# Documentation

### Kafka 2.1 Documentation

Prior releases: 0.7.x, 0.8.0, 0.8.1.X, 0.8.2.X, 0.9.0.X, 0.10.0.X, 0.10.1.X, 0.10.2.X, 0.11.0.X, 1.0.X, 1.1.X, 2.0.X.

## 1. Getting Started

### 1.1 Introduction

### 1.2 Use Cases

### 1.3 Quick Start

### 1.4 Ecosystem

### 1.5 Upgrading From Previous Versions

## 2. APIs

## 3. Configuration

## 4. Design

## 5. Implementation

## 6. Operations

## 7. Security

## 8. Kafka Connect

## 9. Kafka Streams

Kafka Streams is a client library for processing and analyzing data stored in Kafka. It builds upon important stream processing concepts such as properly distinguishing between event time and processing time, windowing support, exactly-once processing semantics and simple yet efficient management of application state.

Kafka Streams has a low barrier to entry: You can quickly write and run a small-scale proof-of-concept on a single machine; and you only need to run additional instances of your application on multiple machines to scale up to high-volume production workloads. Kafka Streams transparently handles the load balancing of multiple instances of the same application by leveraging Kafka's parallelism model.

Learn More about Kafka Streams read this Section.