Partial success handling in Rest API

Introduction

Partial success handling helps your app tell which parts of a request worked and which parts did not. This way, users know exactly what happened without guessing.

When uploading multiple files and some succeed but others fail.

When updating several records and only some updates apply.

When sending batch requests where some actions complete and others don't.

When processing a list of tasks and some finish while others error.

Syntax

Rest API

HTTP/1.1 207 Multi-Status
Content-Type: application/json

{
  "results": [
    {"id": 1, "status": "success"},
    {"id": 2, "status": "error", "message": "Invalid data"}
  ]
}

The HTTP status code 207 Multi-Status is often used to show partial success.

The response body usually contains details about each item's result.

Examples

This example shows two files: one uploaded successfully, the other failed with an error message.

Rest API

HTTP/1.1 207 Multi-Status
Content-Type: application/json

{
  "results": [
    {"file": "image1.png", "status": "uploaded"},
    {"file": "image2.png", "status": "failed", "error": "File too large"}
  ]
}

Here, two tasks are processed: one finished, the other failed due to timeout.

Rest API

HTTP/1.1 207 Multi-Status
Content-Type: application/json

{
  "tasks": [
    {"taskId": 101, "status": "completed"},
    {"taskId": 102, "status": "failed", "reason": "Timeout"}
  ]
}

Sample Program

This simple Flask app accepts a list of file names. It marks files with names shorter than 10 characters as uploaded, others as failed. It returns a 207 status with details.

Rest API

from flask import Flask, jsonify, request

app = Flask(__name__)

@app.route('/upload', methods=['POST'])
def upload_files():
    files = request.json.get('files', [])
    results = []
    for f in files:
        if len(f) < 10:
            results.append({'file': f, 'status': 'uploaded'})
        else:
            results.append({'file': f, 'status': 'failed', 'error': 'File name too long'})
    return jsonify({'results': results}), 207

if __name__ == '__main__':
    app.run(debug=True)

Important Notes

Use HTTP status 207 to clearly indicate partial success.

Always include detailed info in the response body so clients know what succeeded or failed.

Partial success helps avoid confusion and improves user experience.

Summary

Partial success handling tells which parts of a request worked and which did not.

Use HTTP 207 Multi-Status with detailed JSON results.

This approach helps users understand exactly what happened.

Practice

1. What does HTTP 207 Multi-Status indicate in REST API partial success handling?

easy

A. Some parts of the request succeeded while others failed

B. The entire request failed due to server error

C. The request was redirected to another URL

D. The request was successful with no errors

Solution

1. Step 1: Understand HTTP 207 Multi-Status meaning

   HTTP 207 is used to report multiple status codes for different parts of a single request.

2. Step 2: Relate to partial success handling

   This status code indicates that some parts succeeded and others failed, providing detailed results.

3. Final Answer:

   Some parts of the request succeeded while others failed -> Option A

4. Quick Check:

   HTTP 207 = Partial success [OK]

Hint: 207 means mixed results, not full success or failure [OK]

Common Mistakes:

• Confusing 207 with 200 OK
• Thinking 207 means full failure
• Assuming 207 is a redirect status

2. Which of the following is the correct way to represent partial success in a REST API response?

easy

A. HTTP 404 with error message

B. HTTP 200 with empty body

C. HTTP 207 with JSON detailing success and failure

D. HTTP 500 with stack trace

Solution

1. Step 1: Identify correct HTTP status for partial success

   HTTP 207 Multi-Status is designed to show multiple results in one response.

2. Step 2: Confirm response format

   Using JSON to detail which parts succeeded or failed is the standard approach.

3. Final Answer:

   HTTP 207 with JSON detailing success and failure -> Option C

4. Quick Check:

   207 + JSON = Partial success response [OK]

Hint: Use 207 with JSON for partial success, not 200 or errors [OK]

Common Mistakes:

• Using 200 OK without details
• Returning 404 for partial success
• Sending server error 500 instead of partial status

3. Given this partial success JSON response, what is the status of item with ID 3?

{
  "responses": [
    {"id": 1, "status": "success"},
    {"id": 2, "status": "failure", "error": "Invalid data"},
    {"id": 3, "status": "success"}
  ]
}

medium

A. Failure due to invalid data

B. Success

C. Unknown status

D. Pending

Solution

1. Step 1: Locate item with ID 3 in JSON

   Item with ID 3 has "status": "success" in the responses array.

2. Step 2: Interpret the status value

   The status "success" means the operation for item 3 succeeded.

3. Final Answer:

   Success -> Option B

4. Quick Check:

   ID 3 status = success [OK]

Hint: Check the status field for the item ID in JSON [OK]

Common Mistakes:

• Confusing failure of other items with this one
• Assuming missing error means failure
• Ignoring the status field

4. You receive this HTTP response code and body from a batch update API:

HTTP/1.1 207 Multi-Status
{
  "results": [
    {"item": "A", "status": "success"},
    {"item": "B", "status": "fail", "error": "Timeout"}
  ]
}

What is the main issue in this response?

medium

A. Incorrect HTTP status code for partial success

B. JSON format is invalid

C. Missing Content-Type header

D. The status value "fail" should be "failure" or "error"

Solution

1. Step 1: Check HTTP status code usage

   HTTP 207 Multi-Status is correct for partial success.

2. Step 2: Verify status field values

   Common practice uses "success" and "failure" or "error"; "fail" is inconsistent and may cause confusion.

3. Final Answer:

   The status value "fail" should be "failure" or "error" -> Option D

4. Quick Check:

   Status values must be consistent and clear [OK]

Hint: Use standard status words like 'success' and 'failure' [OK]

Common Mistakes:

• Thinking 207 is wrong here
• Ignoring inconsistent status wording
• Assuming JSON is invalid without checking

5. You design a REST API endpoint that processes a list of user updates. Some updates succeed, others fail due to validation errors. How should you structure the response to clearly communicate partial success?

hard

A. Return HTTP 207 with a JSON array showing each user's update status and error if any

B. Return HTTP 400 with a generic error message for all failures

C. Return HTTP 200 with a simple success message ignoring failures

D. Return HTTP 500 with server error details

Solution

1. Step 1: Identify the need for partial success reporting

   Since some updates succeed and others fail, the response must show both results clearly.

2. Step 2: Choose appropriate HTTP status and response format

   HTTP 207 Multi-Status with detailed JSON per user update is the best practice to communicate partial success.

3. Final Answer:

   Return HTTP 207 with a JSON array showing each user's update status and error if any -> Option A

4. Quick Check:

   207 + detailed JSON = clear partial success [OK]

Hint: Use 207 and detailed JSON for mixed success/failure results [OK]

Common Mistakes:

• Ignoring failed updates in response
• Using 200 OK without details
• