When submitting JSON payloads via REST API POST requests, servers may reject requests with 400 Bad Request or 415 Unsupported Media Type. Resolving REST HTTP POST failures requires validating JSON payload syntax, Content-Type headers, and CORS preflight OPTIONS behavior.

cURL Verification & Debugging Command

cURL Debugging Commandbash
# Test REST HTTP POST request with explicit JSON header and data payload
curl -i -X POST https://api.example.com/v1/posts \
  -H "Content-Type: application/json" \
  -H "Accept: application/json" \
  -d '{"title": "Test Title", "status": "published"}'