Unique message identifier; constant on retries.
UNIX timestamp (seconds) when the webhook was sent.
HMAC-SHA256 signature(s) over "{id}.{timestamp}.{payload}". Format: space-delimited list of "v
false
PDF_GENERATION_FAILED Correlation ID from original request
async Maps to HTTP status code class
500 Specific error subcode
"PDF_GENERATION_FAILED"
Human-readable error message
Optional extra debug info
Optional structured data
{
"requiredCredits": 1,
"availableCredits": 0,
"issues": []
}Receipt acknowledged