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Sender

property Sender: TIdEmailAddressItem read write;

Example​

procedure SetResponsibleSender;
var
  Msg: TIdMessage;
begin
  Msg := Email;
  if Msg = nil then Exit;

  Msg.Sender.Text := 'Velox Mailer <mailer@example.invalid>';
end;

Usage​

Holds the single Sender header identity and takes precedence over the first From address for Velox's default SMTP MAIL FROM envelope.

Additional Technical Info​

Sender returns one live TIdEMailAddressItem owned directly by the message. It is distinct from the author list in FromList: RFC message semantics use Sender for the agent responsible for transmission when that differs from the author(s).

Assignment copies Address and Name into the existing object; it does not replace ownership. Direct edits mutate the same borrowed item. Nil assignment is not guarded, and Text parsing is permissive rather than validating.

GenerateHeader encodes the item into the Sender header. ProcessHeaders assigns raw Sender directly through the item's Text parser. Unlike list fields, it does not subsequently call the encoded-display-name decoder, so an encoded word can remain in Name after loading. ClearHeader empties Sender.Text but retains the item.

Indy's default SMTP send trims Sender.Address and uses it as MAIL FROM when nonempty. Otherwise it trims the Address of From, which can create a blank first FromList item as a read side effect. Only the raw Address is used for this envelope choice; the display Name is irrelevant. Custom send overloads can supply another envelope sender, including an empty bounce sender.

Header Sender, From authors and SMTP MAIL FROM serve different purposes and may legitimately differ, but careless mismatch can fail anti-spoofing policy or confuse operators. Validate domains and authorization before sending. NoEncode skips the generated Sender header while the transport may still use this property for its envelope sender.

The example uses .invalid and was source-reviewed only; no network operation occurred.

External references

Created 2026-07-15