An API (application programming interface) is a set of rules and protocols that lets one piece of software talk to another, usually by sending requests and receiving structured responses over a network. In practice, it’s the “contract” that defines what you can ask a service to do (endpoints, parameters) and what you’ll get back (data formats like JSON or XML).

Quick Scoop: What “what api” could mean

Since your post title is just “what api,” you might be asking any of these:

  • What is an API, in simple terms.
  • What API to use for a specific task (e.g., news, weather, payments).
  • What kind of API style (REST, GraphQL, etc.) is best for a project.

Below I’ll give a quick, high‑level “forum style” breakdown that fits your content rules (mini sections, bullets, etc.).

1. What an API is (human-style explanation)

Think of an API as a menu at a restaurant: it tells you what you can order and what you’ll get, without you seeing the kitchen.

  • The “restaurant” is a remote service (e.g., a weather provider, payment gateway, social network).
  • The “menu items” are API endpoints like /weather, /charge, /posts.
  • You send a request (with parameters like city, amount, or user id), and you get back a response (the data you asked for) in a defined format.

Because APIs hide the internal complexity, different apps can be built quickly just by wiring APIs together (for payments, login, notifications, etc.).

In 2026, almost every serious web or mobile app you see is basically a bundle of APIs stitched together—from auth to analytics to content feeds.

2. Common types of APIs you’ll hear about

Different “what API?” questions often boil down to “which style of API should I use?” These are the big ones:

  • REST APIs
    • Use HTTP verbs (GET, POST, PUT, DELETE) with URLs like /users/123.
* Usually return JSON, are stateless, and are the default choice on most modern backends.
  • SOAP APIs
    • Older, XML-based, very strict protocol, often used in enterprise, banking, and regulated industries where formal contracts and security are key.
  • GraphQL APIs
    • You send a query that describes exactly what data you want and get just that, often from multiple resources in one call.
* Great when you need to optimize for mobile/slow networks or reduce over‑fetching/under‑fetching.
  • gRPC / RPC APIs
    • High‑performance, often used between microservices; gRPC uses HTTP/2 and Protocol Buffers for speed and compact messages.
  • WebSocket APIs
    • Keep a connection open and allow real‑time, two‑way communication (chat, live dashboards, games).

3. “What API should I use?” by use case

When people ask “what API?” they often really mean “for this problem, what’s a good API or API style?”

By problem you’re solving

  • News or content
    • Use a news/content REST API that gives JSON articles (title, description, URL, image, etc.).
* Example capabilities: filter by date (`Y-m-d`), categories, language, etc.
  • Weather
    • Typical: REST API returning JSON data for current/forecast weather; you send location, it returns temperature, conditions, etc.
  • Payments
    • Use a payment gateway’s REST or SOAP/REST‑hybrid APIs; they handle security, card processing, webhooks, etc.
  • Social media integration
    • Platform‑specific REST/GraphQL APIs (e.g., social networks provide endpoints for posts, profiles, analytics).
  • Internal microservices
    • Often gRPC or REST; gRPC is favored where low latency and high throughput matter.

By accessibility

APIs are also categorized by who can use them:

  • Open / public APIs – Anyone with a key can sign up and call them (e.g., many news, weather, crypto APIs).
  • Partner APIs – Only specific partners/businesses get access (often for payments or logistics).
  • Internal APIs – Only used inside a company, between its own services.

4. Mini table: API styles at a glance

[5][3][9] [3] [1][5][3] [5][3] [1][7][9] [1][7][9] [7][3][9] [3][7][9] [3] [3]
API style Best for Data format Pros Cons
REST Web & mobile backends Usually JSON Simple, stateless, widely supported.Can over‑fetch or under‑fetch data.
GraphQL Complex UIs, multiple data sources JSON Fetch exactly what you need in one query.More complex server setup, query management.
SOAP Enterprise & regulated industries XML Strict contracts, built‑in error handling and security.Verbose, harder to work with, slower.
gRPC Microservices, internal systems Binary (Protobuf) Very fast, efficient, great for service‑to‑service.Not as human‑friendly, tooling more specialized.
WebSocket Real‑time apps (chat, trading) Text/binary frames True bidirectional, low‑latency updates.More complex connection management.

5. If you meant “what API for this project?”

If your original “what api” was meant for something specific (like: what API to pull latest news for a site , or which API style to design my backend), tell me:

  1. What you’re building (site/app, internal tool, hobby project, etc.).
  2. What data or actions you need (e.g., headlines, payments, chat, analytics).
  3. Any constraints (free vs paid, low latency, must be very simple, etc.).

Then I can give a much more targeted “use this type of API, avoid that one, start with these endpoints” answer. Bottom note: Information gathered from public forums or data available on the internet and portrayed here.