Create a virtual outfit try-on Telegram bot with async polling and Google Sheets

👗 Virtual Try-On Telegram Bot — AI Outfit Try-On via Telegram with Async Job Polling

Try on any outfit virtually - right inside Telegram. A user sends a person photo, then a garment photo (captioned garment), and the bot replies with an AI-generated try-on result image using a dedicated Virtual Try-On API. No app. No frontend. Just a Telegram chat.

🎯 Who Is This For?

• Fashion e-commerce brands wanting to offer a try-before-you-buy experience via a simple chat interface
• Telegram bot developers looking for a real-world async API polling pattern with state management
• AI product builders who want a plug-and-play virtual fitting room for their audience
• Boutiques & clothing stores wanting to let customers preview outfits before ordering

⚙️ What This Workflow Does

1. Receives a Telegram message and checks if it contains a photo
2. Person photo (sent without caption) → saves chat_id + file_id to Google Sheets as session state
3. Garment photo (sent with caption garment) → looks up the saved person photo, resolves both Telegram file URLs, downloads both images, and submits a try-on job to the API
4. Async polling loop → waits 15 seconds, checks job status, loops until completed or failed
5. Sends the result back to the user as a photo in Telegram, then cleans up the sheet row

🔑 Credentials & APIs Required

> 💡 Why Google Sheets for state? Each Telegram message triggers a separate workflow execution - there's no shared memory between runs. Google Sheets acts as a lightweight session store using chat_id as the unique key.

🛠️ Setup Instructions

Step 1 - Telegram Bot

1. Open Telegram and message @BotFather
2. Run /newbot, follow the prompts, copy your Bot Token
3. Paste the token into the ⚙️ Config node under botToken

Step 2 - Google Sheet

1. Create a new Google Sheet
2. Add a tab named exactly tryon-state
3. Add two column headers in row 1: chat_id and person_file_id
4. Copy the Sheet ID from the URL (docs.google.com/spreadsheets/d/**{THIS_PART}**/edit)
5. Paste it into the ⚙️ Config node under sheetId

Step 3 - Try-On API

1. Obtain your API key from your Virtual Try-On provider
2. Set tryonApiKey in the ⚙️ Config node
3. If your API base URL differs, also update tryonApiBase
4. Verify the API accepts POST /api/v1/tryon with multipart/form-data fields person_images and garment_images, and returns { jobId, statusUrl } - adjust the Submit Try-On Job and Check Job Status nodes if your provider's schema differs

Step 4 - n8n Credentials

• Assign your Telegram credential to all Telegram nodes (Trigger + all send nodes)
• Assign your Google Sheets OAuth2 credential to all Google Sheets nodes
• Activate the workflow - the Telegram Trigger only works when the workflow is active

🔄 How the Polling Loop Works

The Try-On API is asynchronous - submitting a job returns a jobId, not the result immediately. The workflow:

1. Submits the job → gets jobId
2. Waits 15 seconds
3. Calls the status endpoint: GET /api/v1/tryon/status/{jobId}
4. If status === "completed" → downloads and sends the result image
5. If status === "failed" → sends an error message to the user
6. Otherwise → loops back to the wait step

Typical total wait: 15–60 seconds depending on the API and queue load.

🎨 How to Customize

• Change the garment trigger keyword → Edit the caption check in Is Garment Photo? node from garment to anything you like (e.g. outfit, try, wear)
• Add a category/garment type input → Extend the caption parsing to accept values like top, dress, jacket and pass them as an extra field to your Try-On API if supported
• Use a different state store → Swap Google Sheets for Airtable, Supabase, or Redis if you have higher traffic needs; just replace the Save Person to Sheet and Lookup Person from Sheet nodes
• Add a paid/subscription gate → Before saving the person photo, check a users sheet or database to see if the chat_id has remaining credits
• Support multiple garments in one session → Instead of deleting the person row after each try-on, keep it for 24 hours so users can try multiple garments without re-uploading the person photo
• Add a result watermark → Insert an n8n Code node after HTTP Request (result download) to overlay your brand logo before sending

📋 Workflow Nodes Overview

⚠️ Notes & Gotchas

• Telegram file URLs expire - the workflow resolves and downloads images immediately; never store Telegram download URLs for later use
• The bot must be activated for the Telegram webhook to register - n8n does not receive messages while the workflow is inactive
• Google Sheets appendOrUpdate uses chat_id as the matching key, so a user can retake their person photo any time and it will overwrite the old entry
• Pinned test data is included in Submit Try-On Job and Merge State nodes for local testing — remove or disable these pins before going live

🔗 Useful Links

• Telegram BotFather — Create your bot
• n8n Telegram node docs
• n8n Google Sheets node docs
• n8n HTTP Request node docs
• n8n Wait node docs
• n8n Community Forum