API
What is an API?
An API (application programming interface) is the agreed set of rules through which two pieces of software exchange data and trigger each other’s functions. It is what lets a shop read stock levels from a warehouse system, a site send an order into accounting, or a form create a record in a CRM without anyone retyping anything.
How it works
One program sends a request to a precisely defined address, such as “give me the stock of item 1042”, and the other answers in an agreed format, most often JSON. The API decides which requests are allowed, what data they return and who may make them: access is granted with a key that can be revoked.
Most systems a business works with have an API: couriers, payment providers, accounting software, CRM systems, Google and Meta.
Example
An online shop takes 50 orders a day. Without a connection, someone retypes every order into the accounting software and every waybill into the courier’s system: about two minutes per order, over an hour and a half a day, with the inevitable mistakes in addresses and amounts.
With a connection through the API, the order creates an invoice in accounting and a waybill with the courier the moment it is paid, and the tracking number returns to the shop and to the customer’s email.
Why it matters for a business
An API turns manual work between systems into automatic work and removes the errors of retyping. What a connection costs depends on both sides: how well the API is documented, how much data moves and what must happen when one system does not answer. So before choosing new software (a shop, a CRM, accounting) it pays to check that it has an open, documented API.
What to ask
- Does the software have a public, documented API, or does the connection rely on exported files?
- What happens to an order if the other system is briefly down: does it wait and retry?
- Who holds the access keys and how are they revoked?
- Is there a limit on the number of requests, and is it enough on the busiest days?
When a site, a shop, a warehouse and accounting have to talk to each other, the API is the link between them. We build such integrations in our web software work.