Pinterest System Design Questions

Design a Typeahead Suggestion System

Design a search autocomplete (typeahead) service: as a user types a prefix, return the top ~10 suggestions in under 100 ms per keystroke. Suggestions are ranked by popularity and freshness (trending queries), possibly…

Also reported as: Design a Low-Latency Typeahead Service · Design autocomplete and merchant bulk edits

Design Comment Notifications with Viral-Pin Aggregation

Design a multi-channel notification service (push, email, SMS, in-app) that other services call to notify users. It must accept sudden bursts of millions of notifications with low acknowledgement latency, persist them durably,…

Also reported as: Design a Multi-Channel Notification System

Design a Distributed Rate-Limiting Service

Design a distributed rate limiter that protects APIs by limiting requests (or consumed units such as LLM billing tokens or storage quota) per user, API key, tenant, or IP. It must support configurable rules (e.g., 100…

Also reported as: Design a Distributed Rate Limiter

Design Catalog Update Pipeline

Design a product catalog service for a large e-commerce marketplace that sustains heavy merchant writes (including bulk edits of millions of products and price updates) and very high user reads with low latency. Changes must…

Also reported as: Design autocomplete and merchant bulk edits

Design a Large-File Upload and Analysis Flow

Design a service that accepts large user uploads (files or product images, GBs in size), validates them, processes them asynchronously (virus scan, analysis, thumbnails, moderation), and makes results or approved assets available…

Design an ads event reporting system

Design an ad click and impression aggregation system. Ingest a high-volume stream of ad events ({ad_id, campaign_id, user_id, event_type, timestamp}, billions per day) and provide aggregated metrics (clicks, impressions, CTR per…