Uploading and managing calendar files (ICS)

Uploading ICS files to your media library and linking them in your emails allows recipients to add your event details to their calendar with one click. This article explains how to upload, manage, and use ICS files in your campaigns.

What are ICS files and why are they useful?

ICS files are calendar files that contain event information such as date, time, location, and description. When someone clicks on a link to an ICS file, their calendar app automatically opens with all details already filled in.

Why this is important: People who have events in their calendar receive automatic reminders from their calendar app. This significantly reduces the chance of no-shows compared to simply mentioning a date in your email.

What do you need to get started?

Before you start, make sure you have:

• Access to the Email builder
• A valid ICS file of your event
• Sufficient storage space in your media library

Uploading ICS files to your media library

Step 1: Open your media library

Navigate to your media library where you upload all other images and files via Account → Settings → Media library.

Step 2: Upload your ICS file

1. Click the button to upload a new file
2. Select your ICS file from your computer
3. The system automatically checks whether the file has a valid structure

Step 3: Recognize your ICS file in the library

After uploading, your ICS file appears in the media library with a clear calendar icon. The file type is displayed as "Calendar" or "ICS". Optionally filter on 'files' so you can easily find it back.

Adding an ICS file to your email

Now that your ICS file is in the media library, you can link it in your campaigns.

Step 1: Create your message in the Email Builder

Open the Email Builder and start composing your message.

Step 2: Add an element for your calendar file

You can add a "File" link to:

• CTA (buttons)
• Text (for example "Add to calendar")
• Images

Drag the desired element to your message.

Step 3: Add a link and select "File" as link type

1. Click on the element to which you want to add the link
2. Click on "Add link" in the configuration panel on the right side
3. Select "File" as link type
4. Click on the "Media" button to open your Media library

Step 4: Choose your ICS file

1. Select the correct ICS file from the list and click on "Insert file".
2. You will see the filename as confirmation of your choice.

Organizing and managing your calendar files

Searching and filtering files

For ICS files, and all other media files, you can:

• Search by name
• Filter by type "Documents"
• Organize in folders

Renaming or deleting files

You can rename or delete ICS files like any other file in your media library:

1. Click on the file you want to edit
2. Choose "Rename" or "Delete"
3. Confirm your action

Pro tips and best practices

Make your calendar links clearly recognizable

People must immediately understand what happens when they click. Therefore use buttons or links with text such as:

• 📅 Add to calendar
• Save this date
• Put in your calendar

Test your ICS file before uploading it

Open your ICS file in your own calendar app before uploading it to Flexmail.

This way you check whether:

• The date and time are correct
• The timezone is correct
• The location and description are properly filled in

Use clear filenames

Give your ICS files logical names like "Webinar_ProductLaunch_Jan2026.ics" instead of "event1.ics". This makes it easier to choose the right file when you manage multiple events.

Track engagement

Although you cannot directly see who has added the event to their calendar, you can track the engagement in your campaign reports. A high click rate on your calendar link is a good indicator of engagement.

Avoiding common mistakes

My ICS file shows an incorrect icon in the media library

What is going on: The icon is determined based on the file type. Only a .ics file will display a calendar icon.

Solution: Rename the file so that it has the .ics extension before uploading. If the file has already been uploaded, delete it and upload again with the correct extension.

The file does not upload with the error message "Unsupported file type"

What is happening: your calendar file may not have the correct format. We only support calendar files with the extension *.ics .

Solution: Always choose the ICS file type when saving, exporting, or generating your calendar files.

The file does not upload with the error message "upload failed"

What is happening: Your ICS file is possibly missing one or more required elements in the structure.

Solution: Open your ICS file in a text editor and check whether it contains the following lines:

• BEGIN:VCALENDAR       
• VERSION:2.0       
• BEGIN:VEVENT       
• END:VEVENT       
• END:VCALENDAR       

If any of these are missing, you must regenerate the ICS file with your calendar app or an online ICS generator.

The calendar link downloads the file but does not open a calendar app

What is happening: This behavior depends on the email client and device of the recipient.

What you should know: With some webmail clients (such as Gmail in a browser) the ICS file is downloaded, after which the user must import it manually. This is normal behavior and not a problem with Flexmail.

The event appears in the wrong timezone in recipients' calendars

What is happening: The timezone settings in your ICS file are not correctly configured.

Solution: This is not a Flexmail problem but a configuration of the ICS file itself. Regenerate the ICS file with the correct timezone information. Test the file outside Flexmail by emailing it to yourself and checking whether it opens correctly.

What you can do now

Now that you know how to upload and manage ICS files, you can:

Get started immediately:

1. Create an ICS file for your next event

2. Upload it to your media library

3. Add an "Add to calendar" button to your next campaign

Explore further:

• View the manual about the new Email Builder for more advanced link options
• Learn how to create effective call-to-action buttons
• Discover how to organize your media library efficiently

Apply best practice:

Test your first calendar link by sending a test campaign to yourself. Click on the link and check whether the event is added correctly to your calendar. Only then send to your complete target audience.

Frequently asked questions

Do ICS files count towards my storage limit?

Yes, ICS files count towards your standard storage limit in the media library, just like images and PDF files.

Can I change event details after I have sent the email?

The ICS file in the sent email is static. If event details change, you must upload a new ICS file and send an update email to your recipients. For example, mention "Updated event details" in the subject line.

Does this work with all calendar apps?

Yes, ICS is an industry-standard format that works with all major calendar applications such as Outlook, Google Calendar, Apple Calendar, Yahoo Calendar and most others.

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