# Polling vs Streaming: Data Updates in Real-Time Systems

# Introduction

In today's apps, especially ones that need live updates like monitoring systems, financial tickers, or chat apps, it's important to handle data flow between servers and clients well.

**The two main ways to do this are polling and streaming.**

# Polling

Polling is a technique where the client periodically requests data from the server at set intervals. This method is straightforward and easy to implement but comes with trade-offs regarding resource usage and real-time efficiency.

## How It Works

1. **Request Cycle**: The client sends a request to the server asking for the latest data.
    
2. **Server Response**: The server processes the request and sends back the data.
    
3. **Wait**: The client waits for a predefined interval before sending another request.
    

## Diagram

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1709317370923/1a1cf582-3c0e-4076-83ee-9994db419a25.png align="center")

## When to Use Polling

* **Low-Frequency Updates**: Best for when data doesn't change often and keeping a constant connection isn't worth it.
    
* **Simplicity**: Good for apps that value simplicity and want to use minimal server resources.
    

# Streaming

Streaming allows for an open, long-lived connection between the client and the server. With this approach, the server can "push" updates to the client in real-time as soon as new data is available, eliminating the need for repeated requests.

## How It Works

1. **Open Connection**: The client starts a connection with the server, usually using WebSockets, making a persistent link.
    
2. **Data Push**: Whenever new data is available, the server immediately sends updates to the client without waiting for a request.
    
3. **Continuous Updates**: The client receives data as soon as it's available, ensuring real-time updates.
    

## Diagram

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1709317481549/fae48cbf-6837-43fd-a018-b6aa23d45788.png align="center")

## When to Use Streaming

* **Real-Time Applications**: Important for situations where instant updates are needed, like chat apps or live stock trading sites.
    
* **High-Frequency Updates**: Ideal for places where information changes quickly and all the time.
    

# Choosing Between Polling and Streaming

Choosing between polling and streaming for your app depends on a few things:

* **Data Update Frequency**: Use streaming for data that changes often, and polling for data that doesn't change much.
    
* **Resource Constraints**: Polling is easier to set up but can waste resources if updates are frequent. Streaming is harder to set up but is better for saving resources in real-time situations.
    
* **Application Requirements**: What your app does and how quickly it needs data updates will greatly affect your decision.