cURL Cookbook

Why cURL matters

cURL is the fastest way to reproduce API requests from terminals, CI pipelines, and bug reports. A good cURL snippet is a portable “truth source” for debugging.

GET request

curl -i https://example.com/api/users/42

GET with headers

curl -i 
  -H "Accept: application/json" 
  https://example.com/api/users/42

Bearer token

curl -i 
  -H "Authorization: Bearer <access_token>" 
  -H "Accept: application/json" 
  https://example.com/api/me

POST JSON

curl -i 
  -X POST https://example.com/api/orders 
  -H "Content-Type: application/json" 
  -H "Accept: application/json" 
  -d "{ "productId": 123, "quantity": 2 }"

PATCH JSON (partial update)

curl -i 
  -X PATCH https://example.com/api/users/42 
  -H "Content-Type: application/json" 
  -H "Accept: application/json" 
  -d "{ "name": "Ada" }"

PUT JSON (replace)

curl -i 
  -X PUT https://example.com/api/users/42 
  -H "Content-Type: application/json" 
  -H "Accept: application/json" 
  -d "{ "id": 42, "name": "Ada" }"

DELETE

curl -i -X DELETE https://example.com/api/users/42

Send query parameters

curl -i "https://example.com/api/orders?status=paid&limit=20"

Upload a file (multipart)

curl -i 
  -X POST https://example.com/api/uploads 
  -H "Accept: application/json" 
  -F "file=@./image.png"

Download a file

curl -L -o output.zip https://example.com/api/exports/latest

Debugging tips

• Use -i to include headers in output.
• Use -v for verbose network details.
• Use --compressed to support gzip/brotli responses.
• Use --fail-with-body (newer curl) to fail non-2xx while keeping the response body.

Checklist

• Always set Content-Type when sending JSON.
• Use Authorization header for credentials.
• Capture both request and response when reporting bugs.