What is Rate Limiting?
Rate limiting is a technique that controls the number of requests a client can make to an API within a time window, protecting against abuse, DDoS attacks, and ensuring fair usage.
Rate Limiting Explained
Rate limiting controls how many requests a client can make to your API within a given time period. For example, '100 requests per minute per user.' When a client exceeds the limit, the API returns a 429 (Too Many Requests) status code. Rate limiting is essential for API security, preventing abuse (scraping, brute force attacks), protecting server resources, and ensuring fair usage among clients. Common algorithms include token bucket, sliding window, and fixed window. At M3L Software, we implement rate limiting in every production API. Our implementations use Redis for distributed rate limiting across multiple server instances, with configurable limits per endpoint, per user, and per IP address.
Key Features
Common Use Cases
Frequently Asked Questions
What rate limits should I set?
It depends on your API. Common starting points: 100 requests/minute for authenticated users, 20/minute for unauthenticated, 5/minute for login endpoints. Monitor usage patterns and adjust.
How does rate limiting work with multiple servers?
Use a shared store like Redis to track request counts across all server instances. Without shared storage, each server would have its own count, allowing limits to be bypassed.
Can rate limiting prevent DDoS attacks?
Rate limiting is one layer of DDoS protection but isn't sufficient alone. Combine it with CDN-level protection (Cloudflare), IP blocking, and infrastructure-level DDoS mitigation.
Related Terms
API
An Application Programming Interface (API) is a set of rules and protocols that allows different software applications to communicate with each other, enabling data exchange and functionality sharing.
Read moreREST API
A REST API (Representational State Transfer) is an architectural style for building web APIs that uses standard HTTP methods (GET, POST, PUT, DELETE) to perform operations on resources identified by URLs.
Read moreRedis
Redis is an open-source, in-memory data store used as a database, cache, message broker, and streaming engine, known for sub-millisecond response times.
Read moreFastAPI
FastAPI is a modern, high-performance Python web framework for building APIs, known for its speed, automatic documentation, and type-hint-based validation using Pydantic.
Read moreCORS
Cross-Origin Resource Sharing (CORS) is a browser security mechanism that controls which domains can make requests to your API, preventing unauthorized cross-origin access.
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