GuidesReact UI, Node.js, Comments, Tutorials, Webhooks, Notifications

How to notify users about unread comments outside of your app

Liveblocks Comments allows you to build a commenting experience. With our webhooks and REST API, it’s possible to aggregate a list of unread comments, and use them to trigger notifications in Slack, Microsoft Teams, or any other external service with an API, using webhooks. Notifications can also be displayed in your app using useInboxNotifications and the InboxNotification component.

Want to send email notifications?

We have a specific guide on how to send email notifications of unread comments, which we recommend reading if you’re building emails.

What we’re building

In this guide we’ll be learning how to notify users about unread comments outside of your app, and more specifically, we’ll be looking at how to:

Trigger events based on unread comments using the NotificationEvent webhook event.
Fetch unread comments using the @liveblocks/node package.

Have a project ready

This guide assumes you already have a Liveblocks Comments project set up. If you don’t have one yet, you can get started with Comments, and come back after you’re set up.

What are inbox notifications?

Liveblocks uses the concept of inbox notifications, which differ to external notifications. Inbox notifications are displayed within in-app inboxes, group multiple activities together, and can change over time, like when a new comment is added to a thread.

External notifications, such as Slack, and Microsoft Teams, are different, and Liveblocks is set up to send them in a way that won’t overload your users with notifications. This means that Liveblocks will wait to trigger these notifications until a certain amount of time has passed, and will only trigger them if your users has not read the notification on the front-end, which we automatically keep track of. We then aggregate multiple unread comments into a single notification, so your users just get a single ping per thread.

Learn more about Notifications for Comments in the overview page.

Using webhooks

Liveblocks provides a number of webhooks that can send requests to your API endpoint when certain events occurs. One webhook we provide is the NotificationEvent webhook, which is triggered for each participating user in a thread, and can be used to send external notifications to your users.

The information it returns allows you to retrieve comments that have not yet been read by the user, making it possible to aggregate multiple unread comments into a single external notification. Let’s take a look at how to set this up.

Notification channels

You can send notifications via different channels, such as email, Slack, Microsoft Teams, and Web Push. In our dashboard, you can enable notifications on certain channels, and in this guide, we’ll be using the Slack channel. You must always enable the correct channel to ensure your NotificationEvent webhook events are triggered, and this guide will take you through setting it up.

Which notification channel?

All channels currently work the same way, apart from in-app, but we suggest selecting the service you’re setting up, such as Slack or Microsoft Teams, so it’s easy to tell which you’ve implemented.

Create an endpoint in your project

When a webhook event is triggered, it can send a POST request to the back end in your project. In this guide, we’ll be using a Next.js route handler (API endpoint) as an example, but other frameworks work similarly.

In order to use webhooks, we’ll need to retrieve the headers and body from the request. Here’s the basic endpoint we’ll be starting from:

export async function POST(request: Request) {  const body = await request.json();  const headers = request.headers;
  // Handle webhooks and notifications  // ...
  return new Response(null, { status: 200 });}

Create this endpoint in your project, and make it available on localhost at the following URL:

/api/liveblocks-notifications

Make a note of this endpoint URL, as you’ll be using it later.

Testing webhooks locally

Running webhooks locally can be difficult, but one way to do this is to use a tool such as localtunnel or ngrok which allow you to temporarily put your localhost server online.

If your project is running on localhost:3000, you can run the following command to generate a temporary URL that’s available while your localhost server is running:

Terminal

npx localtunnel --port 3000

localtunnel generates a base URL that can be placed into the Liveblocks webhooks dashboard for quick testing. To use this, take the full address of your webhook endpoint, and replace the domain in your localhost address with the generated URL.

# Take your local URLhttp://localhost:3000/api/liveblocks-notifications
# Replace localhost with the generated domain, then copy ithttps://my-localtunnel-url.loca.lt/api/liveblocks-notifications

You now have a URL that can be used in the webhooks dashboard.

Set up webhooks on the Liveblocks dashboard

To use webhooks, you need to pass your endpoint URL to the webhooks dashboard inside your Liveblocks project, and tell the webhook to trigger when a comment has been created.

Select your project
From the Liveblocks dashboard, navigate to the project you’d like to use with webhooks, or create a new project.
Go to the notifications dashboard
Click on the “Notifications” tab on the menu at the left.
Enable the thread notification type
Click on “Edit” at the top right, enable thread notifications on the Slack channel, and publish your changes.
Go to the webhooks dashboard
Click on the “Webhooks” tab on the menu at the left.
Create an endpoint
Click the “Add endpoint…” button on the webhooks dashboard to start setting up your webhook.
Add your endpoint URL
Enter the URL of the endpoint. In a production app this will be the real endpoint, but for now enter your localtunnel URL from earlier.
Enable notification webhook events
Check the “notification” event in the dialog to enable the correct webhooks events.
Get your webhook secret key
Click “Add endpoint” at the bottom, then find your “Secret key” on the next page, and copy it.
Webhooks dashboard is set up!
Notification webhooks are set up! Let’s go back to the code.

