X-Message-ID
Analytics. A custom Simple Mail Transfer Protocol (SMTP) email header that Twilio SendGrid includes in email messages it sends as event webhook metadata.
The following image depicts a typical response received after a message has been sent:
This response includes the X-Message-ID header. Use this header to track events that the Event Webhook posts.
To correlate to your Event Webhook data and help troubleshooting, store this X-Message-ID header data.