This is an HTTP POST endpoint. Any text/document you POST to this URL will be received by the user.
You must provide a From:
header (borrowed from SMTP), and can include other mail headers as well.
To send a plain text message:
curl --data-binary "Hello, world" --header "Content-Type: text/plain" \
--header "From: Somebody <somebody@example.com>" \
{{url}}
To send an inline picture:
curl --data-binary @small-image.png --header "Content-Type: image/png" \
--header "From: Somebody <somebody@example.com>" \
{{url}}
To send a picture (or other document) as an attachment:
curl --data-binary @large-image.jpg --header "Content-Type: image/jpeg" \
--header "Content-Disposition: attachment; filename=\"large-image.jpg\"" \
--header "From: Somebody <somebody@example.com>" \
{{url}}