How an API Works

Think of an API like ordering at a restaurant counter instead of walking into the kitchen. You (the client) place a specific request from a menu (the API’s endpoints), and the kitchen (the server) hands back exactly what you asked for — you never need to see how it was made.

Technically, an API request usually includes:

• An endpoint URL — the address you’re sending the request to 
• A method — what you want to do (GET to retrieve data, POST to submit data, etc.)
• Headers — metadata about the request, often including an API key for authentication
• Parameters — filters that shape the response 

The server responds with structured data, usually in JSON format, that a program can immediately read and use — no interpretation needed.

Example: A weather app doesn’t guess the temperature — it calls a weather provider’s API, sends a city name, and gets back a clean response like {“city”: “Austin”, “temp_f”: 91}. The app just displays it.

Types of APIs

• Public APIs — Open for anyone to use, sometimes with usage limits (e.g., a public sports scores API).
• Partner APIs — Shared only with approved business partners under an agreement.
• Internal APIs — Used privately within a single company’s own systems.
• Scraping APIs — A service that returns data extracted from a website that doesn’t offer its own public API — the scraping API does the extraction work and hands back structured data, the same way any other API would.

APIs and Web Scraping

Web scraping and APIs are often talked about as opposites, but they’re really two ways to get the same job done — pulling data out of a website.

• If a site has an API, use it. It’s faster, more stable, and the data owner has explicitly built it for this purpose. Example: Twitter/X’s API lets developers pull tweets directly, instead of extracting them from the page.
• If a site has no API (most e-commerce, real estate, and news sites don’t offer one), scraping fills the gap — extracting the same data straight from the page itself.
• Scraping-as-a-service products blend the two. A provider like ScrapeHero handles the messy part — rotating proxies, solving CAPTCHAs, rendering JavaScript-heavy pages — and hands the result back through a simple API call. So even though scraping is happening under the hood, the end user experiences it exactly like using any other API.

This is why the first question in most data projects is “does this site have an API?” — and why a scraping API is often the practical answer when it doesn’t.

Common Challenges and Misconceptions

• If there’s no public API, the data isn’t accessible.

Not true — a lack of a public API just means there’s no sanctioned machine-access point; the data may still be extractable through compliant scraping methods.

• APIs aren’t always free or unrestricted.

Rate limits, paywalls, and tiered pricing are common, and some APIs offer only a fraction of the data visible on the actual website.

• API stability varies. 

Companies can deprecate, version, or restrict APIs with little notice, which is why some data teams rely on a scraping layer as a fallback even when an API exists.

• “API” and “scraping API” are not the same thing.

The former usually refers to a company’s own data endpoint; the latter refers to a third-party service that extracts data on the requester’s behalf.

Need structured data from a site without a public API? See how ScrapeHero’s managed scraping API delivers clean, reliable data on demand.