Comment to DM Automation API: Build Instagram Auto-DMs in Code

How It Works

1. 1.
   Create an automation via API

   POST to /api/v1/comment-automations with your account ID, keywords, DM message, and optional public reply. One API call, done in seconds.
2. 2.
   User comments on your post

   When someone comments a matching keyword on any of your posts or Reels, Zernio's webhook listener detects it in real-time via Meta's Graph API.
3. 3.
   DM sent automatically

   Zernio sends a private DM to the commenter within 1-3 seconds, optionally posts a public reply, creates a contact in your CRM, and logs the event.

Why Developers Choose API Over No-Code

Code Examples

const response = await fetch('https://zernio.com/api/v1/comment-automations', {
  method: 'POST',
  headers: {
    'Authorization': 'Bearer YOUR_API_KEY',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    accountId: 'your-instagram-account-id',
    name: 'Free Guide Giveaway',
    keywords: ['guide', 'free', 'link'],
    matchMode: 'contains',
    dmMessage: 'Thanks for your interest! Here is your free guide: https://example.com/guide',
    commentReply: 'Check your DMs!'
  })
});

const automation = await response.json();
console.log(automation.id); // Use this ID to update, pause, or view logs

const response = await fetch('https://zernio.com/api/v1/comment-automations', {
  headers: { 'Authorization': 'Bearer YOUR_API_KEY' }
});

const { data } = await response.json();
data.forEach(automation => {
  console.log(automation.name);
  console.log('  Triggered:', automation.stats.triggered);
  console.log('  DMs sent:', automation.stats.dmsSent);
  console.log('  Unique contacts:', automation.stats.uniqueContacts);
});

// 1. Webhook handler for incoming comments
app.post('/webhook/instagram', (req, res) => {
  const { entry } = req.body;
  for (const page of entry) {
    for (const change of page.changes) {
      if (change.field === 'comments') {
        const comment = change.value;
        const text = comment.text.toLowerCase();

        // 2. Keyword matching
        const keywords = ['guide', 'free', 'link'];
        const matches = keywords.some(kw => text.includes(kw));

        if (matches) {
          // 3. Send DM via Private Reply API
          await fetch(
            `https://graph.facebook.com/v21.0/${PAGE_ID}/messages`,
            {
              method: 'POST',
              headers: { 'Content-Type': 'application/json' },
              body: JSON.stringify({
                recipient: { comment_id: comment.id },
                message: { text: 'Here is your free guide: https://...' }
              })
            }
          );
        }
      }
    }
  }
  res.sendStatus(200);
});

// With Zernio: one API call replaces all of the above

Supported Platforms

Comment-to-DM automation works on Instagram and Facebook via Meta's Graph API. Both platforms use the same webhook flow and Private Reply endpoint.

See it in action

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Common Questions About Comment-to-DM Automation

What is comment-to-DM automation?

└Comment-to-DM is a social media automation that sends a Direct Message to users who comment on your posts. When someone comments a specific keyword (e.g. 'LINK' or 'FREE'), the automation instantly delivers a pre-written DM containing a link, discount code, or lead magnet. DMs have 90%+ open rates compared to 20% for email, making this one of the highest-converting lead capture methods on Instagram.

Is comment-to-DM automation safe for my Instagram account?

└Yes, when using Meta's official API (not browser automation or unofficial tools). Zernio and ManyChat are both Meta Business Partners using the official Graph API. The Private Reply API is Meta's approved method for sending DMs in response to comments. Unofficial tools that scrape or automate the browser can get your account restricted.

Do I need a Business account for comment-to-DM?

└Yes. Instagram requires a Business or Creator account connected to a Facebook Page to use the Messaging API for private replies. Personal accounts cannot use the comment-to-DM API.

How fast are automated DMs sent?

└With webhook-based systems like Zernio, DMs are sent within 1-3 seconds of the comment being posted. Zernio subscribes to Meta's real-time webhooks, so there is no polling delay.

Does comment-to-DM work for Instagram Reels?

└Yes. Instagram Reels are treated as posts by Meta's API, so the same comment webhook and Private Reply endpoints work for Reel comments, feed post comments, and carousel comments.

Can I trigger on any comment or just specific keywords?

└Both. Zernio supports keyword triggers with exact or contains matching. You can also leave keywords empty to trigger the automation on any comment, regardless of what the user types.

What is the difference between comment-to-DM and auto-reply to DMs?

└Comment-to-DM triggers when someone comments on a post and sends them a DM. Auto-reply to DMs triggers when someone sends you a direct message and responds automatically. They are different automation types. Zernio supports both via separate API endpoints.

Why use an API instead of ManyChat or Inro?

└ManyChat and Inro are no-code tools for creators and marketers. They have no public API, so you cannot build comment-to-DM into your own SaaS product, white-label it, or control it programmatically. Zernio's API lets developers embed comment-to-DM as a feature inside their own applications with full programmatic control.

Does comment-to-DM work on Facebook too?

└Yes. Zernio supports comment-to-DM on both Instagram and Facebook. Both use Meta's Graph API with the same Private Reply endpoint. Most competitors only support Instagram.

How much does comment-to-DM automation cost?

└Zernio's comment automation is included with the Inbox add-on. No per-contact billing, no per-message fees. ManyChat charges per contact ($0.025/contact overage) which can get expensive with viral posts. Zernio charges per social account with flat, predictable pricing.

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