30.12 Size filter

30.12.1 Overview

The size filter checks the size of individual attachments in bytes, kilobytes, or megabytes. It selectively targets very small (small images, logos) or very large attachments (extensive supplier packages).


30.12.2 Property

Property Matches
Attachment size Size of a single attachment (per attachment)

Note: The filter is evaluated per attachment - the mail matches as soon as at least one attachment satisfies the condition.


30.12.3 Operators and units

Operator Description
less than Size below threshold
greater than Size above threshold
is between Value 1 to Value 2
Unit Meaning
Bytes Raw bytes
KB Kilobytes (1,024 bytes)
MB Megabytes (1,048,576 bytes)

With is between, both values can have different units (e.g. “between 50 KB and 5 MB”).


30.12.4 Use cases

Store large attachments specifically

Attachment size greater than 1 MB
AND Attachment name ends with .zip<OR>.pdf

Special route for large supplier packages - only attachments of 1 MB or more land on a fast drive.

Exclude advertising images

Attachment name ends with .jpg<OR>.png
AND Attachment size greater than 50 KB

Reduces matches to relevant business attachments - tracking pixels and small logos are filtered out.


30.12.5 Tip

  • With IMAP, the server provides the size immediately. With POP3, the attachment must be partially loaded - for pure size filters on POP3, processing is slower