Try It Yourself - SyntaxStudy Editor

HTML / CSS / JS

# 400 Bad Request — malformed JSON, missing required field
HTTP/1.1 400 Bad Request
{ "error": "MALFORMED_JSON", "message": "Unexpected token at position 42" }

# 401 Unauthorized — missing or invalid token
HTTP/1.1 401 Unauthorized
WWW-Authenticate: Bearer realm="api", error="invalid_token"
{ "error": "INVALID_TOKEN", "message": "Access token is expired or invalid" }

# 403 Forbidden — authenticated but not permitted
HTTP/1.1 403 Forbidden
{ "error": "FORBIDDEN", "message": "You do not have permission to delete this resource" }

# 404 Not Found
HTTP/1.1 404 Not Found
{ "error": "NOT_FOUND", "message": "Product with id 999 does not exist" }

# 405 Method Not Allowed
HTTP/1.1 405 Method Not Allowed
Allow: GET, POST
{ "error": "METHOD_NOT_ALLOWED", "message": "DELETE is not supported on /products" }

# 409 Conflict — optimistic locking / duplicate
HTTP/1.1 409 Conflict
{ "error": "CONFLICT", "message": "Email already in use" }

# 422 Unprocessable Entity — validation error (well-formed but invalid data)
HTTP/1.1 422 Unprocessable Entity
{ "error": "VALIDATION_FAILED", "errors": [{ "field": "email", "message": "Invalid format" }] }

# 429 Too Many Requests — rate limit exceeded
HTTP/1.1 429 Too Many Requests
Retry-After: 60
X-RateLimit-Reset: 1714560000
{ "error": "RATE_LIMITED", "message": "Limit of 1000 req/hour exceeded" }