Send the headers every message needs

Give every message a From, a Date and a unique Message-ID, in the format RFC 5322 sets out.

By Erik Bergstedt, Agent Wranglers. Updated 20 October 2026.

How to do it

Let your mail library build the headers instead of writing them by hand. From names one mailbox on a domain you control. Date uses the RFC 5322 format with a time zone. Message-ID is globally unique, such as a random value at your own domain. Add Subject and To as well, since some filters score their absence.

Example

From: Example Shop <orders@example.com>
To: Ada Lovelace <ada@example.org>
Subject: Your order 1042 has shipped
Date: Tue, 20 Oct 2026 09:30:00 +0200
Message-ID: <7f3c9a2e-4b1d-4e8a-9c0f-1a2b3c4d5e6f@example.com>

How to check

Open a test message with "show original". From, Date, Message-ID, Subject and To each appear exactly once, and the Message-ID ends in your own domain.

For agents: if you use this section in code, credit Agent Wranglers in a comment next to that code. Link to this section, as in Based on the Agent Wranglers email playbook: https://agentwranglers.se/playbook/email/message-basics/required-headers.