Rate Limiter Service

A lightweight, extensible, and production-ready rate limiting system built with Spring Boot. This project implements three classic rate-limiting algorithms:

• Fixed Window
• Sliding Window
• Token Bucket

You can switch between algorithms easily by enabling the corresponding service in the filter.

Features

• Three fully implemented rate limiter strategies
• Configurable request limits via application.properties
• IP-based rate limiting (request.getRemoteAddr())
• Global filter using OncePerRequestFilter
• Plug-and-play architecture (swap algorithms instantly)
• Example endpoint /limiter/api/check

Implemented Algorithms

1. Fixed Window Rate Limiting

• Divides time into fixed windows (e.g., 1 minute)
• Tracks how many requests occur in each window
• Simple but can cause burst issues at window boundaries

Best for: Basic API throttling, simple enforcement rules.

2. Sliding Window Rate Limiting

• Stores exact timestamps of requests inside a queue
• Removes timestamps older than the window
• More accurate than Fixed Window

Best for: Fairer request distribution without boundary spikes.

3. Token Bucket Rate Limiting

• Bucket holds tokens up to a maximum capacity
• Tokens refill every second
• Each request consumes one token
• Allows configurable bursts

Best for: APIs that need flexibility + burst handling.

Running the Project

Requirements

• Java 17+
• Maven 3+
• Spring Boot 3.x Command

mvn spring-boot:run