Generate Social Media Captions with OpenAI GPT-5 in n8n

Turn one idea into ready-to-post captions for every major social platform—automatically

This n8n workflow uses OpenAI GPT-5-mini to generate platform-specific social media captions from a single topic, then parses and validates each result for character limits and hashtag rules across Instagram, TikTok, YouTube Shorts, and Threads—returning a structured content report you can use immediately.

What this workflow does

• Manual run with a topic: Start the workflow when you manually execute it, then enter your content topic.

• Apply reusable content settings: Configure tone, target audience, language, brand voice, call to action, and whether you want emoji/hashtag preferences included.

• Generate captions via OpenAI: Send the topic and settings to OpenAI to produce distinct captions for:

• Instagram
• TikTok
• YouTube Shorts (title and description)
• Threads

• Parse and validate output: Break the single JSON response into separate platform fields, then verify presence, character counts, and that hashtag usage matches your configured rules.

• Return a structured content report: Includes generated content, the settings used, character counts, hashtag counts, and validation status.

Use cases

• SaaS operators quickly draft consistent posts for product updates, features, or launch announcements.

• Automation engineers build a reliable “caption factory” in n8n that enforces platform constraints before content goes live.

• Creators and marketing teams reuse the same topic and brand voice to produce variations for Instagram, TikTok, YouTube Shorts, and Threads.

Technical details

• Manual Trigger to run on demand

• OpenAI (n8n-nodes-langchain-open ai) using GPT-5-mini via your OpenAI API credential

• Nodes used include set, code, and a sticky note for workflow organization

• Generates a single JSON response, then parses, counts characters/hashtags, and validates limits and hashtag rules

Get started: Add your OpenAI credential in the “Generate Social Captions” node (ensure GPT-5-mini is available), replace the placeholder topic, then tune tone, audience, language, brand voice, and CTA to match your content strategy.