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Diptesh Bal
Diptesh Bal

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From Manual to Magic: How I Used Keploy to Test APIs on YouTube and Amazon

APIs are the backbone of modern web apps, but testing them? That’s where many devs, including me, used to burn time.

Recently, I discovered Keploy, an AI-powered API testing tool, and decided to try it out on two API-heavy websites I use often: YouTube and Amazon. Spoiler: I went from zero test coverage to 100% functional coverage of real-world user flows — in minutes.

Here’s how it went, what I learned, and why I think AI might just be the future of API testing.


Why YouTube and Amazon?

Both of these websites are API monsters:

  • YouTube: Every search, video load, comment, and recommendation is driven by background API calls.
  • Amazon: From product listings to price and shipping info, nearly everything on a product page is dynamically fetched.

Perfect targets to stress test an API testing tool.


Getting Started with Keploy

Setting up was smooth:

  1. Installed the Keploy API Testing Chrome Extension.
  2. Browsed YouTube and Amazon like a normal user — searched, clicked, scrolled.
  3. Keploy silently recorded the API calls in real-time.

Within seconds, I had a test suite auto-generated from real user interactions.


Testing YouTube

Keploy captured calls like:

  • GET /search (video search)
  • GET /watch (load video details)
  • GET /comments (load comments)

I replayed these through Keploy. It verified responses and flagged mismatches, especially for dynamic values like timestamps or suggestion IDs.

What stood out:

  • Keploy caught minor changes I wouldn’t notice manually.
  • No Postman. No scripting. Just record and replay.

Testing Amazon

Amazon was even more API-rich. Keploy captured:

  • Product list API (search)
  • Product detail API (price, availability, ratings)
  • Shipping estimate API

Amazon’s APIs return a lot of dynamic data (e.g., offer IDs, tracking info), which occasionally caused false negatives on replays. Still, a few tweaks to filters and I was golden.


Manual vs. Keploy: A Quick Comparison

Task Manual Testing Keploy + AI
Capture API traffic DevTools/Charles, manual Automatic
Write test scripts Manually, one by one Auto-generated
Handle dynamic values Tedious Smart comparison engine
Replay tests Postman/cURL One-click in dashboard
Time spent Hours ~10 minutes

Challenges I Faced

  • Dynamic tokens & sessions: Amazon's APIs return session-bound data. Replays required small tweaks or tokens.
  • Authentication: Some calls are gated. Keploy works best during real authenticated sessions.
  • Noise filtering: Sites like Amazon fire tons of tracking APIs — it helps to focus only on the key business logic calls.

Why I’m Excited About AI Testing

Keploy flipped the API testing game for me. Here's what stood out:

Zero test writing — everything came from real user sessions.

Quick feedback loops — replaying tests after changes is painless.

High confidence — I actually trust my coverage now.

As devs, we’re always chasing better velocity without compromising quality. AI tools like Keploy seem to be closing that gap — fast.


Final Thoughts

If you’re a dev or tester who’s still manually writing API tests or maintaining brittle test suites — give Keploy a shot.

✅ Record real traffic

✅ Auto-generate tests

✅ Replay and verify responses

It's not magic. But it kind of feels like it.


Your turn: Have you used AI-based tools for API testing?

Drop your thoughts in the comments — I’d love to compare notes.


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