K-Culture GlossaryAWords from the people who build
API
The window through which programs call on each other. When you hear "API released," it means "other apps can now plug this AI into their own products."
In plain words
An API (Application Programming Interface) is the window one program uses to call another. Think of a restaurant's order counter — you don't need to know how the kitchen (the AI model) works; you just submit your order in the right format and the dish comes out.
In AI news, "the API was released" means "other apps can now build on top of this AI." Translation apps, writing assistants, customer service chatbots — many AI products you use every day are actually placing orders at the API counters of OpenAI, Anthropic, or Google behind the scenes. The company that made the app and the company that made the AI are usually different.
This is also where billing happens, so API talk often comes with money talk. API pricing is charged per token ("dollars per million tokens"), and a price cut announcement is industry news because it means "building AI apps just got cheaper." It also helps to remember that the consumer subscription you pay for in a chatbot's interface is a separate thing from API pricing — keeping that straight makes articles much less confusing.
How it shows up in the news
"Halved the API price for the new model" — this signals lower costs for developers, which is often followed by a wave of expanded features across various AI apps.
Try it yourself
- See an API in its raw form. Type api.github.com into your browser's address bar — instead of a human-friendly page, you'll get a raw response meant for programs (a data package called JSON). This is how programs talk to each other.
- To try an AI API without writing code, search for "OpenAI Playground" or "Anthropic Console" — these are developer control panels that let you call the model directly, with no chatbot interface.
- Play with knobs like the system prompt or response length there. The difference between a chatbot app and this screen is the difference between a "finished product" and a "component (the API)" — the AI apps out in the world are built by assembling this component.
API vs. MCP: What's the Difference
A window developers wire up by hand, A shared standard AI uses on its own
Both get described as "connecting AI to the outside world," so they sound like two names for the same thing. But an API is a one-off window that differs from service to service, while MCP is an agreement to make all those windows the same shape. They sit at different layers — even a service that supports MCP is using an API underneath.
| Aspect | API | MCP |
|---|---|---|
| What it is | A separate ordering window for each service | A shared standard that unifies the shape of those windows |
| Who uses it | A developer writes code to call it | The AI itself picks and uses connected tools |
| Direction of the call | Usually an app calling on AI | Usually AI calling on outside tools |
| Cost of hooking up | 100 services means building 100 separate connections | Build to the standard once, and it plugs into any AI |
| Analogy | A restaurant's order counter | The USB-C connector standard |
| In articles | Comes up with money talk like price cuts and usage | Comes up with connection talk like agents and connectors |
Rule of thumbIf it's a story about an app calling on AI, it's API. If it's a story about AI calling on your tools and data, it's MCP.
API vs SDK: what's the difference
The window you call through, The toolkit that makes that window easier to use
The two always show up together in announcements. A sentence like "we released an API and an SDK" never explains what each one actually is. The relationship is simple - the API comes first, and the SDK is something the company builds on top to make that API easier to use. You can use the API without the SDK, but not the other way around.
| Aspect | API | SDK |
|---|---|---|
| What it is | The ordering window itself | A bundle of parts, docs, and examples for that window |
| Can you skip it | Without it, you can do nothing | You can skip it - it just takes more work |
| Whose is it | Language-agnostic. You just follow the rules | Released separately per language - one for Python, one for JavaScript |
| What the announcement means | Others can now build on our technology | Building on it just got much easier - a signal aimed at bringing in developers |
| Analogy | An order window | A helper kit that places the order for you |
Rule of thumbIf the story is that a capability got opened up, it's the API. If the story is that using that capability got easier, it's the SDK.
See also
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