How to Add 1-Click Calendar Links & RSVP Buttons in Brevo, Mailchimp, Klaviyo & HubSpot

Why Attaching .ICS Files to Marketing Emails Fails

When promoting a webinar, product launch, or live event via Brevo, Mailchimp, Klaviyo, or HubSpot, many marketers instinctively try to attach a static .ics file to their campaign.

Unfortunately, bulk email service providers (ESPs) and inbox filters treat attachments with suspicion:

• Most ESPs block attachments in bulk newsletters altogether.
• Spam filters penalize attachments, hurting your domain deliverability.
• Mobile friction: Tapping an .ics file inside Gmail on Android or Outlook on iOS often downloads a file into a hidden folder instead of opening the native calendar app.
• Zero analytics: Even if someone opens the attachment, you have no way of knowing how many subscribers actually saved the event.

The industry best practice is to use 1-click calendar links that route each subscriber to their specific calendar platform (Google Calendar, Outlook, Office 365, Apple Calendar, or Yahoo).

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The 3 Ways to Integrate CalLink into Your Email Platform

With CalLink, you can choose between three integration methods depending on your email design and campaign goal:

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Step-by-Step Setup by Email Platform

1. Brevo (formerly Sendinblue)

Brevo's drag-and-drop editor makes it effortless to use either the HTML snippet or native buttons:

1. Create your event in CalLink Events Studio and click Share / Embed.
2. Using the HTML Snippet:
   • In Brevo's email editor, drag the HTML block from the left sidebar into your email body.
   • Click the block to open the code panel on the left, and paste the CalLink Email HTML Snippet.
   • Brevo immediately renders the responsive buttons with inline table-safe CSS.
3. Using Native Brevo Buttons:
   • If you prefer Brevo's native button block, add a single button labeled "Save My Spot & Add to Calendar" and paste your public event URL (https://cal-link.com/e/...).

2. Mailchimp

In Mailchimp's New Builder or Classic Builder:

1. Drag a Code content block into your email layout right below your event announcement.
2. Delete the placeholder <div> and paste your CalLink HTML Snippet.
3. Pro Tip for Mailchimp Click Tracking: Mailchimp automatically wraps all https:// links for click tracking. Because CalLink's tracked links (https://cal-link.com/t/:id/apple) use standard https:// instead of raw webcal:// protocols, Mailchimp's link wrapper will never break Apple Calendar or Outlook downloads!

3. Klaviyo

Klaviyo is widely used by e-commerce and D2C brands for VIP product drops, live shopping sessions, and pop-up store launches:

1. In the Klaviyo template editor, drag a Text block or HTML block into your section.
2. Switch to the Source Code (</>) view and paste your CalLink HTML snippet.
3. Alternatively, use a Klaviyo Button block pointing to your branded CalLink page (/e/:id)—which automatically detects whether your shopper is on an iPhone (highlighting Apple Calendar) or Android (highlighting Google Calendar).

4. HubSpot Marketing Email

In HubSpot's Drag-and-Drop Email Editor:

1. Click + More in the left content tab and drag the HTML - Email module into your template.
2. Paste your CalLink HTML snippet into the code editor.
3. If you are running a B2B webinar and already captured the lead via a HubSpot form, use Method 2 in your automated confirmation email by linking directly to:
   • https://cal-link.com/t/YOUR_EVENT_ID/google (Google Calendar)
   • https://cal-link.com/t/YOUR_EVENT_ID/outlook (Outlook.com)
   • https://cal-link.com/t/YOUR_EVENT_ID/office365 (Microsoft 365 Corporate)
   • https://cal-link.com/t/YOUR_EVENT_ID/apple (Apple Calendar / Universal .ics)

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Why Using CalLink's Tracked Links (/t/:id/:service) Beats Static URLs

If you paste a raw Google Calendar URL (calendar.google.com/calendar/render?...) inside an email sent to 10,000 subscribers, what happens if your speaker shifts the webinar by 30 minutes or your Zoom link changes?

• With a static URL, everyone who clicks the old email saves the wrong time or broken Zoom link.
• With CalLink's dynamic tracked links (/t/:id/:service), you simply update the time or meeting URL once inside your CalLink dashboard. Even if a subscriber clicks an email you sent two weeks ago, CalLink dynamically generates the updated calendar invite on the fly!

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Ready to Test Your First Email Calendar Buttons?

Generate a ready-to-paste HTML snippet in 15 seconds with our Free Calendar Link Generator or explore our Email Calendar Links Feature Guide.