TreeHouse powers two of the largest real estate marketplaces in the Netherlands: huurwoningen.nl and pararius.nl. Both sites host over 2 million unique monthly visitors. Treehouse is maintained by a team of 40 developers and since 2013, Symfony has become the backbone of both their B2C marketplaces and B2B agent tools, supporting massive product growth and technical complexity.
The high-volume open house: Broadcasting 1 million alerts daily with Symfony
TreeHouse’s alert engine dispatches over 1 million emails each day, notifying users about new listings matching their criteria. To scale this massive workload across their Dutch (pararius.nl and huurwoningen.nl), UK (rentaroof.co.uk), and French (toitpourtoi.fr) platforms, the team leverages a powerful stack combining Symfony, Elasticsearch, Google Pub/Sub, and SendGrid. The native compatibility of Symfony with modern cloud infrastructure and its rich ecosystem of bundles have been crucial in keeping the codebase clean and manageable.
The next major milestone for TreeHouse is enhancing the search experience through AI agents. These agents will guide home seekers in fine-tuning their search queries to maximize their chances of finding a home. The emerging Symfony AI tools are proving to be a massive asset in getting this innovative system up and running quickly.
The hourly property inspection: 300k listings every 60 minutes
Every single hour, TreeHouse audits around 300,000 real estate listings via their Casco platform. This continuous inspection ensures that data from external CRMs is perfectly synced. Built as a collection of long-running console applications, the system relies heavily on Symfony Console and HTTP Client.
Backed by a Google Pub/Sub messaging spine and a robust Kubernetes infrastructure, the system scales automatically as the volume of listings fluctuates. Symfony shines in this environment, offering native support for signal handling and structured error logging, which are essential for stable containerized operations.
Thanks to this cloud infrastructure and deep expertise in PHP and Symfony, TreeHouse handles these massive processing loads without needing to introduce languages like Python. By breaking heavy tasks into small, isolated chunks, they achieve highly efficient scaling using Kubernetes and Pub/Sub.
A continuous renovation
The Casco application originally started on Symfony 4 and has been systematically upgraded with every single release. Today, the platform always runs on the latest stable versions of PHP and Symfony. TreeHouse enforces a strict upgrade policy for every minor and major release.
Rebuilding the CRM brick by brick
Beyond marketplaces, TreeHouse develops specialized B2B products to help real estate agents find the perfect tenants. Their flagship CRM, Pararius Office, allows agents to manage portfolios and publish listings across multiple marketplaces.
Originally built on the legacy Zend Framework, the CRM is currently being completely migrated to Symfony. To achieve this without interrupting service, the team is using the Strangler Fig Pattern, gradually replacing old controllers with Symfony ones. A proxyservice sits in front of both PHP applications, intelligently routing traffic while ensuring a completely seamless, unified login session for users across both systems.
Managing the rental rush: Simplifying thousands of viewing requests
In high-demand cities like Amsterdam, a new listing triggers hundreds of viewing requests in just a few hours. To prevent inbox chaos, TreeHouse built a workflow tool that automates candidate screening, schedules viewings, and verifies IDs. Architectured as a React Single Page Application (SPA) with a Symfony backend, the application delivers a fast experience, leveraging Symfony’s ability to build robust JSON API endpoints with the same ease as traditional HTML.
Ultimately, Symfony has proven to be much more than just a framework for TreeHouse, it is the solid foundation that keeps their digital estate scaling smoothly. From handling millions of daily alerts to remodeling legacy CRMs brick by brick, this robust ecosystem empowers their team to innovate with total confidence. As they look toward the future with AI integration, TreeHouse’s team can rely on an architecture that is fully equipped to continue leading the way in European PropTech.
Thanks to Johnny van de Laar, Engineering manager (Aanbod, DevOps, Pararius Office)
Technical stack
- Symfony
- React
- Kubernetes
- Google Pub/Sub
- SendGrid
- Elasticsearch