# Cars24 Improves Search For 300 Million Users With MongoDB Atlas

[MongoDB](https://yomu.fyi/company/mongodb) · Nick Bell · Oct 12, 2025

**Type:** Problem & solution

## Summary

Online car marketplace Cars24 previously operated a dual architecture where relational databases like Postgres synchronized data into separate search engines like Elasticsearch. As service offerings expanded globally for 300 million users, multiple engineering teams piping data into a single search index caused severe synchronization challenges, operational overhead, and developer friction. To simplify this infrastructure, Cars24 migrated to MongoDB Atlas hosted on Google Cloud, utilizing integrated Apache Lucene-powered MongoDB Atlas Search directly within the database layer. This architectural shift eliminated synchronization pipelines while accelerating search feature delivery through a unified API. Cars24 also replaced its ArangoDB geospatial search deployment with MongoDB Atlas, achieving robust multi-document ACID transactions across shards and cutting operational costs by 50%.

## Context

Cars24 faced synchronization challenges, heavy operational overhead, and decreased developer productivity while syncing data from databases like Postgres to external search engines like Elasticsearch. Additionally, its geospatial search setup on ArangoDB suffered from performance bottlenecks, weak transaction guarantees, and limited ecosystem support.

## Approach / What changed

Cars24 adopted MongoDB Atlas hosted on Google Cloud to integrate operational data storage and Apache Lucene-powered search within a single platform. It later replaced ArangoDB with MongoDB Atlas to consolidate geospatial search workloads and leverage multi-document ACID transactions across shards.

## Takeaways

- Running embedded MongoDB Atlas Search powered by Apache Lucene eliminated the need for external data synchronization pipelines and separate indexing infrastructure.
- Migrating geospatial search workloads from ArangoDB to MongoDB Atlas delivered 50% cost savings alongside multi-document ACID transactions across shards.
- Consolidating database and search operations under a unified API reduced operational overhead and simplified developer onboarding across growing engineering teams.

**Tags:** [Architecture](https://yomu.fyi/topic/architecture), [Google Cloud](https://yomu.fyi/topic/gcp), [Migrations](https://yomu.fyi/topic/migration), [Scalability](https://yomu.fyi/topic/scalability), [Search](https://yomu.fyi/topic/search)

[Read original post](https://www.mongodb.com/company/blog/innovation/cars24-improves-search-for-300-million-users-with-atlas)