DEV Community

Cover image for Auto-Post to 9 Platforms with Claude Code and Zernio
Darya Nazarava
Darya Nazarava

Posted on

Auto-Post to 9 Platforms with Claude Code and Zernio

#socialmedia #api #automation #claude

What you'll build: An agent that analyzes video or images and generates platform-optimized captions, hashtags, and titles—then publishes to 9 social platforms at once.

The problem

Manual posting kills momentum. You format content for Instagram, then rewrite everything for TikTok. Again for LinkedIn. Again for X. A single video turns into a 2-hour job.

With this setup, one prompt becomes nine scheduled posts - captions, hashtags, and format conversions all handled automatically.

What you need

  • A Zernio account (free tier: 2 platforms)

  • Claude Code installed

  • 30 minutes to set up; 5 minutes per post after

Step 1: Connect platforms in Zernio

Zernio is the layer that handles the actual platform integrations. Without it, you'd need to build separate OAuth flows, API integrations, media handling, and rate-limit management for each platform (months of work before Claude could publish a post).

With Zernio, that's already done. Claude talks to one API; Zernio handles the cross-platform part.

  1. Log in at zernio.com

  2. Go to your profile and click Connect platform for each account you use (Instagram, TikTok, X, YouTube, LinkedIn, Threads, Pinterest, etc.)

  3. Authorize Zernio for each

  4. Verify each shows in your dashboard

Step 2: Get the Zernio Publishing skill

The skill includes platform-specific guidelines for 9 platforms -hashtag rules, character limits, format specs, tone cues. You're not training Claude from scratch.

  1. Download the skill from the Zernio library GitHub repo

  2. Extract the zip

  3. You'll get:

zernio-library-skills/
├── .claude/
│   └── skills/
│       ├── zernio-publish/                    ← the publishing skill
│       │   ├── SKILL.md
│       │   ├── reference/                       deep API + per-platform docs
│       │   └── templates/manifest.json
│       └── skill-creator/                     ← Anthropic's official skill-creator
│                                                  bundled for when you add more skills
├── .env                                       ← ZERNIO_API_KEY (placeholder until you fill it)
├── CLAUDE.md                                  ← architectural map of the repo
├── README.md
├── LICENSE                                    ← MIT
└── .gitignore
Enter fullscreen mode Exit fullscreen mode

Keep the folder structure intact. Claude needs reference/platforms/ to look up rules when writing captions.

Step 3: Add the skill to your project

  1. Open VS Code or use Claude Code / Cowork directly

  2. Create a new folder for this project or use an existing one

  3. Extract the zip and copy the entire folder to your project root

  4. Your file tree should show .claude/zernio-publishing/ at the top level

In Cowork: Go to Skills → + Create skill → Upload skill and select the folder.

Step 4: Set up your API key

Claude needs a Zernio API key to publish.

  1. Log in to Zernio

  2. Go to API keys (settings)

  3. Click Create key, name it (e.g., "claude-publishing")

  4. Copy it

Create a .env file in your project root:ZERNIO_API_KEY=your-key-here

Claude Code reads this automatically—never paste keys into prompts.

Step 5: Test with a simple prompt

Start with one video and 2–3 platforms to confirm the skill works.

Give Claude this:

I have a short-form video at [path/to/video.mp4]. Can you analyze it, create optimized posts for Instagram, TikTok, and LinkedIn, and schedule them using Zernio?

Claude will:

  1. Load the skill and platform guidelines

  2. Analyze your video

  3. Generate captions, hashtags, titles, and first comments

  4. Call Zernio to stage the posts

  5. Show you a preview before publishing

Step 6: Review before you approve

Claude shows all posts before publishing. You control what goes live.

You'll see something like:

post drafts in claude

Request changes if needed. Say "Approve" when it looks good.

Note: First comments are easy to miss if you skim the preview. Read the full output before approving—Instagram, TikTok, and LinkedIn generate engagement hooks you might not see at first glance.

Step 7: Scale to multiple platforms

Once you're confident with a few, the system handles format conversion and batching automatically.

You can:

  • Post to 9 platforms at once: Video or carousel becomes optimized for each platform's native format

  • Convert formats: Carousels become videos for platforms that don't support multi-image

  • Batch multiple assets: Claude processes everything and schedules it all

Example:

I have a carousel at [Google Drive link] and a 30-second clip at [path]. Convert the carousel to video and post both to Instagram, TikTok, X, YouTube, LinkedIn, and Threads. Optimize each for that platform. Schedule for tomorrow at 9 AM.

What's next

You own a system that turns one prompt into nine scheduled posts—all optimized and formatted. A video that took 2 hours to post manually now takes 5 minutes to set up and approve.

The time saved compounds. This week: 2 hours back. Next month: 20+ hours back. That's time spent creating instead of grinding.

Check posts in Zernio or directly on each platform. Track analytics and iterate. The system learns as you refine your voice.

scheduled posts in zernio dashboard

Questions or running into issues? Drop them in the comments.

Top comments (0)