Notification Bar

The Notification Bar site app displays a customizable banner at the top of your website. Use it to announce product updates, promotions, events, or important notices to visitors.

How it works

Once installed and configured, the notification bar injects a banner at the top of every page where posthog-js is loaded. It renders inside a shadow DOM element so its styles don't conflict with your site.

The banner:

• Displays your custom message with support for HTML, including links and bold text
• Can be styled with custom background, text, and link colors
• Supports sticky (fixed at top of viewport) or top of page (scrolls with content) positioning
• Can be dismissed by clicking anywhere on the bar (outside of links)
• Optionally remembers when a user dismisses it using localStorage, so it won't reappear until you change the message
• Can be restricted to specific domains using a comma-separated list

Use cases

• Product launches – Announce new features or product releases
• Promotions – Highlight sales, discounts, or limited-time offers
• Events – Promote upcoming webinars, conferences, or community events
• Status updates – Communicate maintenance windows or known issues
• Navigation – Direct users to important pages like documentation or signup

Requirements

The Notification Bar requires either PostHog Cloud, or a self-hosted PostHog instance running version 1.41.0 or later.

You also need to opt in to the site apps beta by setting opt_in_site_apps: true in your posthog-js initialization.

Installation

1. Configure your posthog-js initialization to include opt_in_site_apps: true:

   JavaScript

   PostHog AI

   posthog.init("<ph_project_token>", {
     api_host: "https://us.i.posthog.com",
     opt_in_site_apps: true,
   });

2. In PostHog, go to Data > Pipeline > Destinations

3. Search for Notification Bar and click + Create

4. Configure the bar with your message, colors, and positioning

5. Click Save and enable the destination

FAQ

Is the source code for this app available?

PostHog is open-source and so are all apps on the platform. The source code for the Notification Bar is available on GitHub.

Who created this app?

We'd like to thank PostHog team member Marius Andra for creating this app. Thanks, Marius!

Who maintains this app?

This app is maintained by PostHog. If you have issues with the app not functioning as intended, have feedback, or your question isn't answered above, please let us know or ask via our community forum.