MongoDB vs Redis
Complementary: MongoDB for persistent application data with ACID transactions, Redis for sub-millisecond caching and real-time. The standard architecture uses both together.
Quick Comparison
| Feature | MongoDB | Redis |
|---|---|---|
| Storage | Disk | RAM |
| Latency | 1-10ms | <1ms |
| Data Size | Petabytes | Limited by RAM |
| Queries | Complex | Key-value |
| Use Case | Primary database | Cache, real-time |
MongoDB
- Storage:
- Disk
- Latency:
- 1-10ms
- Data Size:
- Petabytes
- Queries:
- Complex
- Use Case:
- Primary database
Redis
- Storage:
- RAM
- Latency:
- <1ms
- Data Size:
- Limited by RAM
- Queries:
- Key-value
- Use Case:
- Cache, real-time
Interface Preview
MongoDB
Redis
Feature Comparison
| Feature | MongoDB | Redis |
|---|---|---|
| Core | ||
| Persistence | 5 | 3 |
| Query Speed | 3 | 5 |
| Query Complexity | 5 | 2 |
| Data Structures | 3 | 5 |
| Transactions | 5 | 2 |
| Scaling | ||
| Data Size | 5 | 2 |
| Horizontal Scaling | 5 | 4 |
| Pub/Sub | 2 | 5 |
| Caching | 2 | 5 |
| Managed Cloud | 5 | 4 |
Core
Persistence
Query Speed
Query Complexity
Data Structures
Transactions
Scaling
Data Size
Horizontal Scaling
Pub/Sub
Caching
Managed Cloud
Legend:
Our Verdict
Complementary: MongoDB for persistent application data with ACID transactions, Redis for sub-millisecond caching and real-time. The standard architecture uses both together.
💡 This verdict is based on general use cases. Your specific requirements, existing tech stack, and team expertise should guide your final decision.
Frequently Asked Questions
What are the primary use cases for MongoDB and Redis?
MongoDB is ideal for persistent application data with ACID transactions and complex queries, serving as a primary database for structured and unstructured data. Redis excels in sub-millisecond caching, real-time analytics, and session management due to its in-memory key-value structure, making it suitable for high-speed, temporary data storage.
How do MongoDB and Redis differ in terms of latency and performance?
MongoDB typically has latency of 1–10ms due to disk-based storage, while Redis achieves <1ms latency via in-memory operations. Redis outperforms MongoDB in read/write speed for simple key-value operations, but MongoDB handles complex queries and large-scale data persistence more effectively.
What are the storage differences between MongoDB and Redis?
MongoDB stores data on disk, supporting petabytes of storage for long-term persistence. Redis uses RAM, offering faster access but limited by available memory. This makes Redis ideal for temporary, high-speed data, while MongoDB is suited for durable, scalable storage of structured and unstructured data.
How can MongoDB and Redis be used together in an application?
MongoDB and Redis are often paired in architectures where Redis caches frequent queries or session data for speed, while MongoDB manages primary data storage. This combination leverages Redis’s low-latency performance and MongoDB’s ACID compliance, ensuring both real-time responsiveness and durable data persistence.