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Sinan Koçak
Sinan Koçak

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How I Built a $2,400/Month Passive Income Stream Using AI to Auto-Generate and Sell Niche API Documentation

#ai #automation #productivity #webdev

The Problem Nobody Talks About

Thousands of developers publish open-source libraries every month. Most of them have terrible documentation. That gap is a goldmine.

I built a fully automated pipeline using GPT-4 and GitHub Actions that scrapes underserved npm packages, generates professional documentation sites, monetizes them with ads and affiliate links, and earns me $2,400/month with about 2 hours of oversight per week.

Here's exactly how I did it.

The Core Technique: AI-Powered Doc Site Factory

The strategy is simple:

  1. Find npm packages with 500–5,000 weekly downloads but poor README files
  2. Auto-generate full documentation sites using AI
  3. Deploy them to Vercel for free
  4. Monetize with Carbon Ads and affiliate links to relevant dev tools

Step-by-Step Implementation

Step 1: Find Your Targets

Use the npm registry API to identify candidates:

const response = await fetch(
 'https://registry.npmjs.org/-/v1/search?text=keywords:utility&popularity=0.5&quality=0.3&size=50'
);
const packages = await response.json();
const underserved = packages.objects.filter(p =>
 p.package.description.length < 80 &&
 p.downloads.weekly > 500
);
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This surfaces packages people actively use but that lack solid docs.

Step 2: Generate the Documentation

Feed the package source code and README into GPT-4 with a structured prompt:

You are a senior technical writer. Given this npm package source code, generate:
- A full API reference with parameter tables
- 3 practical usage examples
- A troubleshooting section
- SEO-optimized meta description
Format everything in MDX.
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GPT-4 produces publication-ready MDX in under 30 seconds per package.

Step 3: Auto-Deploy with GitHub Actions

Your workflow triggers nightly:

name: Doc Factory
on:
 schedule:
 - cron: '0 2 * * *'
jobs:
 generate:
 runs-on: ubuntu-latest
 steps:
 - name: Generate and push docs
 run: node scripts/generate-docs.js
 - name: Deploy to Vercel
 run: vercel --prod --token=${{ secrets.VERCEL_TOKEN }}
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Each new site gets its own subdomain: packagename.yourdocshub.com

Step 4: Monetization Stack

  • Carbon Ads: $1–4 CPM, developer-focused audience converts well
  • Affiliate links: Link to relevant courses on Udemy or tools on RapidAPI
  • "Improve these docs" GitHub sponsor button: Some maintainers actually pay

Real Numbers After 6 Months

Month Sites Live Monthly Revenue
1 12 $180
2 34 $490
3 71 $920
6 190 $2,400

Top performers earn $40–$80/month each. Most earn $8–$15. It's a volume game.

API costs run about $60/month for GPT-4 calls. Vercel and domain costs add another $40. Net margin sits around 95%.

What Makes This Work

The key insight is search intent. Developers Googling packagename examples or packagename API reference have zero ad-block mindset. They want information, they find your clean site, they click contextual ads naturally.

You're not gaming anything. You're genuinely filling a content gap that serves the community.

Getting Started Today

You can validate this in a weekend. Pick 5 packages manually, generate docs with a ChatGPT prompt, deploy to Vercel, and add a Carbon Ads unit. If you get 200 page views in week one, automate the rest.

The automation ceiling is high. I haven't hit it yet.

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