Auto-Generate and Post Instagram Reels with n8n: Veo3 + OpenAI + Blotato

Chat input → AI video prompt generation → Veo3 9:16 short video generation → poll for result → AI caption → log to Google Sheets → auto-publish to Instagram via Blotato

Who

Content creators, brand operators, and small teams looking to batch-generate and auto-publish Instagram Reels without manual shooting or editing

You get

Send one chat message to automatically complete the full pipeline from video generation to Instagram publishing, including prompt generation, video rendering, caption writing, spreadsheet logging, and auto-posting

You need

n8n · chat-trigger · openai · http-request · google-sheets

Steps

1. Configure Chat Trigger

   Add the 'When chat message received' node as the workflow entry point. No extra parameters needed; keep defaults to trigger via chat interface or Telegram. Example message: "Make a reel for a luxury minimalist candle brand using calm aesthetics."

2. Configure AI Video Prompt Agent

   Add an OpenAI node (AI Video Prompt Agent), model set to gpt-4. The system prompt converts user input into a video generation prompt suitable for the Veo3/Seedance API. Output must be under 100 words, pure prompt text only, no extra explanation or formatting.

   Execution prompt · Source text。OpenAI node AI Video Prompt Agent system message field

   Copy prompt

   You are a creative video prompt generator for short-form reels (e.g., Instagram, TikTok). Based on:
   
   The chat input of the user
   
   Your task is to craft an elaborate, visually descriptive video generation prompt suitable for input into the Seedance/Veo3 API.
   
   🛑 Do not include any extra explanation, formatting, or commentary. Your entire output must be the exact prompt to pass into the video generator.
   
   The prompt should:
   – Be under 100 words
   – Describe the visual elements, tone, and motion clearly
   – Reflect the thematic visual in a coherent manner
   
   Example of your expected output format:
   
   “A close-up slow-motion shot of a glass perfume bottle as morning sunlight filters through mist. The background shows soft-focus wildflowers, matching the theme of natural beauty and calm. Overlay text: ‘Nature’s Elegance. Reinvented.’ Trend-inspired styling based on the ‘quiet luxury’ aesthetic. For Instagram.”

3. Configure Veo3 Video Generation and Result Polling

   Add and connect the following nodes in sequence: 1. HTTP Request node (Veo3 Video Generator): POST to https://api.wavespeed.ai/api/v3/google/veo3-fast, body includes aspect_ratio=9:16, duration=8, enable_prompt_expansion=true, generate_audio=true, prompt from previous AI output. 2. Wait node: 30-second fixed delay. 3. HTTP Request node (HTTP Get Request): GET https://api.wavespeed.ai/api/v3/predictions/{{ $json.data.id }}/result, using httpHeaderAuth credential. 4. If node: check if data.status equals processing. If true, route to 'Wait 30 Secs' node (another 30-second delay) then loop back to HTTP Get Request; if false, proceed to next step. Note: Both Wait nodes use a fixed 30-second delay.

4. Configure Caption Agent

   Add an OpenAI node (Caption Agent), model set to chatgpt-4o-latest. The system prompt specifies an Instagram caption copywriter with playful and impactful style. Input references the video prompt from AI Video Prompt Agent; output is the accompanying caption.

   Execution prompt · Source text。OpenAI node Caption Agent system message field

   Copy prompt

   You're an Instagram Caption copywriter. You'll receive a set of video prompt message that is used for generating an Instagram short reel video. Your job is to write an effective accompanying caption. Language style should be playful and impactful.

5. Log to Google Sheets

   Add a Google Sheets node (Google Sheet Ready To Post), operation set to Append. Configure documentId and sheetName to point to your tracking spreadsheet. Write fields: Video Description / Prompt (from AI Video Prompt Agent), Video URL (google drive) (from If node data.outputs[0]), Caption (from Caption Agent), Status set to 'Ready to Post'. Column names must match the node schema.

6. Upload Media and Publish to Instagram

   Configure in sequence: 1. Edit Fields node: jsonOutput is {} in the source, possibly a placeholder; supplement with actual field mappings as needed or keep as-is. 2. HTTP Request node (Upload Bloatato): POST https://backend.blotato.com/v2/media, body parameter url from Google Sheets Video URL (google drive). 3. HTTP Request node (Publish to IG): POST https://backend.blotato.com/v2/posts, JSON body includes Instagram target platform, caption text (Caption.toJsonString()), media URL (url from previous step), and accountId (must replace {{ YOUR_INSTAGRAM_ID }} with your actual Instagram account ID). 4. Google Sheets node (Google Sheets1): operation appendOrUpdate, matchingColumns set to Video URL (google drive), update Status to 'Posted'.

You are setting up an n8n workflow to auto-generate Instagram Reels from a chat message. First confirm these prerequisites:
- Accessible n8n instance (cloud or self-hosted)
- openAiApi credential configured (GPT-4 access)
- httpHeaderAuth credential configured (Wavespeed API key + Blotato API key)
- googleSheetsOAuth2Api credential configured
- Google Sheets tracking spreadsheet created with columns: Video Description / Prompt, Video URL (google drive), Caption, Status
- Blotato Instagram accountId obtained

Once confirmed, import workflow.json or create nodes manually, checking:
1. AI Video Prompt Agent system prompt copied in full
2. Veo3 Video Generator body parameters (aspect_ratio, duration, prompt variable)
3. HTTP Get Request URL template and polling logic
4. If node condition (data.status equals processing)
5. Caption Agent system prompt and model selection
6. Google Sheets node documentId, sheetName, field mappings
7. Publish to IG node accountId replaced with real value

Trigger with a test message to verify Veo3 generation, polling, caption, spreadsheet logging, and Instagram publishing.