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Alex Spinov
Alex Spinov

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Polar Has a Free API: The Open-Source Billing Platform That Lets You Monetize Your Developer Project in 10 Minutes

#webdev #programming #api #opensource

You built an open-source tool that thousands of developers use. Your GitHub repo has 2,000 stars. But your "Buy Me a Coffee" button generated $12 last year. The problem isn't that people don't want to support you — it's that existing monetization tools weren't built for developers. Polar was.

What Polar Actually Does

Polar is an open-source billing and monetization platform built for developers and OSS maintainers. Think Stripe plus GitHub Sponsors, with a developer-first API. It handles subscriptions, one-time donations, issue funding, and digital product sales.

Polar is open-source (Apache 2.0), self-hostable, but their hosted platform at polar.sh charges zero monthly fee — just a small transaction percentage. The REST API uses OAuth2 or API keys.

The critical difference from Patreon: Polar integrates with GitHub. Fund specific issues, reward contributors, automate benefits like private repo access for paying subscribers.

Quick Start

Get your API token from polar.sh Settings > Developers > New Token.

export POLAR_TOKEN="your_token_here"

# List your products
curl -s https://api.polar.sh/v1/products \
  -H "Authorization: Bearer $POLAR_TOKEN" | jq '.items[] | {id, name, price_amount}'
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Create a subscription tier:

curl -X POST https://api.polar.sh/v1/products \
  -H "Authorization: Bearer $POLAR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Pro Supporter",
    "description": "Priority issue responses + private Discord",
    "prices": [{
      "type": "recurring",
      "amount_type": "fixed",
      "price_amount": 900,
      "price_currency": "usd",
      "recurring_interval": "month"
    }]
  }'
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Check active subscribers:

curl -s "https://api.polar.sh/v1/subscriptions?active=true" \
  -H "Authorization: Bearer $POLAR_TOKEN" | jq '.items | length'
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3 Practical Use Cases

1. GitHub Issue Funding

Let users pledge money for specific bugs or features:

curl -s "https://api.polar.sh/v1/issues?is_badged=true" \
  -H "Authorization: Bearer $POLAR_TOKEN" | jq '.items[] | {
    title, funding_goal: .funding.funding_goal.amount,
    pledged: .funding.pledges_sum.amount
  }'
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Embed a funding badge in your README:

[![Fund with Polar](https://polar.sh/embed/fund-label.svg)](https://polar.sh/your-org)
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When you close a funded issue, Polar splits the reward between contributors.

2. Automate Benefits with Webhooks

Grant GitHub private repo access when someone subscribes:

app.post('/polar/webhook', async (req, res) => {
  const event = JSON.parse(req.body);
  if (event.type === 'subscription.created') {
    const github = await lookupGitHubUser(event.data.customer.email);
    await addCollaborator('your-org/private-repo', github, 'pull');
  }
  res.sendStatus(200);
});
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3. Checkout Links for Digital Products 

curl -X POST https://api.polar.sh/v1/checkouts/custom \
  -H "Authorization: Bearer $POLAR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "product_id": "YOUR_PRODUCT_ID",
    "success_url": "https://yoursite.com/thank-you",
    "customer_email": "user@example.com"
  }' | jq '{checkout_url: .url}'
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Embed it in your README — every click goes to checkout with email pre-filled.

Why This Matters

Open-source sustainability is broken. Polar is the first platform that understands the developer workflow: GitHub-centric, API-first, developer-controlled. The issue funding model changes the dynamic — instead of hoping people donate, users can fund the features they want.

Zero monthly fee, clean API, and GitHub integration. If you maintain any OSS project with users, set up Polar before burnout hits.

Need custom data extraction or web scraping solutions? I build production-grade scrapers and data pipelines. Check out my Apify actors or email me at spinov001@gmail.com for custom projects.

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