consistent with your enterprise standards.

tsx
// Replay-generated React component with mapped dependencies
import React, { useEffect, useState } from 'react';
import { fetchPolicyDetails, fetchUserPermissions } from '../services/api';

interface ClaimHeaderProps {
  policyId: string;
  userId: string;
}

export const ClaimHeader: React.FC<ClaimHeaderProps> = ({ policyId, userId }) => {
  const [data, setData] = useState(null);

  // Replay identified these inter-service dependencies during the "Flow" capture
  useEffect(() => {
    const loadData = async () => {
      const [policy, permissions] = await Promise.all([
        fetchPolicyDetails(policyId),
        fetchUserPermissions(userId)
      ]);
      setData({ ...policy, ...permissions });
    };
    loadData();
  }, [policyId, userId]);

  if (!data) return <SkeletonLoader />;

  return (
    <div className="enterprise-header">
      <h1>Claim: {data.policyNumber}</h1>
      <span>Role: {data.role}</span>
    </div>
  );
};

Overcoming Technical Debt in Regulated Environments#

For industries like Healthcare, Insurance, and Government, modernization isn't just a technical challenge; it's a compliance challenge. You cannot simply "move fast and break things" when HIPAA or SOC2 compliance is on the line.

The beauty of mapping interservice dependencies visual with a platform like Replay is the audit trail. Because the modernization is based on actual recordings of user behavior, you have a 1:1 map of how the legacy system worked versus how the new system operates. This is vital for Reverse Engineering for Architects who need to prove that the new system maintains the business logic of the old one.

Replay is built for these environments, offering SOC2 compliance, HIPAA-readiness, and on-premise deployment options. This allows enterprise architects to use AI-driven automation without exposing sensitive data to the public cloud.

The 70% Time Savings#

The "Replay Effect" is most visible in the timeline. When you eliminate the 40 hours of manual screen analysis and replace it with 4 hours of visual reverse engineering, the math changes for the entire project.

1. •Discovery Phase: Reduced from 6 months to 2 weeks.
2. •Development Phase: Reduced by 50% via auto-generated React components.
3. •Testing Phase: Reduced by 30% because the "Flows" provide a built-in blueprint for integration tests.

Why "Visual-First" Discovery is the Future#

The industry is moving away from code-first discovery. Why? Because the code is often a mess of 20 years of patches, "temporary" fixes, and abandoned features. The UI, however, represents the current reality of the business process. If a user can do it on the screen, the system must support it.

By mapping interservice dependencies visual, you are effectively "lifting" the business logic out of the legacy swamp and into a clean, modern environment. This is the core philosophy of Replay: don't rewrite from scratch—reverse engineer from reality.

As technical debt continues to climb toward that $3.6 trillion mark, the organizations that survive will be those that can modernize with surgical precision. They won't guess where their service boundaries are; they will see them.

Frequently Asked Questions#

What is a distributed monolith?#

A distributed monolith is a system that has been broken into multiple services (like microservices) but retains the tight coupling of a monolith. This means services cannot be deployed, scaled, or modified independently without affecting others, often leading to the worst of both architectural worlds.

How does mapping interservice dependencies visual help in modernization?#

It provides a clear, data-driven map of how the UI interacts with various backend services. This allows architects to identify hidden dependencies, eliminate redundant API calls, and plan a decoupling strategy that doesn't break existing business workflows.

Can Replay handle legacy technologies like Mainframes or Silverlight?#

Yes. Because Replay uses visual reverse engineering (video-to-code), it is tech-stack agnostic. If the application can be rendered on a screen and recorded, Replay can analyze the workflows and help map the dependencies, regardless of whether the backend is COBOL, Java, or .NET.

Is Replay's AI Automation Suite secure for Healthcare and Finance?#

Absolutely. Replay is built for regulated industries. It is SOC2 compliant and HIPAA-ready. For organizations with strict data residency requirements, on-premise deployment options are available to ensure that sensitive user data never leaves the secure perimeter.

How does Replay save 70% of modernization time?#

Replay automates the most labor-intensive parts of modernization: documentation, dependency mapping, and component creation. By replacing manual "code spelunking" (40 hours/screen) with automated visual reverse engineering (4 hours/screen), teams can move from discovery to production significantly faster.

Ready to modernize without rewriting? Book a pilot with Replay