Short answer
An API is a defined way for one piece of software to request data or actions from another: a checkout asking a payment gateway to take a GCash payment, or a dashboard pulling yesterday’s sales from an accounting system. Both sides agree on the format in advance, so neither needs to know how the other works internally.
Also called: API, REST API, Web service
For a buyer, the practical question about any system is whether it has one and what it exposes. A platform without an API is a place data goes in and does not come out, which turns every future integration into manual re-entry or an export-and-import routine somebody has to remember to run. Asking for the API documentation before signing is a cheap way to find out what a vendor actually allows.
An API you depend on is also a dependency someone else controls. Providers change pricing, impose rate limits on how many requests are allowed per minute, deprecate old versions and occasionally shut services down. Integrations survive that better when the connection is isolated behind one module rather than scattered across the codebase, and when the failure behaviour is decided during the build: what the app should do when the payment gateway does not answer.
Where this comes up in our work
Related terms
Headless CMS
A headless CMS stores content without controlling how it is displayed: editors work in an admin interface, and the content is delivered to a website, mobile app or in-store screen through an API.
Database
A database is the structured store behind an application: customers, orders, bookings and stock held in a form software can query reliably.
Custom Software vs Off-the-Shelf Software
Custom software is built for one organisation’s specific process; off-the-shelf software is a finished product many organisations subscribe to, such as Shopify or QuickBooks.
AI Agent
An AI agent is a system that uses a language model to decide which actions to take, then takes them through connected tools: reading a database, sending an email, updating a booking record.
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