Web Server Tier vs. Worker Tier

 

Here's a clear comparison of Web Server Tier vs. Worker Tier in AWS Elastic Beanstalk — two different environment types twtech can use based on the nature of the application:

 Web Server Tier

 Purpose

Designed to run web applications that handle HTTP requests directly from clients (browsers, APIs, etc.).

 How It Works

• Accepts incoming HTTP(S) traffic through Elastic Load Balancer (ELB).
• Runs on EC2 instances behind the ELB.
• Ideal for websites, REST APIs, frontend-backend apps.

 Key Features

Feature	Description
Load Balancing	Built-in with ELB
Auto Scaling	Automatically adjusts instance count based on load
Routing	Receives traffic on standard ports (80, 443)
Health Checks	Monitored via HTTP endpoint
Supports HTTPS	Terminate SSL at the load balancer

 Use Cases

• Web portals
• RESTful APIs
• Web dashboards
• eCommerce sites
• Real-time web apps

 Worker Tier

 Purpose

Designed to run background tasks or asynchronous jobs triggered by messages from Amazon SQS (Simple Queue Service).

 How It Works

• Listens to an SQS queue.
• Picks up messages and processes them independently.
• Useful for offloading non-blocking, time-consuming operations.

 Key Features

Feature	Description
Queue Integration	Automatically polls a specified SQS queue
No ELB	Doesn’t receive HTTP requests from browsers
Concurrency	Runs multiple jobs in parallel (based on instance size and scaling config)
Asynchronous	Handles background/long-running jobs
Decoupled	Logic is separate from the user-facing app

 Use Cases

• Image/video processing
• Email sending
• Report generation
• Data transformation/ETL jobs
• Event-driven backend processes

 Key Differences Summary

Feature	Web Server Tier	Worker Tier
Traffic Type	HTTP/S	SQS Messages
Entry Point	ELB (Public)	SQS Queue
User Interaction	Yes	No
Primary Use	Serving web/API requests	Background processing
Load Balancer	Yes	No
Scaling	Based on HTTP traffic	Based on queue length/CPU
Example	A React frontend with Flask API	A job that sends batch emails from a queue