How to Read an API Documentation?

When you're new to APIs, a API documentation page may look overwhelming. But once you know what each section means, reading any API becomes much easier.

Below we’ll walk through how to understand an API endpoint, how to build a request from it, and how to use the response.

Here is an example of an endpoint documentation: Get realtime weather.

Most REST API documentation is organized into the same key sections:

1. Basic Info

1.Endpoint Title & Description

[Get realtime weather](/docs/get-realtime-weather-24838732e0)

Realtime weather API method allows a user to get up to date current weather information in JSON.

This tells you:

What the endpoint does → returns current weather

Format → JSON

Use case → get the latest available data for a location

2. HTTP Method

The most common HTTP methods include:

Method	Meaning	Typical Usage
GET	Retrieve data	Fetch a weather report
POST	Create data	Create a user or submit a form
PUT	Replace existing data	Update a full resource
PATCH	Partially update	Update one field
DELETE	Remove	Delete an item

In our example, the method is GET.

3. Endpoint URL

Example:

http://api.weatherapi.com/v1/current.json

This is the base URL you will send the request to.

2. Request

This describes the request part that you send to the server.

1. Parameters

Most GET endpoints use query parameters.
Other APIs may also include:

Type	Where it Appears	Example Purpose
Query Params	After `?` in URL	Filters, pagination
Path Params	Inside the URL	`/user/{id}`
Headers	Separate section	Authentication tokens
Body Params	Request body	JSON sent when POSTing

In WeatherAPI’s example, there a three query params in the URL, which appears after '?' and are divided by '&'.

http://api.weatherapi.com/v1/current.json?key=3432a351afd04b30bef75833252711&q=New%20York&aqi=no

Name	Required	Type	Purpose
`key`	required	string	API key
`q`	required	string	Location
`aqi`	optional	string	Include air quality

If an API has more parameters, docs will usually allow extending the URL:

?limit=20&offset=40&sort=created

2. Request Body (if applicable)

For GET requests: usually no body.
For POST/PUT/PATCH: the body can be:

JSON (most common)

Form data

XML

Multipart (e.g., file upload)

Example JSON body (not from WeatherAPI):

{
  "title": "Hello",
  "content": "This is a post"
}

3. Example Request (Helpful but Not Mandatory)

Examples help you verify that the format you send is correct.

3. Response

This part describes what the server return to you.

1. HTTP code

When you look at an API’s response section, one of the first things you'll see is the HTTP status code.

Status codes tell you whether the request succeeded or failed. They are universal across almost all REST APIs.

In WeatherAPI’s response spec, the primary success example is:

🟢 200 OK

200 OK means your request succeeded. Whether you're fetching weather data, user info, or product lists—successful reads almost always return 200.

Good API docs also include other HTTP codes:

Status	Meaning
400	Bad request
401	Unauthorized
404	Not found
500	Server error

2. Response Specification

This is one of the most important parts.

It explains:

what fields you will receive

each field’s data type

its meaning

whether it is required

Example snippet:

location (object)
  name: string (required)  — Name of the location
  region: string (required)
  country: string (required)
  lat: number (required)
  lon: number (required)

This tells you:

The response includes a top-level field location

Inside it are required fields such as name, lat, lon

You’ll use this information to parse the response.

3. Example Response (Very Useful)

{
  "location": { ... },
  "current": { ... }
}

An example response shows you the actual shape and helps you confirm your code or API tool (like Apidog) is working.

4. Key Takeaways

Once you understand these core sections—method, URL, parameters, request body, status codes, and response structure—API documentation becomes far less intimidating. Almost all REST APIs follow this same pattern, so the skills you learn here apply everywhere.

With this foundation, you can confidently read any API documentation, build correct requests, and interpret the responses you receive. From here, you can start experimenting with real APIs in tools like Apidog and gradually move on to more advanced concepts such as authentication, pagination, and error handling.

You’ve now taken the first major step toward becoming comfortable and productive with APIs.

Now you’ve learned the basics of how to read API documentation. Let's wrap up this chapter with a Chapter Summary before diving into API fundamentals.

How to Read an API Documentation?

1. Basic Info#

1.Endpoint Title & Description#

2. HTTP Method#

3. Endpoint URL#

2. Request#

1. Parameters#

2. Request Body (if applicable)#

3. Example Request (Helpful but Not Mandatory)#

3. Response#

1. HTTP code#

2. Response Specification#

3. Example Response (Very Useful)#

4. Key Takeaways#