LinkedIn's algorithm rewards consistent, high-quality posts. But writing LinkedIn content is time-consuming. The format demands longer, more thoughtful posts than X or Instagram. This guide shows you how to generate LinkedIn posts programmatically using a REST API.

Why LinkedIn is different

LinkedIn posts have unique characteristics that AI needs to understand:

  • Character limit: 3,000 - much longer than X's 280
  • The fold matters. Only ~210 characters show before "See more." The hook must be in that window.
  • Formatting drives engagement. Line breaks, bullet points, and short paragraphs perform best.
  • Professional but personal. The best LinkedIn content tells stories with professional lessons.
  • Hashtags at the bottom. 3-5 hashtags, not inline.

A generic AI prompt won't account for these rules. A purpose-built content API will.

Authentication

All requests require a Bearer token. Get your API key from the SupaPost dashboard after signup:

Authorization: Bearer sp_your_api_key_here

Generate a LinkedIn post

Use the unified content generation endpoint with platform: "linkedin":

curl -X POST https://api.supapost.ai/api/v1/content/generate \
  -H "Authorization: Bearer sp_your_key" \
  -H "Content-Type: application/json" \
  -d '{
    "type": "social",
    "platform": "linkedin",
    "topic": "Why most startups fail at content marketing"
  }'

Response format

{
  "type": "social",
  "platform": "linkedin",
  "content": "Most startups treat content as an afterthought.\n\nThey hire one writer, give them zero context, and expect viral posts.\n\nHere's what actually works:\n\n1. Define your voice BEFORE you write anything...\n\n#ContentMarketing #Startups #Growth",
  "variations": [
    "I've seen 50+ startups fail at content marketing...",
    "Hot take: Your content strategy is failing because..."
  ],
  "hashtags": ["ContentMarketing", "Startups", "Growth"]
}

The response includes the primary post (formatted for LinkedIn with line breaks and hashtags at the bottom), 2 alternative variations, and extracted hashtags.

Brand context matters

The quality of generated content depends on your workspace settings. Before making API calls, ensure your workspace has:

  • Brand voice set (professional, bold, educational, etc.)
  • Industry configured (SaaS, Finance, Healthcare, etc.)
  • Target audience defined (startup founders, marketing managers, etc.)
  • Content pillars listed (product updates, industry insights, etc.)

The fastest way: enter your website URL during onboarding. The AI auto-detects all of these settings.

Batch generation for the week

Use the strategy endpoint to plan a full week of LinkedIn content:

curl -X POST https://api.supapost.ai/api/v1/strategy/generate \
  -H "Authorization: Bearer sp_your_key" \
  -H "Content-Type: application/json" \
  -d '{
    "topic": "B2B SaaS growth strategies",
    "platforms": ["linkedin"]
  }'

This returns a strategy with multiple content pieces, each with suggested posting times optimized for LinkedIn engagement.

Best practices

  1. Generate variations. The API returns 2-3 per request. A/B test them.
  2. Edit the hook. AI generates good hooks, but your personal touch makes them great.
  3. Post at optimal times. Tuesday-Thursday, 8-10am in your audience's timezone.
  4. Use the repurpose endpoint. Turn your best LinkedIn posts into X threads, blog intros, or newsletter sections.
  5. Track what works. Use the usage API to monitor generation volume and adjust your content pillars based on performance.

LinkedIn rewards consistency more than virality. With API-powered generation, posting daily becomes sustainable instead of exhausting.