n8n Instagram Auto Reply Workflow: Graph API + Gemini DMs

Automatically reply to Instagram comments (and optional DMs) using n8n + Gemini

This n8n Instagram Auto Reply Workflow listens for Instagram webhook events, generates concise replies with Google Gemini, posts them via the Facebook Graph API, and logs everything to Slack and Google Sheets.

What this workflow does

• Receives Meta webhook events for Instagram and responds to the Meta verification challenge during subscription setup.
• Acknowledges incoming events and ignores events created by your own Instagram account to prevent reply loops.
• For comment events: fetches the related Instagram media caption using the Facebook Graph API, then uses Google Gemini to draft a one-line public reply (or the workflow result no_answer when no response is needed).
• When a reply is needed, it waits a random 3–5 minutes to space out responses, then posts the reply back to the original comment via the Facebook Graph API.
• Notifies a Slack channel and updates a “last run” timestamp in Google Sheets.
• If the generated public reply includes the keyword “DM”, Gemini drafts a private DM, and the workflow sends it via the Facebook Graph API and logs the DM content to Slack.
• For story mention events, it sends a notification to a dedicated Slack channel.

Use cases

• Turn Instagram comment engagement into immediate, on-brand responses while keeping posts natural with a 3–5 minute delay.
• Automatically trigger a private DM when your public reply indicates “DM”.
• Give your team visibility with Slack alerts and operational tracking via Google Sheets.

Technical details

• Meta Webhooks (Instagram subscription verification + event intake)
• Nodes/logic: webhook, if, code, wait, slack, google sheets
• Facebook Graph API for reading Instagram captions, posting comment replies, and sending messages (Graph API permissions required)
• Google Gemini for drafting public replies and optional DM content