Pinterest System Design

Pinterest is a widely used visual discovery platform where users can explore, save, and share images (called "Pins"). In this article, we’ll go through the fundamental aspects of Pinterest’s system design, covering requirements, architecture, data storage, performance, and accessibility.

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General Requirements

1. Pins should be arranged using a Masonry Layout.

2. Users can view full details of a Pin.

3. Pins support images and GIFs, but not videos.

4. Users can post comments on Pins.

5. Users can share Pins.

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Functional Requirements

1. No support for Internet Explorer 11+.

2. Supports 95% of modern browsers.

3. Works on mobile, desktop, and other devices.

4. Offline mode support.

5. Should function even with low network bandwidth.

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Component Architecture

Pinterest follows a component-based architecture to handle different functionalities like rendering Pins, handling user interactions, and managing API calls. Below are some key components:

• Pin Board - Displays the Pins in a structured way.

• User Profile - Manages user-specific data and Pins.

• Comments Section - Allows users to engage with Pins.

• Sharing Mechanism - Handles Pin sharing across platforms.

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Masonry Layout

The Masonry Layout is a key aspect of Pinterest's design. Instead of a standard grid, it arranges Pins in columns with varying heights, ensuring a visually appealing and optimized layout. This is achieved using CSS Grid or JavaScript libraries like Masonry.js.

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Basic Data Entities layout

Pinterest manages several core data entities:

// Pin Object
 type Pin = {
  id: string;
  origin: PinBoard;
  description: string;
  title: string;
  imageUrl: string;
  author: User;
};

// Comment Object
 type Comment = {
  id: string;
  content: string;
  nickname: string;
};

// User Object
 type User = {
  id: string;
  nickname: string;
};

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Data API

Pinterest provides APIs to fetch and interact with Pins and comments:

getPins(api_key, user_id, includeComments, cursor, minID);
getComments(api_key, pin_id, page);

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Data Storage and Layers

Pinterest uses a multi-layered storage system for optimized performance. The layers include:

• Caching Layer for quick access.

• Database Layer for storing persistent user and Pin data.

• CDN (Content Delivery Network) for serving images efficiently.

  

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Performance Optimization

Network Performance

1. Uses GZIP (40-50% reduction) and Brotli (10-20% reduction).

2. Implements HTTP2 for efficient asset loading.

3. Uses WebP format for images to reduce size.

4. Lazy loading for Pins and images.

   

Rendering Performance

1. Inline critical CSS & JS to speed up rendering.

2. Uses pre-connect and DNS resolution to speed up network requests.

3. Loads analytics scripts after page load to prevent blocking.

4. Optimized CSS naming conventions.

JavaScript Performance

1. Minimizes redundant computations (Do Less Stuff principle).

2. Uses asynchronous operations where possible.

3. Implements caching for heavy computations.

4. Leverages Web Workers for background processing.

   

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Accessibility

Pinterest ensures accessibility by implementing:

1. Keyboard Navigation:

   • Add a Pin

   • Scroll to top/bottom

   • Share a Pin

   • Quick access menu

   • Help section

2. Color Themes for different vision needs.

3. ARIA Live Announcements for dynamic content.

4. Using rem units instead of pixels for better scaling.

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Conclusion

This article covered the basic system design of Pinterest, focusing on its architecture, data handling, performance, and accessibility. While this is a simplified version, Pinterest's real-world implementation involves scalability, microservices, and AI-based recommendations.

If you found this helpful, stay tuned for a more in-depth system design breakdown!