n8n Workflow: Generate Social Captions with OpenAI

Turn blog posts into ready-to-post social captions with OpenAI (for n8n)

This n8n workflow takes a blog URL (or pasted blog text) and automatically generates platform-specific social captions—plus featured image alt text—using OpenAI, returning a styled HTML results page you can copy directly.

What this workflow does

• Collects input via an n8n form: You submit a blog URL or paste the blog text, and you can optionally include a featured image URL.
• Fetches and extracts article text: If you provide a blog URL, the workflow downloads the page with an HTTP request and extracts readable article content from the HTML; otherwise it uses the pasted text.
• Generates captions as strict JSON: It builds one prompt asking OpenAI for platform-specific captions (including a Twitter/X thread) and for featured image alt text, returned as strict JSON.
• Converts JSON into copy-ready HTML: The JSON output is transformed into a styled HTML page with one section per social network and copy buttons for easy reuse.

Use cases

• SaaS marketing ops: Repurpose every new blog post into captions for multiple social platforms in minutes.
• Automation engineers: Use a clean OpenAI-to-HTML pattern to standardize content generation workflows in n8n.
• Content teams: Provide alt text guidance for featured images to keep social posts more accessible (especially for Instagram/Pinterest).

Technical details

• OpenAI integration via an “OpenAI Chat Model” node (configure your OpenAI API credential and select the model).
• n8n nodes used: if, code, form, sticky note, form trigger, http request.
• Prompting + output formatting: OpenAI is instructed to return strict JSON, which is then rendered into the final HTML results page.

Setup (quick)

• Add your OpenAI API credential to the OpenAI Chat Model node.
• Activate the workflow and open the Blog Input Form production URL to submit a blog URL or pasted content.
• If using the URL option, ensure the blog page is publicly accessible.