Allowing attachments in tickets

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Verified AI summary ◀▼
Enable attachments in tickets to allow agents and end users to share files through various channels. Configure settings for email attachments, file types, privacy, and expiration periods to control access and security. Manage attachment size limits and ensure files are scanned for malware. Customize permissions to enhance ticket interactions while maintaining data security.





Location: Admin Center > Objects and rules > Tickets >
Settings

Agents and end users can send each other attachments through tickets. Zendesk
Support accepts attachments from users sent in via the API, email, web form,
Web Widget, and Web Widget (Classic) channels in your help center.
Administrators can configure how attachments are handled in a number of ways,
including setting privacy rules, end user permissions, and attachment
methods.
This article includes the following topics:

About email attachments
Allowing agents to attach files in emails
Allowing end users to attach files to tickets
Allowing private attachments
Setting an expiration period for public attachments
Setting allowed file types for attachments
Attachment size limitations



About email attachments

Agents and end users can add attachments when creating or updating a
ticket, or replying to an email notification. The attachments become
linked attachments, which are links to external files
that can be used to download the attachments, if and when they’re
needed. This is the default behavior for attachments sent by email
and this is what happens when email attachments are not allowed.
If email attachments are allowed, the behavior is different.
Agents and end users can send email attachments instead of linked
attachments. Email notifications caused by creating or updating a
ticket, or replying to an email, include actual attachments, instead
of links to attachments. Email attachments appear as images and are
a preview of the first page of the file.
There are two types of email attachments:

Inline attachment: You can drag and drop files
into the body of an email or comment. The image of
the file appears wherever you dropped the file.

Appended attachment: Attachments that appear at
the bottom of a comment and that send as part of the
comment's email notification.



Note: If you've set up business rules to send automated replies to end users
(with placeholders such as
ticket.verbatim_description), any
attachments originally sent by the end user will not be included in
the automated email notification.
All files attached via email are scanned for malware before being sent in
an email notification. If an attachment is found to include a virus,
several actions are taken. The attachment:
Isn't included in the email notification. Instead, the
recipient is notified that an attachment wasn't
sent.
Won't be visible within the ticket to end users.
Will be visible within the ticket to agents but labeled
with a malware warning and unavailable for
download.
Will be visible within the ticket to admins but labeled
with a malware warning. Admins can download
potentially malicious attachments and choose to
override the restricted access for agents.


The sender does not receive a notification when an attachment
is not sent.
When email attachment file size limitations are
exceeded, links to attachments appear in email notifications instead
(see Attachment size limitations).

Note: Some
attachments may initiate Zendesk firewall rules. For
example, if your attachment contains code, the firewall rule
may be initiated. Zendesk recommends you zip or encrypt the
file to bypass this rule.
Here are examples of what attachments look like to agents and end
users.








Situation
Example





Linked email attachment in an email
notification in Gmail account







Email attachment in an email notification in
Gmail account







Attachment in the ticket interface in
Support






Malicious attachment in the ticket
interface in Support (visible only to team
members)








Allowing agents to attach files in emails

The default attachment configuration allows your agents to add files to
ticket comments and email notifications as links. You can allow
agents to attach files directly to the comment. This type of
attachment is stored in Zendesk Support and is accessible from the
ticket interface. You can attach any file type you want.


Note: The types of comment
placeholders you use in ticket triggers can
also affect whether email attachments appear as links. Use
rich text comment placeholders to allow attachments when
Allow agents to attach files in emails is
turned on.

You can also allow end users to add attachments to tickets (see Allowing end users to attach files to tickets).

To allow email attachments
In Admin Center, click
Objects and rules in the sidebar, then select Tickets > Settings.
Click Downloads and attachments to expand
it.
Select Allow agents to attach files in
emails.
Note: This
setting doesn't appear and can't be turned on if
secure downloads are allowed.

At the bottom of the page, click Save.


Once turned on, when an agent attaches a file to a comment, it is
included as an attachment rather than a link. Only files attached to
the current ticket comment are included in the email notification.
Files attached to earlier ticket comments are not attached to later
email notifications.
For information about how to send an attachment as an agent, see Adding attachments to ticket
comments.



Allowing end users to attach files to tickets

You can allow end users to send attachments when filing a ticket or
responding to an email notification. In addition, you can set
end-user attachments as private, requiring agent authentication for
files uploaded by end users.
The permissions granted to agents, described in Allowing agents to attach files in emails, apply to end
users when this setting is configured. Additionally, inline
attachments are available only for signed-in end users.

