Why Composite operations (multi-resource) in Rest API? - Purpose & Use Cases

The Big Idea

What if you could update many things at once with just one simple API call?

The Scenario

Imagine you need to update a user's profile and their related settings by calling separate API endpoints one by one.

You have to send multiple requests manually, waiting for each to finish before starting the next.

The Problem

This manual approach is slow because each request waits for the previous one.

It's also error-prone: if one request fails, you might end up with inconsistent data.

Handling all these steps manually makes your code complex and hard to maintain.

The Solution

Composite operations let you bundle multiple API calls into a single request.

This means you can update the user profile and settings together, atomically.

The server handles all steps, ensuring consistency and faster execution.

Before vs After

✗ Before

PATCH /user/123
PATCH /user/123/settings

✓ After

POST /composite
{
  "operations": [
    {"method": "PATCH", "path": "/user/123", "body": {...}},
    {"method": "PATCH", "path": "/user/123/settings", "body": {...}}
  ]
}

What It Enables

Composite operations enable you to perform multiple related changes in one go, making your app faster and more reliable.

Real Life Example

When a user updates their profile and notification preferences, a composite operation updates both at once, avoiding partial updates that confuse the user.

Key Takeaways

Manual multiple API calls are slow and risky.

Composite operations bundle calls into one request.

This improves speed, consistency, and code simplicity.