What Is an API Endpoint

An API endpoint is a specific web address that a piece of software sends a request to in order to do one particular thing, like posting a caption, fetching a list of followers, or uploading an image. If an API is the overall system a service exposes for other software to talk to, an endpoint is one specific door into that system.

API endpoint meaning: one address, one job

A single API is usually made up of many endpoints, each handling a narrow task. A social platform's API might have one endpoint for creating a post, a different one for reading comments, and another for uploading media, all under the same overall API but each with its own address and its own expected input.

What is a REST endpoint, specifically

Most social platform APIs today are REST APIs, meaning each endpoint is a normal-looking URL, and what happens when you hit it depends on the HTTP method used alongside it:

• GET a URL to retrieve information (like reading a list of recent posts).
• POST to a URL to create something new (like publishing a caption).
• DELETE to a URL to remove something (like taking down a scheduled post).

The same endpoint address can sometimes behave differently depending on which of these methods is attached to the request.

Walkthrough: one call to a social posting API

Say a scheduling tool needs to publish a caption to an account. In simplified form, the request looks something like this:

POST https://api.example-platform.com/v2/posts
Authorization: Bearer <access_token>
Body: { "caption": "New post text", "media_url": "..." }

The endpoint is /v2/posts. The method is POST, because something new is being created. The Authorization line proves the request is allowed to post on that account's behalf. The body carries the actual content. The platform's server receives this, checks it's valid, publishes the post, and sends back a response confirming it worked (or an error explaining why it didn't).

Endpoint vs. API meaning: don't mix them up

"API" refers to the whole interface a service offers. "Endpoint" refers to one specific address within that interface. Saying "call the API" is a bit like saying "go to the mall"; saying "call the posts endpoint" is more like naming the exact store.

Reading the response, and when it says no

A well-built API returns a status code alongside its response: 200 means the request succeeded, 401 means the request's credentials weren't valid, 404 means the endpoint or resource doesn't exist, and 429 means you've hit a rate limit and need to slow down. Most endpoints also enforce a rate limit, a cap on how many requests you can send in a given window, specifically to stop one application from overwhelming the service. Handling these responses gracefully, rather than assuming every request succeeds, is most of what separates a reliable integration from a fragile one.

You rarely need to touch this directly

Every platform Posted Once connects to (X, Instagram, Facebook, LinkedIn, TikTok, YouTube, Pinterest, Bluesky, Threads, and Google Business Profile) has its own posting endpoints, its own authentication rules, and its own quirks in what a request needs to include. Posted Once handles those endpoint calls behind the scenes so you're writing a caption in one interface, not learning ten different APIs. Start scheduling free →