Case Study

Visual Search on

Willhaben E-commerce
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Willhaben is Austria's largest free online marketplace, with more than 10 million currently listed items. Each day, approximately 400,000 ads are posted on the platform. The marketplace covers a diverse array of categories, including real estate, automobiles and motorcycles, job listings, and a miscellaneous section aptly named \"Marketplace.\"

Notably, the fashion category, which includes clothing, shoes, and accessories, stands as one of the largest segments within the miscellaneous categories. The Willhaben website ranks among Austria's most visited websites, attracting over 8 million unique users on a monthly basis.


With our Visual Search solution, we helped Willhaben, Austria's largest online marketplace, boost user experience & engagement. Our solution allowed their users to find items effortlessly by using their phone camera as a search tool, enhancing the overall product search & discovery process.

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Visual Search is the system that uses an image taken by the user and uses that image to search for similar items from Willhaben's active listings. Users can provide an image by taking a photo with their mobile phone, taking a screenshot on their phone, or taking a photo from a catalog.

Once the photo is uploaded and processed, the system will show a list of the most visually similar items (sorted by similarity) that can be additionally filtered by attributes such as location, price, etc.


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The primary challenge of this project was to develop an ML algorithm capable of handling an immense volume of image-based searches. The final product needed to support millions of daily searches on Willhaben, one of Austria's most visited websites

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Human Similarity Judgement

The ML-based system was required to provide item recommendations based on human similarity (factors that people find similar) rather than just color, pattern, and pixel values

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First, a large classification neural network on Willhaben data is trained. Then, this network is used as a backbone for creating a system that converts an image to a numerical vector. These vectors are created so that semantically similar images are converted into similar vectors. Vectors are compared using hamming distance to enable fast comparison.

ElasticSearch is used as a search engine. All ads are put there with their vectors. Regular Elasticsearch filters can be then used to filter for price, location, category, etc., while vector similarity is used to sort the resulting items by visual similarity.

Tools and Technologies

Python Python
PyTorch PyTorch
Elasticsearch Elasticsearch
Falcon Falcon
Numpy Numpy
Triton Inference Server Triton Inference Server
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This system allows users to search the marketplace in a new and efficient way, making it easier to find the items they want. It is particularly helpful for fashion, antiques, and furniture categories where describing the style and appearance can be challenging.

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