HAL format overview in Rest API

Introduction

HAL helps organize data and links in APIs so computers and people can understand and use them easily.

When building APIs that need to show related information and links clearly.

When you want clients to discover more data by following links automatically.

When you want a simple, standard way to format API responses with data and navigation.

When you want to make your API easier to use and understand without extra documentation.

Syntax

Rest API

{
  "_links": {
    "self": { "href": "/orders/123" },
    "next": { "href": "/orders/124" }
  },
  "property": "value"
}

"_links" holds URLs related to the current data.

Each link has a "href" showing where it points.

Examples

Shows a user with a link to itself.

Rest API

{
  "_links": {
    "self": { "href": "/users/1" }
  },
  "name": "Alice"
}

Shows a book with a link to its author.

Rest API

{
  "_links": {
    "self": { "href": "/books/42" },
    "author": { "href": "/authors/7" }
  },
  "title": "Learn HAL"
}

Sample Program

This is a simple HAL response for a product with links to itself and its reviews.

Rest API

{
  "_links": {
    "self": { "href": "/products/100" },
    "reviews": { "href": "/products/100/reviews" }
  },
  "id": 100,
  "name": "Coffee Mug",
  "price": 12.99
}

Important Notes

HAL uses JSON format with special "_links" and optionally "_embedded" sections.

Links help clients navigate the API without guessing URLs.

It keeps API responses consistent and easy to understand.

Summary

HAL organizes API data with links in a simple JSON format.

It helps clients find related information easily.

Using HAL makes APIs more user-friendly and discoverable.