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

Detect keywords in comments and trigger DM flows instantly.

Automated conversations that convert commenters into leads.

Common Questions About Comment-to-DM Automation

What is comment-to-DM automation?

└Comment-to-DM automation automatically sends a private DM to anyone who comments a specific keyword on your Instagram or Facebook post. It's commonly used for lead magnets, discount codes, and giveaways. Zernio lets you set this up with one API call.

Does comment-to-DM work on Instagram Reels?

└Yes. Instagram Reels are treated as posts by Meta's Graph API. The same comment webhooks and DM endpoints work for Reels, feed posts, carousels, and Stories.

How is Zernio different from ManyChat for comment-to-DM?

└ManyChat is a no-code tool for end users. Zernio's API is a ManyChat alternative that lets developers embed comment-to-DM as a feature inside their own applications with full programmatic control.

How fast are DMs sent after a comment?

└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.

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

└Yes, when using Meta's official API (not browser automation or unofficial tools). Zernio is an official 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.

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.

How much does comment-to-DM automation cost?

└Zernio's comment automation is bundled with every connected account (no 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 predictable usage-based pricing (no per-message surprises).

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