How to send GET and POST requests using cURL?

In cURL, GET and POST requests are the two most commonly used HTTP methods, each with different use cases and parameter configurations.

GET Request

GET requests are used to retrieve data, with parameters typically appended to the URL.

bash
# Basic GET request
curl https://api.example.com/users

# With query parameters
curl "https://api.example.com/users?page=1&limit=10"

# With request headers
curl -H "Authorization: Bearer token123" \
     -H "Accept: application/json" \
     https://api.example.com/users

# Show response headers
curl -i https://api.example.com/users

# Show only response headers
curl -I https://api.example.com/users

POST Request

POST requests are used to submit data, requiring -X POST to specify the method and -d to pass data.

bash
# Send JSON data
curl -X POST https://api.example.com/users \
  -H "Content-Type: application/json" \
  -d '{"name":"John","email":"john@example.com"}'

# Send form data
curl -X POST https://api.example.com/login \
  -d "username=admin&password=123456"

# Read data from file
curl -X POST https://api.example.com/upload \
  -H "Content-Type: application/json" \
  -d @data.json

# Upload file
curl -X POST https://api.example.com/upload \
  -F "file=@/path/to/file.pdf"

Key Differences

Feature	GET	POST
Data Location	URL parameters	Request body
Data Size	Limited by URL length	Unlimited
Security	Parameters visible	Relatively secure
Caching	Cacheable	Not cached
Idempotency	Idempotent	Non-idempotent

Common Parameters

• -X or --request: Specify HTTP method
• -H or --header: Add request header
• -d or --data: Send data
• -F or --form: Upload form/file
• -i: Show response headers and body
• -I: Show only response headers