100,000+ listings, filtered live, without a plugin in sight.

Context

OLX’s advertising team needed a marketplace for [[TODO: WHAT: e.g. dealer stock / partner inventory]] that lived alongside the main platform but couldn’t depend on its release cycle. Listings came from [[TODO: SOURCE: external feeds / partner systems]], in different formats, refreshed [[TODO: daily / hourly]]. The catalogue had to be browsable by category-specific attributes, fast, on mobile, under campaign traffic.

The existing setup was [[TODO: WHAT WAS THERE BEFORE, one sentence]] and couldn’t be replaced overnight.

The challenge

The hard part was not the visual design. It was data and logic.

• Thousands of listings from OLX.ro sources, each with its own field names and quality problems, normalised into one model.
• Filters that change by category: a car has mileage and fuel, an apartment has rooms and floor. Interdependent, not a flat list.
• Imports that must not degrade the site while running.
• A generic CMS pattern with plugins would have broken at this scale.

Approach

What I built

Data first. Custom database structures for listings, sellers, categories, attributes and values, treated as first-class entities rather than post meta. The data model was agreed with the product team before a single screen was designed.

Ingestion separated from browsing. A controlled import pipeline validates, normalises and stages incoming data, then swaps it in. Public queries never touch the import tables.

Filters as configuration. Attributes and their dependencies live in the admin. Adding a new category or attribute is a configuration task, not a development task.

UI designed on the real data. The interface was built in Figma against the actual attribute sets, so no design promised a filter the data couldn’t deliver. Reusable components covered romanian markets.

Performance by structure. Indexed queries, predictable execution plans, cached filter counts.

Result

• 100,000+ listings served with category-specific filtering, [[TODO: X ms]] on mobile.
• New attributes and categories added without a developer since [[TODO: YEAR]].
• Imports of [[TODO: N]] listings run [[TODO: daily / hourly]] with no measurable impact on browsing.
• The platform has been extended [[TODO: N]] times since launch ([[TODO: examples: new markets, new partner feeds, new sections]]) without a rewrite.
• [[TODO: TRAFFIC OR BUSINESS RESULT IF PUBLISHABLE: e.g. “X leads per month to partners”, “Y% of OLX partner inventory browsed here”]]

How I worked with the team

Direct technical partnership with the advertising and product team: architecture decisions, UI decisions and code by the same person. Weekly iterations and staging for every change. There were no handoffs between designer, front-end and back-end developer, because all three were me.

This is one of 100+ projects delivered for OLX Group since 2018.