Opening Problem Statement
Meet Sarah, an Instagram influencer with over 50,000 followers. Every day, her inbox floods with hundreds of questions and comments from her subscribers. Sarah spends more than three hours daily just replying to these messages — time she could use to create new content or engage with followers more meaningfully. Unfortunately, manually answering each message leads to occasional delayed responses and inconsistent tone, which can frustrate her audience and reduce engagement.
Sarah needs a smart solution to automatically manage incoming Instagram messages, responding quickly in her unique style without spending extra hours at her keyboard. This is where automation with n8n and ChatGPT comes in.
What This Automation Does
This workflow automates Sarah’s Instagram messaging via ManyChat integration and ChatGPT’s AI capabilities. When a subscriber sends a message to Sarah’s Instagram, ManyChat captures it and forwards it to n8n through a webhook. n8n then uses ChatGPT to generate a personalized response that mimics Sarah’s writing style based on her prior posts. The response is sent back through ManyChat to the subscriber’s Instagram.
- Receives Instagram messages via ManyChat webhook
- Sets a custom system prompt to maintain influencer’s unique style
- Utilizes ChatGPT model for AI-generated responses
- Maintains conversation context with a memory buffer for coherent replies
- Automatically sends the AI-generated response back to Instagram through ManyChat
- Reduces manual response time by over 3 hours daily, ensures consistency and timely communication
Prerequisites ⚙️
- n8n account (cloud or self-hosted) ⚙️
- ManyChat account linked to Instagram 💬
- OpenAI API key for ChatGPT access 🔑
- Webhook URL configuration in ManyChat for forwarding messages to n8n 🔌
Step-by-Step Guide
1. Set Up the ManyChat Webhook to n8n
Navigate to the Getting message from Instagram node (Webhook). Copy the webhook URL generated by n8n.
In ManyChat, create a custom action that triggers when a subscriber sends a message on Instagram. Paste the webhook URL here to forward messages to n8n automatically.
Expected result: Messages from Instagram start arriving in n8n’s webhook node.
Common mistake: Forgetting to set the webhook HTTP method to POST in ManyChat.
2. Define System Prompt for AI Responses
Open the Set your system promt for AI node (Set node). Edit the “prompt” variable to personalize the AI’s tone and style. In this example, the prompt is set to behave as an Instagram influencer replying simply and consistently.
Example prompt:Persona: You are a instagram influencer.
Context: You receive a messages from your subscribers
Task: Answer questions in your writing style and patterns according to your previous posts text. Use your post only for style and patterns reference.
Style rules:
simple answers
Expected result: AI generates replies matching the influencer’s voice.
Common mistake: Leaving placeholder or generic prompts that make AI sound robotic or off-topic.
3. Configure AI Memory for Contextual Replies
Locate the Local n8n memory node (Memory Buffer Window). This node keeps the last 20 messages in the conversation for context, allowing more natural AI replies.
Expected result: AI understands previous messages to maintain relevant and coherent responses.
Common mistake: Setting the context window length too low can lead to disjointed answers.
4. Choose and Connect the ChatGPT Model
Open the ChatGPT model node. This node uses the OpenAI API to process the input and generate responses. Ensure your OpenAI credential is properly attached.
Expected result: AI generates responses based on the system prompt and message context.
Common mistake: Missing or invalid OpenAI API credentials will cause failures.
5. Set Up the AI Agent Node to Manage Incoming Text
The AI Agent node orchestrates the prompt, chat input, chat history, and calls the ChatGPT model. It uses the system prompt, the subscriber’s message, and conversation memory to produce the best response.
Expected result: AI Agent outputs a suitable reply ready to send.
Common mistake: Wrong reference to session ID or message text variables might cause empty or incorrect output.
6. Respond Back to Instagram
The Send respond node responds back to the webhook request, passing the AI-generated text to ManyChat, which then delivers it to the subscriber’s Instagram inbox.
Expected result: Subscribers receive prompt, personalized replies automatically.
Common mistake: Misconfigured response node might cause ManyChat to receive empty or malformed messages.
Customizations ✏️
- Adjust AI Style: In the “Set your system promt for AI” node, modify the “prompt” variable to match different influencer personas or formal/informal tones.
- Change Memory Length: Increase or decrease the “contextWindowLength” in the “Local n8n memory” node to control how many previous messages the AI remembers.
- Switch ChatGPT Models: In the “ChatGPT model” node, select a different OpenAI language model (e.g., GPT-4) for more advanced responses.
- Modify Webhook Path: Change the webhook path in the “Getting message from Instagram” node to customize the URL for different campaigns.
- Add Additional Logging: Insert a “Set” or “Function” node before or after AI nodes to log conversations for analysis or debugging.
Troubleshooting 🔧
Problem: “No response from ChatGPT”
Cause: OpenAI API key invalid or rate limit exceeded.
Solution: Verify API credentials in “ChatGPT model” node. Check OpenAI usage dashboard. Renew key or upgrade limits if needed.
Problem: “Webhook receives no data”
Cause: ManyChat webhook not set correctly or HTTP method mismatch.
Solution: Ensure ManyChat custom action points to n8n webhook URL with POST method. Send test message from Instagram subscriber.
Problem: “AI replies are irrelevant or generic”
Cause: Weak or generic system prompt in “Set your system promt for AI” node.
Solution: Refine prompt with clearer persona description and style rules for more accurate, personalized responses.
Pre-Production Checklist ✅
- Test webhook by sending messages from Instagram subscriber connected to ManyChat.
- Check system prompt clarity in the “Set your system promt for AI” node.
- Verify OpenAI API key and model selection.
- Ensure the local memory node is correctly feeding context to AI Agent.
- Confirm response node successfully sends replies back to ManyChat.
- Backup the n8n workflow version before deployment.
Deployment Guide
Activate the workflow in n8n by toggling the active status. Monitor execution through the n8n UI to ensure messages are processed correctly. If errors occur, review logs and adjust nodes as necessary. Regularly check your OpenAI usage to avoid interruptions.
FAQs
Can I use other AI models instead of ChatGPT?
Yes, n8n supports different AI models. This workflow uses OpenAI’s GPT, but you can configure other providers that integrate with n8n.
Does this automation consume OpenAI API credits?
Yes, every message processed by ChatGPT consumes API usage. Monitor your OpenAI account to manage costs.
Is this setup secure for handling private messages?
All communication between ManyChat, n8n, and OpenAI uses secure HTTPS endpoints. However, handle API keys carefully and avoid exposing sensitive data in logs.
Conclusion
By following this guide, you created an automated Instagram messaging workflow that uses ManyChat, n8n, and ChatGPT to reply intelligently and quickly to subscriber messages. Sarah now saves over three hours daily and keeps a consistent personal touch in every interaction. Next, you can expand this by adding analytics for message sentiment or integrating other social platforms to manage all your social media chats efficiently.