Partial Mock APIs — httpdrop Guides

The problem: blocking backend dependency

You're building a checkout screen. The backend has 12 endpoints — 8 are ready, but the 4 most critical ones (shipping calculation, coupon validation, payment processing, and order confirmation) are still in development. Should the frontend team wait?

No. The Partial Mock technique lets you selectively replace only the missing endpoints while everything else keeps pointing at the real server.

App / Frontend

→

httpdrop
intercepts 4 mock endpoints

→ mock
→ real

Mock response
endpoints in dev

Real API
8 ready endpoints

How it works

1
Create an endpoint in httpdrop and configure Proxy Mode pointing to your real API base URL (e.g. https://api.myapp.com).
2
Switch the base URL in your frontend to the httpdrop endpoint (e.g. https://httpdrop.com/mock/ABC123). By default, all requests are forwarded to the real API.
3
Create Mock Rules only for the endpoints that need mocking. httpdrop intercepts those routes and returns the simulated response — everything else goes straight to the real server.

Use cases

🛒

E-commerce — Mock shipping calculation and payment processing while catalog and search hit the real staging API.

🏦

Fintech — Simulate credit approval/denial and invoice generation without touching the banking staging environment.

🧪

Edge case testing — Force a timeout response (using a Delay rule) on a specific endpoint to test your frontend's error handling.

Quick example

Mock Rule for POST /checkout/payment

{
  "method": "POST",
  "path": "/checkout/payment",
  "status": 200,
  "body": {
    "transactionId": "{{uuid}}",
    "status": "approved",
    "amount": "{{req.body.amount}}"
  }
}

The frontend has no idea it's receiving simulated data. When the backend is ready, just remove the rule and traffic returns to the real server — no frontend code change needed.

💡

Tip: Use httpdrop's request history to compare the simulated response against the real one once the backend endpoint is ready. Any divergence shows up in the automatic diff.