Put vs patch difference

Rest-apiComparisonBeginner · 4 min read

PUT vs PATCH: Key Differences and When to Use Each

The PUT method replaces an entire resource with the data sent, while PATCH updates only specific fields of a resource. PUT is idempotent and expects full data, whereas PATCH is used for partial updates and may be idempotent depending on implementation.

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Quick Comparison

Here is a quick side-by-side comparison of PUT and PATCH methods in REST APIs.

Factor	PUT	PATCH
Purpose	Replace entire resource	Update part of the resource
Request Body	Full resource representation	Partial resource data
Idempotency	Yes (same request repeated has same effect)	May be idempotent depending on implementation
Use Case	Complete update or create resource	Partial update
Effect on Missing Fields	Missing fields are removed	Missing fields remain unchanged
Typical Response	200 OK or 204 No Content	200 OK or 204 No Content

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Key Differences

The PUT method is designed to replace the entire resource at the specified URL. When you send a PUT request, you provide the full new state of the resource. If some fields are missing in the request, they are usually removed or reset on the server. This makes PUT idempotent, meaning sending the same request multiple times results in the same resource state.

On the other hand, PATCH is used to make partial updates to a resource. You only send the fields you want to change, and the server updates those fields without affecting others. Because PATCH modifies parts of the resource, it may be idempotent depending on the implementation. This makes PATCH more efficient when you want to update a few fields without resending the entire resource.

In summary, use PUT when you want to replace or create a resource fully, and use PATCH when you want to update only specific parts of a resource.

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PUT Code Example

This example shows how to update a user resource fully using PUT. The entire user data is sent in the request.

python

import requests

url = 'https://api.example.com/users/123'

user_data = {
    'name': 'Alice Smith',
    'email': 'alice@example.com',
    'age': 30
}

response = requests.put(url, json=user_data)
print(response.status_code)
print(response.json())

Output

200 {"id":123,"name":"Alice Smith","email":"alice@example.com","age":30}

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PATCH Equivalent

This example updates only the email field of the user using PATCH. Other fields remain unchanged.

python

import requests

url = 'https://api.example.com/users/123'

partial_update = {
    'email': 'alice.new@example.com'
}

response = requests.patch(url, json=partial_update)
print(response.status_code)
print(response.json())

Output

200 {"id":123,"name":"Alice Smith","email":"alice.new@example.com","age":30}

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When to Use Which

Choose PUT when: You want to replace the entire resource or create it if it does not exist. This is useful when you have the full updated data and want to ensure the resource matches exactly.

Choose PATCH when: You want to update only certain fields without affecting the rest of the resource. This is efficient for small changes and avoids sending unnecessary data.

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Key Takeaways

PUT replaces the entire resource and requires full data in the request.

PATCH updates only specified fields and is used for partial updates.

PUT is idempotent; PATCH may be idempotent depending on implementation.

Use PUT for complete resource replacement or creation.

Use PATCH for efficient partial updates without affecting other fields.