Verify the webhook request

The @liveblocks/node package provides you with a function that verifies whether the current request is a real webhook request from Liveblocks. You can set this up by setting up a WebhookHandler and running verifyRequest.

Make sure to add your webhook secret key from earlier—in a real project we’d recommend using an environment variable for this.

import { WebhookHandler } from "@liveblocks/node";
// Add your webhook secret key from a project's webhooks dashboardconst WEBHOOK_SECRET = "YOUR_WEBHOOK_SECRET_KEY";const webhookHandler = new WebhookHandler(WEBHOOK_SECRET);
export async function POST(request: Request) {  const body = await request.json();  const headers = request.headers;
  // Verify if this is a real webhook request  let event;  try {    event = webhookHandler.verifyRequest({      headers: headers,      rawBody: JSON.stringify(body),    });  } catch (err) {    console.error(err);    return new Response("Could not verify webhook call", { status: 400 });  }
  // Send notifications  // ...
  return new Response(null, { status: 200 });}

Check the event and notification permissions

After verifying the request, we can then check we’re receiving the correct type of event, on the correct channel. There are different notification events, and in this case we’d like to check for thread notification, as we’re specifically listening for new comments. We can do this using ThreadNotificationEvent, making sure to check for the slack channel.

import { WebhookHandler, isThreadNotificationEvent } from "@liveblocks/node";
// Add your webhook secret key from a project's webhooks dashboardconst WEBHOOK_SECRET = "YOUR_WEBHOOK_SECRET_KEY";const webhookHandler = new WebhookHandler(WEBHOOK_SECRET);
export async function POST(request: Request) {  const body = await request.json();  const headers = request.headers;
  // Verify if this is a real webhook request  let event;  try {    event = webhookHandler.verifyRequest({      headers: headers,      rawBody: JSON.stringify(body),    });  } catch (err) {    console.error(err);    return new Response("Could not verify webhook call", { status: 400 });  }
  // When an inbox notification has been created on the slack channel  if (isThreadNotificationEvent(event) && event.data.channel === "slack") {    const { roomId, threadId, inboxNotificationId, userId } = event.data;
    // Check if user has access to room    if (!(userId, roomId)) {      return new Response(null, { status: 200 });    }
    // Send notifications    // ...  }
  return new Response(null, { status: 200 });}

Note that we’re also checking if the user should receive a notification—Liveblocks doesn’t have knowledge of your permissions system on the back end, so it’s your responsibility to check if this user should have access to the room.

Get comment and thread data

Threads vs comments

Note that a thread is different to a comment—a thread is “top-level”, and each thread contains a list of comments. When you create a thread with useCreateThread, you also create the first comment in the thread.

The next step is to use the Liveblocks client from @liveblocks/node to retrieve the inbox notification, and the corresponding thread’s data. To do this we’ll need to add our project’s secret key from the dashboard to the Liveblocks client (not the webhook secret key we used earlier), before awaiting the following functions: getInboxNotification and getThread.

import {  Liveblocks,  WebhookHandler,  isThreadNotificationEvent,} from "@liveblocks/node";
// Add your webhook secret key from a project's webhooks dashboardconst WEBHOOK_SECRET = "YOUR_WEBHOOK_SECRET_KEY";const webhookHandler = new WebhookHandler(WEBHOOK_SECRET);
// Add your secret key from a project's API keys dashboardconst API_SECRET = "";const liveblocks = new Liveblocks({ secret: API_SECRET });
export async function POST(request: Request) {  const body = await request.json();  const headers = request.headers;
  // Verify if this is a real webhook request  let event;  try {    event = webhookHandler.verifyRequest({      headers: headers,      rawBody: JSON.stringify(body),    });  } catch (err) {    console.error(err);    return new Response("Could not verify webhook call", { status: 400 });  }
  // When an inbox notification has been created  if (isThreadNotificationEvent(event) && event.data.channel === "slack") {    const { roomId, threadId, inboxNotificationId, userId } = event.data;
    // Check if user has access to room    if (!(userId, roomId)) {      return new Response(null, { status: 200 });    }
    try {      // Get thread and notification      const [thread, inboxNotification] = await Promise.all([        liveblocks.getThread({ roomId, threadId }),        liveblocks.getInboxNotification({ inboxNotificationId, userId }),      ]);
      // Send external notifications      // ...    } catch (err) {      console.log(err);      return new Response("Could not fetch notification data", { status: 500 });    }  }
  return new Response(null, { status: 200 });}

