Skip to main content
2025-08-2612 min read
System Architecture

AI and the Final Nail in the Coffin of Microservices: All Hail the Monorepo and Monolith

The Revenge of the Boring Architecture

The pendulum of software architecture has swung decisively. After a decade of breaking everything into tiny, supposedly manageable pieces, we're witnessing the great reconvergence. AI hasn't just changed how we write code—it's fundamentally altered the economics and practicalities of how we organize it.

The Microservices Promise That AI Broke

Remember when microservices were going to save us all? Small, focused services. Independent deployments. Technology diversity. Teams moving at their own pace. It was a beautiful dream, until we woke up to the nightmare of distributed system complexity, service mesh hell, and the realization that we'd traded one set of problems for a far more insidious set.
But here's the thing: it never made sense. We fell for a collective delusion that breaking apart perfectly functional applications would somehow make them better. We replaced function calls with network calls. We replaced stack traces with distributed tracing. We replaced deployment with orchestration nightmares.
Now AI has entered the chat, and it's exposing just how unnecessary this complexity always was.

Monolith Simplicity

User Request

Monolith

Database

Message Queue

Microservices Reality

Network Call

Network Call

Network Call

Network Call

User Request

API Gateway

Auth Service

User Service

User DB

Order Service

Order DB

Payment Service

Payment DB

Notification Service

Message Queue

Why AI Loves Monoliths

1. Context is King

Modern AI coding assistants thrive on context. They need to understand your entire system, not just fragments scattered across 47 different repositories. In a monolith, an AI can trace a request from the API endpoint through the business logic to the database query in seconds. In a microservices architecture? Good luck teaching it to navigate your service discovery, API gateways, and the seventeen different authentication mechanisms you've accidentally implemented.

2. The Refactoring Revolution

AI makes large-scale refactoring not just possible, but trivial. That terrifying 10,000-line service that no one wanted to touch? AI will refactor it while you grab coffee. The argument for microservices as a way to limit blast radius becomes moot when AI can safely transform vast codebases with inhuman precision.

3. The Death of Conway's Law

Conway's Law states that organizations design systems that mirror their communication structures. Microservices were, in many ways, an admission of organizational failure—we couldn't get teams to communicate, so we built architectures that didn't require it.
AI doesn't care about your org chart. It can maintain cognitive coherence across a massive codebase that would break a human team. The artificial boundaries we created for human limitations are now just obstacles.

The Monorepo Renaissance

GitHub Copilot, Cursor, and other AI tools perform exponentially better when they can see your entire codebase. The monorepo isn't just convenient—it's becoming essential for AI-assisted development.

Monorepo Paradise

Full Context

✅ Full visibility

✅ Full visibility

✅ Full visibility

✅ Full visibility

AI Assistant

Monorepo

User Module

Order Module

Payment Module

Auth Module

Multi-Repo Nightmare

Limited Context

Limited Context

Limited Context

Limited Context

❌ Can't see

❌ Can't see

❌ Can't see

AI Assistant

User Service Repo

Order Service Repo

Payment Service Repo

Auth Service Repo

Consider these advantages in the AI age:
  • Instant cross-project refactoring: Change an interface, and AI updates every consumer across your entire system
  • Holistic optimization: AI can identify duplicate code and redundant patterns across what would have been separate services
  • Simplified mental model: One repository, one set of tools, one deployment pipeline—AI can master it all

The New Economics of Complexity

The dirty secret of microservices was always the operational overhead. We traded development complexity for operational complexity, then convinced ourselves that Kubernetes would save us. It didn't.
AI changes the calculus entirely:

Monolith Operations

Monolith

Load Balancer

Database

App Logs

1-2 Engineers

Microservices Operational Overhead

Microservices

Kubernetes

Service Mesh

Service Discovery

Distributed Tracing

Centralized Logging

Config Management

API Gateway

Circuit Breakers

Message Queues

DevOps Team

Observability Team

Platform Team

  • Development complexity: Now manageable at scales previously unthinkable
  • Operational complexity: Still a nightmare in distributed systems
  • Debugging: AI can trace through a monolith's call stack in milliseconds; distributed tracing across services remains painful
  • Testing: AI can generate comprehensive test suites for monoliths; testing microservice interactions remains combinatorially explosive

The Performance Paradox

Here's the kicker: monoliths are often faster. No network hops. No serialization overhead. No service mesh latency. And with AI helping optimize hot paths and identify bottlenecks, the performance gap is only widening.
The microservices tax (all those network calls, all that serialization, all those distributed transactions) was justified when human cognitive limits demanded smaller, isolated codebases. AI has no such limits.

But What About Scale?

"But monoliths don't scale!" the microservices faithful used to cry. Notice the past tense? They've gone awfully quiet lately.
The silence from the microservices camp is deafening. Where are the conference talks now? Where are the Medium posts about how their 400-service architecture is working out? They're too busy trying to debug distributed transactions and figure out why their observability bill is higher than their AWS compute costs.
Here's the thing the microservices evangelists never understood: horizontal scaling works perfectly fine with monoliths. Spin up more instances, put them behind a load balancer, and let it handle resource allocation. Why manually decide that the "user service" needs 5 instances while the "order service" needs 3? Just run 8 instances of your monolith and let the load balancer do what it does best—balance load.
The entire premise of "scale services independently" was solving a problem that didn't exist. Your load balancer already knows how to distribute traffic. Your auto-scaling already knows when to add instances. Breaking your app into pieces just made everything harder.
AI makes this approach even more viable. It can identify bottlenecks, suggest caching strategies, and optimize database queries at a scale no human team could match.

The Great Reconvergence

We're not going back to the monoliths of 2005. We're moving forward to AI-native architectures that happen to look remarkably monolithic:

The Architecture Evolution

Scaling Pain

Complexity Hell

AI Revolution

Features

Features

Features

Features

2000s: Monolith

2010s: Microservices

2015s: Distributed Monolith

2025s: AI-Native Monolith

Simple
Debuggable
Fast

Complex
Distributed
Slow

Worst of Both
Worlds

Simple
AI-Powered
Scalable

  • Modular monoliths: Clear boundaries without network calls
  • Monorepos: All code visible to AI, with tooling to manage scale
  • Edge computing: Push only what's necessary to the edge, keep core logic centralized
  • AI-first development: Architecture decisions driven by what makes AI most effective

The Path Forward

The transition won't happen overnight. Organizations with significant microservices investments will struggle with sunk cost fallacy. But the writing is on the wall—or rather, in the AI-generated code.
Start small:
  1. Stop creating new microservices
  2. Begin consolidating related services
  3. Invest in monorepo tooling
  4. Train your AI tools on your entire codebase
  5. Let AI guide the reconvergence

Conclusion: Embrace the Monolith

The microservices era was never necessary—it was a costly mistake driven by resume-driven development and conference-driven architecture. We didn't learn valuable lessons; we learned expensive ones about making simple things complicated.
The future is not distributed—it's consolidated, AI-optimized, and surprisingly monolithic. The teams that recognize this shift early will have a significant advantage. The rest will be maintaining their service meshes and wondering why their AI tools keep generating boilerplate for inter-service communication.
All hail the monorepo. All hail the monolith. The AI has spoken.
⚠️
Note: This post is intentionally provocative. The reality is that different architectures suit different needs, and microservices still have their place. But the AI revolution is definitely shifting the balance back toward consolidated codebases and simplified architectures. The pendulum swings, and right now, it's swinging hard toward simplicity.

Part of

The Microservices Delusion

Part 2 of 2