To allow attachments from end users
In Admin Center, click
Objects and rules in the sidebar, then select Tickets > Settings.
Click Downloads and attachments to expand
it.
Select Allow end users to attach
files.
Select Private end user attachments to require
agent authentication when accessing
customer-provided files, preventing unauthorized
access. If Allow secure downloads is
turned off, agent-uploaded attachments remain
accessible to end users without requiring a
sign-in or a Zendesk account.
For
information about using secure attachments in
messaging tickets, see Turning on private
attachments in messaging.

Click Save.





Allowing private attachments

Attachments usually aren't indexed by search engines or included in
threat intelligence platforms (TIPs) unless their URLs are publicly
shared, like in a help center article or within email notifications
to users. Regular attachments to tickets are secured using a URL
with an attachment token that is considerably complex and random,
but are visible to anyone with the URL and token. When relying on
this type of security, if an email notification is misdirected to
someone other than the intended end user, sensitive information may
be accidentally exposed.
If sensitive documents are attached to your tickets, especially
identification documents such as passports and driver's licenses,
you can allow private attachments. When turned on, agents must be
signed in to view attachments.
End users can see private attachments in their tickets in help center
because they have to sign in to view their tickets. However, the attachments
will appear as links in email tickets. They'll need to click the links and sign in
to the help center to view the attachments.
Note the following about allowing private attachments:

Private attachments can only be used if Guide is activated. If
Guide isn't activated, private attachments prevent end users
from downloading attachments since they can't be
authenticated.
If you allow private attachments, it will disable inline images
for users who aren't signed in, and it will also prevent
agents and admins from being able to add inline images in
Support. Inline images are disabled only for Zendesk hosted
images and not images that are publicly accessible.
When an attachment is associated with a ticket, visibility is
restricted to users with access to the ticket.


In the Zendesk Agent Workspace, this setting also applies to
attachments sent as part of a live chat, but it does not
apply to web, mobile, or social messaging attachments (see
Securing chat
attachments in the Zendesk Agent
Workspace).
To allow private attachments for messaging, see About private
attachments in messaging.



Note: Access controls should be implemented to
ensure only authorized personnel can view sensitive
attachments, and staff should be educated on the importance
of data security and the proper handling of attachments. See
General security best
practices for more information about keeping
your Zendesk account secure.

To allow private attachments

In Admin Center, click
Objects and rules in the sidebar, then select Tickets > Settings.
Click Downloads and attachments to expand it.
Select Allow secure downloads.
Note: Allow agents to
attach files in emails doesn't appear and
can't be turned on if secure downloads are allowed.
Additionally, when you turn on secure downloads,
agents can't copy and paste images from their
computer into ticket comments.


Click Save.




Setting an expiration period for public attachments

Admins can turn on an expiration period for agent-uploaded public
attachments. Attachment expiration allows agent-uploaded attachments
to remain publicly accessible for a designated period, after which
they become private and require user authentication to access.
This feature applies only to agent-uploaded files hosted as URL links.
Therefore, if your security policy requires all agent-uploaded files
to expire, you must turn on Attachment expiration and turn
off Allow agents to
attach files in emails.
Attachment expiration for public attachments provides an alternative to
private
attachments, which require end users to authenticate
before accessing attachments. This feature is particularly
beneficial for organizations with large end-user bases that prefer
not having authentication barriers for attachment access.
When this feature is turned on, agent-uploaded attachments remain
publicly accessible for 24 hours by default, but the timeframe can
be changed. When the expiration period lapses, attachments are
private and require user authentication for access.
This feature doesn't apply to files attached directly to ticket comments
as real attachments, images attached to macros, or images embedded
within macro comments.
To turn on an expiration period for public attachments

In Admin Center, click
Objects and rules in the sidebar, then select Tickets > Settings.
Click Downloads and attachments to expand it.
Select Attachment expiration.
Note: Attachment expiration is hidden if
Allow secure downloads is turned
on.

In the Hours field, enter the number of hours to keep
attachments public. After this time period, the attachment
can only be accessed through a secure link that requires
sign-in.
Click Save.




Setting allowed file types for attachments

By default, when ticket attachments are turned on, attachments are
restricted to a recommended list of commonly used file extensions
that are generally considered safe. This helps protect your account
from potentially harmful files such as .exe attachments, which are
often exploited in security attacks.

