Real-Time Recommender System for Fashion E-commerce

A real-time product recommender for an e-commerce catalogue — content-based and collaborative signals combined — serving personalised suggestions in under 10ms per request.

Real-Time Recommender System for Fashion E-commerce

01. Challenge

The existing storefront showed the same "popular items" to everyone. Personalisation products on the market either required sending full user data to a third party, or introduced latency that hurt page-load metrics.

The team needed a recommender they controlled, fast enough to render inline, and good enough to lift conversion without spamming users with items they had already bought.

02. Solution

A hybrid recommender combining content-based features (product attributes, images, embeddings) with collaborative signals (co-views, co-purchases, session sequences).

Models are retrained on a daily cadence, served behind a thin Go API at single-digit millisecond latency, with feature flags so the team can A/B test ranking strategies.

03. Results

  • < 10 msLatency
    Per-request recommendation serving
  • Real-timePersonalisation
    Recommendations reflect current session activity
  • HandledCold start
    Content-based fallback for new products and users

04. Constraints

  • Real-time inference budget: < 10 ms per recommendation request
  • Catalogue and user signals change continuously — model must update without downtime
  • Cold start: new products and new users must get sensible recommendations from day one
  • Multi-region traffic — recommender must be deployed close to users

05. Architecture

A feature pipeline aggregates product attributes and behavioural signals (views, add-to-carts, purchases) into an offline feature store.

Candidate generation combines ANN search over product embeddings with collaborative-filtering signals; a lightweight ranking model scores candidates per request.

A Go service serves recommendations behind a CDN, with feature flags and online metrics for ranking experiments.

06. Tech Stack

PythonGoPyTorchLightFMXGBoostFaissQdrantRedisBigQueryKafkaKubernetes

Project Info

  • Client Fashion e-commerce retailer (EU)
  • Service AI Integrations
  • Timeline 12 weeks
  • Industryecommerce