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Refactoring at Scale: Migrating Listings from a Legacy PHP Monolith
How we moved the ad lifecycle out of a decade-old PHP service and into a Java service of its own, with zero downtime and without asking any dependent system to change on the same day. Legacy: Core Monolith (PHP) · New: Listing Service (Java) · Approach: strangler fig + weighted…
Categories : Backend
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Building VAYA AI : From Filters to Conversations
Open the OLX app and you’ll find everything a buyer or seller could need: categories, filters, search, packages, and help. But a feature only helps if people can find it and know how to use it. Most users don’t think in categories and filters. They think in sentences, in English,…
Categories : Backend
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From IntelliOps to AWS DevOps Agent: How We Automated Incident RCA at OLX India
The problem: scale, noise, and 3 AM alerts Running a classifieds marketplace at OLX India’s scale means roughly 150 microservices, tens of billions of log lines flowing through a centralized ClickHouse cluster, and a user base spanning the country. Ad listings, buyer-seller chat, payments, content moderation, search, and notifications are…
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How We Reduced Backend Load Using Retrofit and OkHttp Caching in Android
Introduction Mobile applications frequently fetch the same resources—home feeds, category lists, configuration data, and other semi-static content. Repeated requests increase latency, consume bandwidth, and place unnecessary load on backend services. Retrofit relies on OkHttp for networking, and OkHttp provides built-in disk caching. However, responses are cached only when the server…
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Rebuilding One of the Most-Visited Screens in Our App: A Component-Driven Compose + MVI Architecture
Learn how OLX rebuilt its Ad Detail Page — visited 17 million times a month — using Jetpack Compose, MVI architecture, and component-driven design. Discover how they achieved a 99%+ crash-free rate by isolating failures, keeping the ViewModel lean with 46 single-responsibility handlers, and making every action run off the…