Note: If your account was created before August 13,
2025, all attachment file extension types are allowed by
default.
The list of recommended file types includes the following file
formats:
har, json, 3g2, 3gp, 7z, aac, amr, avi, bmp, csv, doc, docx, eml,
gif, heic, heif, ics, jfif, jpeg, jpg, key, log, m4a, m4v,
mov, mp3, mp4, mp4a, mpeg, mpg, mpga, neon, numbers, odt,
oga, ogg, ogv, opus, pages, pdf, png, pps, ppsx, ppt, pptx,
qt, svg, tif, tiff, txt, vcf, wav, webm, webp, wmv, xls,
xlsx, xml, yaml, yml, zip
You can change this setting to allow all file types or create a custom
list of allowed file types. When you change the setting, existing
tickets and attachments are not affected retroactively.

Note: Zendesk uses industry-standard detection to
verify files based on their internal format, rather than just the
file extension. This provides flexibility; even if a file is
mislabeled (for example, a JPG file manually renamed to a PNG),
Zendesk will still recognize and accept it. As long as the file type
itself is one Zendesk supports, the upload will succeed.
File type restrictions apply to files attached to new tickets created
through these channels:


Email
Help center Submit a request form
Zendesk Support mobile app
Web Widget (Classic)


When attachment file types are restricted, agents receive an error
message if they attempt to attach a file with a disallowed
extension, a mismatched file type and extension, or a missing file
extension.

End users don't see an error if they attach a disallowed file. Instead, a
ticket is created without the attachment. Agents see a warning in
the ticket conversation and ticket events that
explains why the attachment wasn't included. This is true even if
the disallowed file was the only content in the ticket.

Zendesk Support mobile app limitations


The Zendesk Support mobile app doesn't recognize allowed file
type settings. The app always accepts the following file
types:
bmp, csv, dib, doc, docx, gif, heic, heif, hif, icns,
ico, jpe, jpeg, jpg, key, numbers, odt, pages, pdf,
png, pps, ppsx, ppt, pptx, svg, svgz, text, tif,
tiff, txt, webp, xls, xls

To set allowed file types for attachments

In Admin Center, click
Objects and rules in the sidebar, then select Tickets > Settings.
Click Downloads and attachments to expand it.
Select an option for Allowed file types:

All file types: No restrictions.

Only recommended file types: Restrict
file attachments to a suggested list of commonly
used file types that are generally considered
safe. Zendesk recommends this option.

Only use these file types: Create a
custom list of allowed file types.


If you selected Only use these file types, list the
allowed file extensions, separated by commas, without
periods. Example: pdf, jpg, png
If you selected All file types or Only use these file
types, you must select the I agree to the
potential security risk involved by allowing
all/only these file types and extensions
checkbox to continue.
Click Save.




Attachment size limitations

Email and web form attachment limits are as follows:
The inbound email and web form attachment limit for a
single file is 50 MB. If a file attachment exceeds
50 MB, the ticket is created without the
attachment.
The outbound email attachment limit for a single file is
7 MB. When this limit is exceeded, Support will
process the attachment as a linked attachment
instead.
The total of all outbound email attachments cannot
exceed 10 MB. When these limits are exceeded,
Support will process the attachment as a linked
attachment instead.
The outbound email attachment limit for a single
linked file is 50 MB. Up to 500 files can
be attached. If you try to attach a file larger
than 50 MB, an error message will display and
inform you that the file is too large. The
attachment will not be attached to the ticket (as
either an email or linked attachment).

When you upload GIF files with a large number of frames,
the upload might fail with a timeout error. If this
occurs, try recreating the GIF file with fewer
frames.


For more information about attachment types, see About email attachments.
Attachments from earlier comments are included in email
notifications as linked attachments. If you add multiple attachments
to a reply, the attachments are prioritized based on the attachment
type and size. Inline attachments take precedence over appended
attachments when calculating size limits. Note that when inline
attachments are sent as links, they still appear as images in the
body of the email notification.
The scenarios below describe how this works.
Scenario 1
Two files are attached in the following order:
Email attachment A (3 MB)
Email attachment B (6 MB)


Behavior:
Files A and B are included as email attachments.


Scenario 2
Three files are attached in the following order:
Inline attachment A (5 MB)
Email attachment B (5 MB)
Email attachment C (4 MB)


Behavior:
Inline attachment A is sent as an email attachment.
Attachments B and C are included as file links, as they
push the total email attachment file size over 10
MB.


Scenario 3
Three files are attached in the following order:
Inline attachment A (5 MB)
Inline attachment B (6 MB)
Inline attachment C (4 MB)


Behavior:
Attachment A is included as an email attachment.
Attachment B is included as a file link, as it pushes
the total email attachment file size over 10 MB.
Attachment C is included as a real attachment, as it
brings the total email attachment file size to 9 MB.






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