When a /send request is successful, you'll receive an HTTP 200 response back.
This DO NOT mean that the message is received by the recipient.
What does this mean?
- When we send a message to the sender's SMTP server, it sends us a confirmation that it received the message and will process it further. That's when we send the 200 response back.
- A 200 status code means that we have delivered the request to the provider. Now it's up to the provider to send it forward. In the case of sending a message, this means that there is no real way to know if the message has been delivered or not except for open tracking.
- If the message isn't delivered it is up to the provider to send back a bounced message or not. If you receive a bounce message it should be in the same thread as the original sent message. If a bounced message isn't received, the user would have to reach out to their email admin.