Get the unread comments

The next step is to get each unread comment by comparing the readAt time in the inbox notification with the createAt time on each comment. We’re also filtering out each comment with no body, which represents a deleted comment.

import {  Liveblocks,  WebhookHandler,  isThreadNotificationEvent,} from "@liveblocks/node";
// Add your webhook secret key from a project's webhooks dashboardconst WEBHOOK_SECRET = "YOUR_WEBHOOK_SECRET_KEY";const webhookHandler = new WebhookHandler(WEBHOOK_SECRET);
// Add your secret key from a project's API keys dashboardconst API_SECRET = "";const liveblocks = new Liveblocks({ secret: API_SECRET });
export async function POST(request: Request) {  const body = await request.json();  const headers = request.headers;
  // Verify if this is a real webhook request  let event;  try {    event = webhookHandler.verifyRequest({      headers: headers,      rawBody: JSON.stringify(body),    });  } catch (err) {    console.error(err);    return new Response("Could not verify webhook call", { status: 400 });  }
  // When an inbox notification has been created  if (isThreadNotificationEvent(event) && event.data.channel === "slack") {    const { roomId, threadId, inboxNotificationId, userId } = event.data;
    // Check if user has access to room    if (!(userId, roomId)) {      return new Response(null, { status: 200 });    }
    try {      // Get thread and notification      const [thread, inboxNotification] = await Promise.all([        liveblocks.getThread({ roomId, threadId }),        liveblocks.getInboxNotification({ inboxNotificationId, userId }),      ]);
      // Get unread comments (and filter out deleted comments)      const readAt = inboxNotification.readAt;      const unreadComments = thread.comments        .filter((comment) => (readAt ? comment.createdAt > readAt : true))        .filter((comment) => comment.body !== undefined);
      // No unread comments, therefore no notification needed      if (unreadComments.length === 0) {        return new Response(null, { status: 200 });      }
      // Send notifications      // ...    } catch (err) {      console.log(err);      return new Response("Could not fetch notification data", { status: 500 });    }  }
  return new Response(null, { status: 200 });}

If there are no unread notifications, then we’re choosing not to send an email.

Generating comment text for the external notification

Now that we have the comment data, we have one more step before sending the notifications—formatting each comment’s text, found inside comment.body, and generating the text for our external notification.

By using await stringifyCommentBody, we can convert each comment into plain text, markdown, or HTML. In this code snippet, you can see we’re looping through each comment, and replacing comment.body with a markdown string.

import {  Liveblocks,  WebhookHandler,  isThreadNotificationEvent,  stringifyCommentBody,} from "@liveblocks/node";
// Add your webhook secret key from a project's webhooks dashboardconst WEBHOOK_SECRET = "YOUR_WEBHOOK_SECRET_KEY";const webhookHandler = new WebhookHandler(WEBHOOK_SECRET);
// Add your secret key from a project's API keys dashboardconst API_SECRET = "";const liveblocks = new Liveblocks({ secret: API_SECRET });
export async function POST(request: Request) {  const body = await request.json();  const headers = request.headers;
  // Verify if this is a real webhook request  let event;  try {    event = webhookHandler.verifyRequest({      headers: headers,      rawBody: JSON.stringify(body),    });  } catch (err) {    console.error(err);    return new Response("Could not verify webhook call", { status: 400 });  }
  // When an inbox notification has been created  if (event.type === "notification") {    const { roomId, threadId, inboxNotificationId, userId } = event.data;
    // Check if user has access to room    if (!(userId, roomId)) {      return new Response(null, { status: 200 });    }
    try {      // Get thread and notification      const [thread, inboxNotification] = await Promise.all([        liveblocks.getThread({ roomId, threadId }),        liveblocks.getInboxNotification({ inboxNotificationId, userId }),      ]);
      // Get unread comments (and filter out deleted comments)      const readAt = inboxNotification.readAt;      const unreadComments = thread.comments        .filter((comment) => (readAt ? comment.createdAt > readAt : true))        .filter((comment) => comment.body !== undefined);
      // No unread comments, therefore notification needed      if (unreadComments.length === 0) {        return new Response(null, { status: 200 });      }
      // Convert comments to markdown and return { body: "**...**", ...comment } format      const textComments = await Promise.all(        unreadComments.map(async (comment) => ({          body: await stringifyCommentBody(comment.body, {            format: "markdown",          }),          ...comment,        }))      );
      // Create final markdown for notification      let markdown = "# New notifications";      for (const comment of textComments) {        markdown += `          **Comment by ${comment.userId} at ${comment.createdAt}**:          ${comment.body}        `;      }      markdown += `        [Go to thread](https://my-company.com/room/${roomId}#${threadId})      `;
      // Send notifications      // ...    } catch (err) {      console.log(err);      return new Response("Could not fetch notification data", { status: 500 });    }  }
  return new Response(null, { status: 200 });}

This snippet outputs simple formatting, for example it renders a user IDs (e.g. @jory.quispe) instead of a names (e.g. @Jory Quispe), but you can create more complex formatting easily by using more complex stringifyCommentBody options.

