Pinterest’s impressive growth to 11 million users with only a small team of engineers raises the question: how did they manage such an expansion? The answer lies in a four-stage scaling process. In this article, we’ll explore Pinterest’s growth journey and uncover how they overcame complex challenges to succeed. Through this process, you can gain new insights into scalable architecture design and growth strategies.
Starting with a Small Team
Pinterest’s growth began with a small team of engineers who quickly built prototypes of the product and rapidly responded to user needs. At the time, flexibility and quick responses were crucial, allowing them to incorporate user feedback in real-time.
Challenges from Rapid User Growth
As Pinterest grew rapidly, so did the number of users, which highlighted the limitations of their system. They recognized the need to transition to a more scalable architecture. This challenge is one that many startups face—rapid growth often brings system complexity and technical debt.
Adopting a Stable Architecture
As Pinterest matured, they adopted scalable technologies like MySQL, Memcache, and Redis. MySQL was chosen for its stability and ease of maintenance, Memcache helped relieve the database by caching frequently accessed data in memory, and Redis provided flexibility to handle various data structures.
During this period, Pinterest built a simple yet scalable architecture, which became a critical turning point for their technical and business growth.
Horizontal Scaling with a Stable System
With a stable architecture in place, Pinterest focused on horizontal scaling, adding resources as their user base grew. This allowed them to continue growing without introducing further complexity. Horizontal scaling is a common strategy among today’s major platforms.
Database Scaling: Clustering vs. Sharding
Another key strategy Pinterest adopted was sharding, rather than clustering, to scale their database. Sharding, where data is split into chunks and stored across independent servers, allowed for simple architecture and independent scaling. However, it also made it difficult to handle database-level joins and transactions, increasing application complexity.
A Gradual Approach
Pinterest approached their transition from a legacy architecture to a sharded architecture cautiously, following several important steps:
- Removed all MySQL joins and aggressively utilized data denormalization and caching.
- Simplified data routing through a 64-bit ID-based sharding system.
This transformation happened gradually during a feature freeze period, which allowed them to manage data migration and application logic changes smoothly.
Challenges and Solutions of Sharding
Despite the benefits, Pinterest faced challenges with sharding. Migration scripts took time, maintaining data consistency was difficult, and schema changes had to be applied across all shards. Even generating reports across shards posed challenges.
However, Pinterest overcame these obstacles through careful planning and incremental changes, ensuring stable scalability.
Conclusion: Simplicity Is Key to Scalability
The most important lesson from Pinterest’s growth journey is that simplicity is the key to scalability. Simple, understandable technology and architecture make problem-solving easier and provide a foundation for stability even in rapid-growth environments.
For any growing business, choosing a simple but scalable system is essential. It enables both scalability and stability, playing a crucial role in achieving sustainable growth.
Reference: Devansh, “How Pinterest Scaled to 11 Million Users With Only 6 Engineers”