Test Environments are Expensive, Time-Consuming and Unreliable
When your application uses web services as backends, you are forced to test not only your own code but the configuration, data seeding, hardware capacity and support processes of each of those backends.
They cost hundreds of dollars a week.
They have to be reserved. And retained if your project is late.
They have to be seeded with matching accounts.
They go down in the middle of your testing.
They cannot handle the load.
They tend to have a wrong code version.
They are slow to troubleshoot.
Worst of all, you have to deal with these problems anew every release.
Mock the APIs, Save Time, Money and Sanity
The web services can be very complex, but their output is usually straightforward, and it can be mocked (a.k.a simulated, a.k.a. virtualized). Replace expensive, hard-to-reserve, unreliable and slow backend services with their mocked versions, and you can regain control over your project schedule and budget.
You don’t have to pay for each mock service separately.
You don’t have to ask for a lease from anyone.
You seed mock services from a spreadsheet, all services at once.
Mock services are never down, on maintenance or under deployment.
They can support the heavy load of your LT or PTE tests.
You don’t have to wait for backend’s code to become ready.
You own team can troubleshoot quickly.
Once you set mock services up, you can reuse them for many releases and projects.
... We've saved weeks and $$$ in LT by using mocks instead of PROD-like backends.