Send external notifications

Now that the comment’s body has been formatted, we can send the external notifications. In this example, we’re sending our markdown to an incoming webhook in Slack.

import {  Liveblocks,  WebhookHandler,  isThreadNotificationEvent,  stringifyCommentBody,} from "@liveblocks/node";
// Add your webhook secret key from a project's webhooks dashboardconst WEBHOOK_SECRET = "YOUR_WEBHOOK_SECRET_KEY";const webhookHandler = new WebhookHandler(WEBHOOK_SECRET);
// Add your secret key from a project's API keys dashboardconst API_SECRET = "";const liveblocks = new Liveblocks({ secret: API_SECRET });
export async function POST(request: Request) {  const body = await request.json();  const headers = request.headers;
  // Verify if this is a real webhook request  let event;  try {    event = webhookHandler.verifyRequest({      headers: headers,      rawBody: JSON.stringify(body),    });  } catch (err) {    console.error(err);    return new Response("Could not verify webhook call", { status: 400 });  }
  // When an inbox notification has been created  if (event.type === "notification") {    const { roomId, threadId, inboxNotificationId, userId } = event.data;
    // Check if user has access to room    if (!(userId, roomId)) {      return new Response(null, { status: 200 });    }
    try {      // Get thread and notification      const [thread, inboxNotification] = await Promise.all([        liveblocks.getThread({ roomId, threadId }),        liveblocks.getInboxNotification({ inboxNotificationId, userId }),      ]);
      // Get unread comments (and filter out deleted comments)      const readAt = inboxNotification.readAt;      const unreadComments = thread.comments        .filter((comment) => (readAt ? comment.createdAt > readAt : true))        .filter((comment) => comment.body !== undefined);
      // No unread comments, therefore notification needed      if (unreadComments.length === 0) {        return new Response(null, { status: 200 });      }
      // Convert comments to markdown and return { body: "**...**", ...comment } format      const textComments = await Promise.all(        unreadComments.map(async (comment) => ({          body: await stringifyCommentBody(comment.body, {            format: "markdown",          }),          ...comment,        }))      );
      // Create final markdown for notification      let markdown = "# New notifications";      for (const comment of textComments) {        markdown += `          **Comment by ${comment.userId} at ${comment.createdAt}**:          ${comment.body}        `;      }      markdown += `        [Go to thread](https://my-company.com/room/${roomId}#${threadId})      `;
      // Send your external notifications, e.g. to Slack      await fetch(        "https://hooks.slack.com/services/T00000000/B00000000/XXXXXXXXXXXXXXXXXXXXXXXX",        {          method: "POST",          headers: { "Content-Type": "application/json" },          body: JSON.stringify({            text: markdown,            username: `@${userId}`,          }),        }      );    } catch (err) {      console.log(err);      return new Response("Could not fetch notification data", { status: 500 });    }  }
  return new Response(null, { status: 200 });}

We’ve now successfully sent an external notification to a user!

Allow users to toggle notifications

Using Liveblocks hooks and methods, it’s possible to create a notifications settings interface, allowing end users to choose which notifications they’d like to receive, and on which channels, saving their preferences.

Learn more in our guide on creating a notification settings panel.

Recap

Great, we’re successfully sending external notifications to users when comments are left unread! In this guide we’ve learned:

How to use webhooks and the NotificationEvent.
How to use the @liveblocks/node package to fetch and render unread thread data.
How to hook it up to an external service, such as Slack.

How to notify users about unread comments outside of your app

What we’re building

What are inbox notifications?

Using webhooks

Notification channels

Create an endpoint in your project

Testing webhooks locally

Set up webhooks on the Liveblocks dashboard

Select your project

Go to the notifications dashboard

Enable the thread notification type

Go to the webhooks dashboard

Create an endpoint

Add your endpoint URL

Enable notification webhook events

Get your webhook secret key

Webhooks dashboard is set up!

Verify the webhook request

Check the event and notification permissions

Get comment and thread data

Get the unread comments

Generating comment text for the external notification

Send external notifications

Allow users to toggle notifications

Recap

Migrating to Liveblocks Notifications

Can I use my own database with Yjs?

How to notify users about unread comments outside of your app

Select your project

Go to the notifications dashboard

Enable the thread notification type

Go to the webhooks dashboard

Create an endpoint

Add your endpoint URL

Enable notification webhook events

Get your webhook secret key

Webhooks dashboard is set up!

Related guides

Migrating to Liveblocks Notifications

Can I use my own database with Yjs?