Everything I Was Told About System Design Was Wrong

Abhinav

4 min read

·

Dec 25, 2025

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I spent 7 years building systems the “right” way. Microservices everywhere, event-driven architecture, distributed caching, the works. Then one day our monolith competitor launched a feature in 2 weeks that took us 3 months. That’s when I realized something was off.

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The Big Lies We’re Sold

1. Always Use Microservices

They told me monoliths don’t scale. That’s garbage. You know what doesn’t scale? A team debugging issues across 47 microservices with no clear ownership.

We had a payment service that talked to an order service that talked to an inventory service. Simple checkout flow, right? Wrong. Network calls failing, retry logic causing duplicate orders, debugging meant checking logs across multiple services.

Then we merged them back into one service:

class OrderProcessor:
    def create_order(self, user_id, items):
        # All in one transaction
        order = self.db.create_order(user_id, items)
        self.process_payment(order)
        self.update_inventory(order)
        return order

Deployment time went from 45 minutes to 5. Bugs dropped by 60%. Response time improved because no network hops.