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Building an Open-Source Honey Alternative: The Caramel Story

7 months ago3 min read
open-sourcebrowser-extensionjavascriptcaramel

Honey was the most-installed browser extension in the world before PayPal acquired it. Then came the FTC investigation. Honey was quietly hijacking affiliate commissions from YouTubers and content creators — the very people who promoted it.

I built Caramel as the honest alternative.

What Honey Does (and Why It's Problematic)

Honey's business model was always suspicious in hindsight. It was free to users, but Honey got paid by merchants every time someone used a coupon. The conflict of interest: Honey would suppress better coupons to favor merchants who paid more.

The affiliate hijacking was worse. If you clicked a YouTube affiliate link and then used Honey at checkout, Honey replaced the creator's affiliate ID with its own. The creator got nothing. PayPal made money.

How Caramel Works

Caramel is fully open source at github.com/DevinoSolutions/caramel.

// The core coupon-finding loop
async function findBestCoupon(checkoutUrl) {
  const domain = extractDomain(checkoutUrl);
  const coupons = await fetchCoupons(domain);
  
  return await tryEachCoupon(coupons, (coupon) => ({
    code: coupon.code,
    savings: applyCoupon(coupon.code),
  }));
}

Key differences from Honey:

  1. No affiliate tracking — Caramel never touches your affiliate clicks
  2. Open source — anyone can audit what the extension does
  3. No data selling — browsing history stays on your machine
  4. Best coupon wins — no merchant-paid suppression

The Browser Extension Architecture

Chrome extensions have a 3-part architecture:

popup.html          ← User interface
background.js       ← Service worker, API calls
content-script.js   ← Runs on web pages, detects checkout

The tricky part is detecting when a checkout page appears. Different retailers have wildly different checkout flows. We use a combination of URL pattern matching and DOM observation:

// content-script.js
const checkoutPatterns = [
  /\/checkout/i,
  /\/cart\/checkout/i, 
  /\/payment/i,
  // ... 60+ patterns
];
 
function isCheckoutPage() {
  return checkoutPatterns.some(p => p.test(window.location.href)) 
    || document.querySelector('[data-checkout]') !== null;
}

iOS/macOS Safari Extension

The Chrome extension was straightforward. Safari on iOS was... not.

Apple requires Safari extensions to be wrapped inside a native iOS/macOS app distributed through the App Store. You write the extension in JavaScript, but you also write a native Swift wrapper app that Apple reviews.

The review process took 3 weeks and 2 rejections before approval. The review notes were: "Functionality unclear to reviewer during testing." (The reviewer didn't have coupon codes to test with.)

GitHub Stats After Launch

Within 3 months of launch:

  • 200+ GitHub stars
  • 40+ forks
  • 5 external contributors PRed improvements

The open-source community found edge cases we never would have caught solo. One contributor added support for 30 additional coupon sites in a single PR.

Lessons

Privacy is a feature, not a constraint. Users are increasingly aware of how free tools monetize them. Caramel's "we don't track you" message resonates.

Open source builds trust faster than marketing. The code is right there. If we were doing something sketchy, you'd know.

Platform distribution is everything. Getting into the Chrome Web Store and Firefox Add-ons is the hard part. Once you're there, installs compound.

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