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Knowledge base

PMTA knowledge base›Block <signals>›Directive§ 11.1.6.2.5

enable-top-open-pixel

<signals>

Whether to track opens — by an image at the top of the message
in the configuration this is a lineenable-top-open-pixel 1inside the block <signals>
One of three insertions into the message

With tracking done by the engine, it inserts a transparent image at the beginning of the message. The line lets you turn this part off. The default is yes.

There are three insertions in all, and each is enabled separately: link clicks, an image at the top of the message and an image at the bottom. By default all are on.

The image at the top fires more often: messages are often not read to the end.

🔴 It works only with engagement-tracking set to sparkpost. With external you send the events yourself, and the engine has nothing to insert.

The main trap is turning it off and expecting the metric to remain. The service counts opens and clicks by these very insertions. By turning them off, you do not “reduce interference with the message” but deprive the analytics of half its data — including the health score.
What the Hub does. It does not write it — and does not intend to: inserting someone else’s links and images into our messages would mean recipients’ clicks and opens are recorded on the vendor’s side.
Recommended values

Individual insertions are turned off rarely and for a specific reason:

Value When
yes (default) tracking is on and needed in full
no this particular insertion interferes with the layout or a policy
The yes default and the condition “only with tracking done by the engine” come from the manual (§ 11.1.6.2.5). The remark about how the two images differ is ours.
Example configuration
# turning one insertion off, the other two keep working
<signals>
    engagement-tracking sparkpost
    enable-top-open-pixel no</signals>
The three insertions are independent: turning one off does not cancel the others.
yellow — — directive names, blue — blocks. They are highlighted the same way in the text of the card.
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Common mistakes and problems

what people get wrong and how it ends1 mistake▶

Turning off an insertion while counting on keeping the metric

our experience

What it costsThe metric is counted by the insertion. Without it the corresponding events will not exist at all, and the health score becomes incomplete.
How to spot itOpens or clicks in the reports dropped to zero.
How to do it rightReturn the default or accept that this metric will not exist.
Compatibility
PowerMTA 6.0
described in the manual of this version · platform: any
The vendor does not state the first version for every directive — there is no note here. The name also appears in the 5.0 edition of the manual.
Reference data
Syntax
enable-top-open-pixel yes | no
Values
yes | no | true | false
Default
1 § 11.1.6.2.5
Applying
reload, no restart needed
Queue
will not touch what is already queued
Where to write it
<signals>
How many times
once in the block
Everything here comes from the manual, with the section.
Inheritance
No inheritance: the line lives inside <signals>, and there is only one such block on a node. Insertions are not configured selectively per stream — only the scope of the whole export, with the enable-signals line.
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Related directives

1 relation

Works together with

enable-bottom-open-pixel<signals>The second image of the same pair: one at the top of the message, the other at the bottom. § 11.1.6.2.6

How to check on the node
It has to be checked on a delivered message — the insertion is either there or not:
grep -i "signals" /var/log/pmta/log | tail -20
It is more reliable to look at the message source in a seed mailbox: whether links are rewritten or not, whether images are inserted or not.
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What else to read

3 articles

◇Hand a message to a webhook instead of a receiverThe queue sends the message as a POST request in the form of a JSON object; only a 2xx response counts as success.◇The node can insert pixels and rewrite links by itselfIn the vendor’s tracking mode the engine parses outgoing HTML, rewrites links to the tracking domain and inserts open pixels — with a choice of what to do if the markup cannot be parsed.◇Markup parsing and editingOpen and click tracking in sparkpost mode edits the message markup with the built-in gumbo-parser; by default a message whose markup could not be parsed is bounced.

In the Hub
Cost of a mistake
safe: a wrong value breaks nothing
Scenarios
Tracking infrastructure
Neighboring settings of the block <signals>:html-edit-error-modetracking-domainengagement-trackingenable-click-trackingenable-bottom-open-pixelAll 16 directives of the block →