What was used before APIs became the standard?

Question

I’m not in the IT sector but I’m beginning to understand the logic behind sending requests and receiving responses for various reasons. What was used before APIs became the standard for communication between systems?

Edit: I understand now that I’ve been in fact asking about REST API.

In: Technology

Answer 1

Before REST with HTTP verbs and JSON data formats became standard it was mostly proprietary API with different data types (often XML). Same concept (send text representation of objects using http. Get back a text response and interpret it as an object. ). Just less standard and more documentation heavy