The idea, plainly.
WHAT IT IS
A defined way for one program to ask another program to do something.
WHAT DEFINED MEANS
Both sides agree on the addresses, the format of requests, and the format of replies.
WHY THAT AGREEMENT IS THE WHOLE POINT
Neither side needs to know how the other works internally.
WHAT THAT ENABLES
Systems built by different people, at different times, working together.
WHAT A WEB API IS
One reached over the internet, usually using the same protocol as web pages.
WHY THAT CHOICE
The infrastructure already exists everywhere: addresses, encryption, caching, proxies.
WHAT AN API IS NOT
A user interface A database you can query freely A promise that the other system is available
WHAT AN INTEGRATION IS
Two systems connected so that something in one causes something in the other.
WHAT THE API IS IN THAT PICTURE
The mechanism, not the integration itself.
WHY THE DISTINCTION MATTERS
Most integration work is deciding what should happen, not calling the endpoint.
WHAT THE HARD PARTS ACTUALLY ARE
Deciding which system owns each fact Handling failure Keeping data consistent Knowing when something did not happen
WHAT PEOPLE UNDERESTIMATE
That every integration is a permanent relationship requiring maintenance.
WHAT TO ESTABLISH BEFORE BUILDING ONE
Who owns it when it breaks.
