n8n LINE to AI Banner Generator: Gemini + Nano Banana Pro

Turn simple LINE messages into high-quality AI banner images (Gemini + Nano Banana Pro)

This n8n workflow generates text-rich advertising banners from a LINE banner concept—using Google Gemini to craft marketing-ready prompts and Nano Banana Pro (via Kie.ai API) to produce images with superior text rendering. It then uploads the result to an AWS S3 bucket and sends the final banner back to the user on LINE.

What this workflow does

• 1) Input via LINE: A user sends a banner concept message (e.g., brand name + vibe) through a LINE Official Account.
• 2) Prompt engineering with Google Gemini: Gemini transforms the concept into a detailed request, including guidance for lighting, composition, and Japanese catch-copy placement.
• 3) Async image generation (Nano Banana Pro / Kie.ai API): The workflow submits a generation job, then waits and polls until the image is ready—so you get high-quality results instead of timeouts.
• 4) Hosting on AWS S3: The generated image is downloaded and uploaded to a public AWS S3 bucket.
• 5) Delivery back to LINE: The workflow pushes the completed banner image to the user on LINE.

Use cases

• Marketing A/B testing: Quickly produce multiple banner variations from short LINE inputs.
• Japanese market advertising: Generate banner creatives with more accurate, readable text placement using Nano Banana Pro.
• Developer reference: Learn an end-to-end Async API polling pattern in n8n using Kie.ai job completion.

Technical details

• n8n workflow type: n8n automation workflow for banner generation (Gemini + Nano Banana Pro).
• Nodes/tech used: Code, Wait, HTTP Request, Webhook, AWS S3, plus supporting notes (Sticky Note).
• Required credentials: Kie.ai API Key for Nano Banana Pro, Google Gemini API Key, AWS S3 public access, and LINE Messaging API.
• Authorization: Configure Header Auth for Kie.ai nodes (Authorization: Bearer ...).