Zendesk Email Format
Your reply looks perfect in the agent interface and arrives with the logo four times the size. The Zendesk email format is why, and here's what to do about it.
What Zendesk actually sends
Every outbound notification is wrapped in an email template configured per brand. That template holds the HTML shell, the branding, and a placeholder where the comment content is dropped in. Zendesk sends a multipart message, so there is an HTML part and a plain text part, and the receiving client chooses.
This is the first thing people miss. Editing an individual macro doesn't change the wrapper, and editing the wrapper does not change the macro. If the logo is wrong, that is the template. If the wording is wrong, that's the macro or the trigger. The email templates guide covers where each lives.
The plain text part isn't decorative. Some clients and some corporate gateways will render it instead of the HTML, and if you leave it as generated markup stripped of tags it reads as garbage. Look at it at least once.
The rules of the Zendesk email format template
Email HTML isn't web HTML. It's roughly the web of twenty years ago, and the constraints are real.
<style> block in the head. Put the styles on the elements.Keep the required placeholders intact when you edit. Removing the one that renders the comment produces an email with beautiful branding and no message in it, which is a genuinely common mistake.
Signatures, and the delimiter that matters
Agent signatures are configured separately from the template and appended to the comment. They support placeholders for the agent name and other fields, so you can standardise the shape without asking sixty people to type it.
Keep them short and keep them text. A signature with a banner image, three social icons and a legal disclaimer is the single most common source of "why does this look broken on my phone" complaints. The agent signature guide covers the placeholder options.
The other half of this is the reply delimiter, the line telling the customer to type above it. Customers ignore it roughly half the time and reply underneath, which is how you get a ticket where the new content is buried below three screens of quoted history. Nothing fixes this completely. Making the delimiter visually obvious in both the HTML and the plain text part helps more than you'd expect.
What breaks in Outlook
Outlook on Windows has historically rendered mail with the Word engine rather than a browser engine, and the consequences are specific and well known to anyone who has built an email template.
Test before you ship, in real clients, not in a preview pane. Outlook on Windows, Gmail in a browser, Apple Mail on a phone. Those three cover most of what your customers use, and a template that survives all three will survive nearly everything else.
Before you blame the template
Two adjacent problems get misdiagnosed as formatting.
If mail is arriving mangled or not at all, check authentication before the HTML. Broken SPF or DKIM produces symptoms that look nothing like a DNS problem, and the email setup guide is the place to start.
And if you're building automated messages, keep the wording in dynamic content or macros rather than in the template itself, so tone changes do not become HTML edits. The email automation guide covers which rule should own which message.
Frequently asked questions
Why does the signature format break in some clients?
Because Zendesk email formatting is inlined HTML and clients strip what they dislike. The Zendesk email signature format survives best as simple markup, and Outlook is the one that breaks first.
Where do I edit the Zendesk email format template?
In the channel settings for email, per brand. It's separate from macros and triggers, which own the wording rather than the wrapper around it.
Does Zendesk send plain text email?
It sends multipart messages with both an HTML part and a plain text part. Some clients and gateways render the plain text one, so it's worth checking how it reads.
Why does our logo look huge in Outlook?
Outlook rescales images based on display settings. Set explicit width and height attributes on the image tag itself rather than relying on CSS alone.
Can I use CSS grid or flexbox in a Zendesk email?
Not reliably. Email clients are years behind browsers, so tables for layout and inline styles remain the safe approach.
Why do customers reply below the delimiter?
Because their mail client puts the cursor there. You cannot prevent it, but making the delimiter obvious in both the HTML and plain text parts reduces it noticeably.
When the reply never lands
Unread replies turn into second tickets. Ticket Merger catches the duplicate and merges it back into the original.
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