curl

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

# POST with JSON body
curl -X POST https://api.example.com/users \
  -H "Content-Type: application/json" \
  -d '{"name": "Alice", "role": "admin"}'

# PUT
curl -X PUT https://api.example.com/users/1 \
  -H "Content-Type: application/json" \
  -d '{"name": "Alice Updated"}'

# DELETE
curl -X DELETE https://api.example.com/users/1

# Send form data
curl -X POST https://example.com/form \
  -F "username=alice" \
  -F "file=@/path/to/file.txt"

# Custom header
curl -H "X-API-Key: abc123" https://api.example.com

# Bearer token
curl -H "Authorization: Bearer <token>" https://api.example.com

# Basic auth
curl -u username:password https://api.example.com

# Multiple headers
curl \
  -H "Content-Type: application/json" \
  -H "Accept: application/json" \
  -H "X-Request-ID: abc123" \
  https://api.example.com

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

# Show both request and response headers
curl -v https://example.com

# Skip TLS verification (dev only)
curl -k https://self-signed.example.com

# Use custom CA certificate
curl --cacert /path/to/ca.crt https://internal.example.com

# Client certificate auth (mTLS)
curl --cert client.crt --key client.key \
  https://mtls.example.com

# Check TLS certificate details
curl -vI https://example.com 2>&1 | grep -A 10 "Server certificate"

# Connect with specific TLS version
curl --tls-max 1.2 https://example.com
curl --tlsv1.3 https://example.com

# Save to file (preserving filename)
curl -O https://example.com/file.zip

# Save to specific file
curl -o output.json https://api.example.com/data

# Follow redirects
curl -L https://example.com

# Silent mode (no progress bar)
curl -s https://api.example.com | jq '.'

# Show only HTTP status code
curl -s -o /dev/null -w "%{http_code}" https://example.com

# Resume interrupted download
curl -C - -O https://example.com/large-file.zip

# Verbose output (headers, TLS handshake)
curl -v https://example.com

# Timing breakdown
curl -w "\n
DNS:        %{time_namelookup}s
Connect:    %{time_connect}s
TLS:        %{time_appconnect}s
TTFB:       %{time_starttransfer}s
Total:      %{time_total}s\n" \
  -o /dev/null -s https://example.com

# Trace all data (very verbose)
curl --trace-ascii - https://example.com

# Show effective URL after redirects
curl -Ls -o /dev/null -w "%{url_effective}" https://example.com

# Retry on transient errors
curl --retry 3 --retry-delay 2 \
  --retry-connrefused https://api.example.com

# Connection timeout (seconds)
curl --connect-timeout 5 https://api.example.com

# Max total time
curl --max-time 30 https://api.example.com

# Use specific DNS resolver
curl --resolve example.com:443:1.2.3.4 https://example.com

# Send request to specific IP (test without DNS)
curl -H "Host: example.com" https://1.2.3.4

# Compress response
curl --compressed https://api.example.com

# Send cookies
curl -b "session=abc123" https://example.com