•SYSTEM DESIGN
Pinterest System Design Questions
Every system design problem candidates reported at Pinterest between September 2025 and September 2026, most-asked first. Each one links to a full solution.
Problems
6
Candidate reports
10
Asked more than once
4
start here
Question type
6 HLD
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 worded 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 worded 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 worded 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 worded 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…
Duplicate reports of the same problem are merged and counted.
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What system design questions does Pinterest ask?
Candidates reported 6 distinct system design problems at Pinterest between September 2025 and September 2026, including Design a Typeahead Suggestion System, Design Comment Notifications with Viral-Pin Aggregation, Design a Distributed Rate-Limiting Service.
How to prepare for Pinterest system design interview?
Start with the Pinterest problems reported most often, work through each full solution, then practice explaining a design end to end under time pressure in a mock interview.
What is the difference between HLD and LLD at Pinterest?
HLD (High-Level Design) focuses on system architecture, scalability, and component interactions. LLD (Low-Level Design) dives into class diagrams, API contracts, and database schemas. Pinterest tests both.