SMTP250 is a service from ADHOCON GmbH for people who want a record of what the recipient mail server acknowledged. Use your existing mail client. Change name@example.org to name#example.org@smtp250.org, send your message, then confirm the card reservation link. Capture happens only after an observed external SMTP 250 acceptance. The original sender receives a single signed PDF with the complete JSON dataset printed on it and an embedded document signature. To try the format for free, include the standalone word DEMO in your subject. You receive a sample PDF containing your test message’s details; the original is not forwarded and no money is reserved. This is a technical acceptance record, not proof that someone read the email, not an inbox guarantee, and not a blanket promise of legal effect. The signature is from the operator, not a qualified electronic signature; there is no independent trusted timestamp. The website and service messages are currently primarily in German. Temporary storage, retries and failure handling are explained on the website. Feedback on the workflow is welcome at promo@smtp250.org.

SMTP250

Signed PDF records of recipient mail server acceptance

Signed PDF records of recipient mail server acceptance