Yolcu360 is the largest online car rental platform in Turkey. At its inception, the system was a traditional Django monolith—typical for early-stage startups. When I stepped into the CTO role, we were facing performance bottlenecks and instability during traffic surges. For example an ad campaign with discounts in a popular tv show would degrade system performance and waste marketing budget.

This is not a unique story. Many startups build MVPs quickly, and those temporary decisions become permanent as the business scales. Over time, technical debt compounds, and the monolith becomes a liability. You often hear “just a refactor will fix it,” but in reality, few systems can sustain that illusion.

Microservices aren’t a silver bullet. They introduce complexity and require discipline. But if your product is growing and the pace of change matters, staying monolithic means you’re eventually paying a tax on every new feature.

Why Microservices Were Faster for Us

Not every microservice outperforms its monolithic counterpart—but breaking free from monolithic constraints opens up new avenues for scaling. We chose Go over Python for our concurrency-heavy services. That change alone allowed us to efficiently parallelize supplier requests. Introducing a centralized caching layer further reduced latency for high-volume lookups.

More importantly, services became “first-class citizens” in our Kubernetes environment. We could deploy, scale, and recover services independently—critical when traffic spikes were unpredictable and needed instant elasticity.

The Result

After completing the migration:

  • Throughput increased 20x, enabling us to handle surges without degradation.
  • Latency dropped significantly in key user flows, as shown in the chart.
  • Integration time decreased, thanks to a new provider-mapping toolchain.
  • Team velocity improved, as smaller, isolated services made onboarding and iteration faster.

This wasn’t just a technical rewrite. It was a foundational shift that aligned our platform with the future of on-demand mobility infrastructure.