How do I add the ticket ID to the subject line

Yes, with the ticket ID placeholder in the subject of your notification triggers. Zendesk's own threading does not depend on it, and your customer's inbox does.

Yes, with the ticket ID placeholder in the subject of your notification triggers. Zendesk's own threading does not depend on it, and your customer's inbox does.

How do I put the ticket number in the subject?

Edit the triggers that send notifications and add {{ticket.id}} to the subject line, usually in brackets at the front or the back. Plain {{ticket.id}} writes the number as text; #{{ticket.id}} makes it a clickable link. Every notification from then on carries it.

Why teams want it

Customers can quote a number when they phone, and their own colleagues can search for it. For a business customer dealing with several suppliers at once, that is genuinely useful.

What should I check first?

Two things, and the first is not what people expect.

Threading is safer than it looks

Zendesk threads incoming replies onto the right ticket using {{ticket.encoded_id}}, not the subject, so your own threading is not at risk. What does depend on the subject is the customer's mail client, which groups a conversation partly by it. A consistent format keeps their thread together, and changing the format later splits the threads they already have.

Length, and deciding once

The subject is what people see in a list. A number plus a long original subject gets cut off, and it is the informative half that disappears. So pick a format and keep it: change it later and customers end up with two shapes of subject line for one account, and the filters they quietly built stop working.

See also

• Ticket IDs: where they come from and how to change the starting number
• Customising email templates
• What placeholders are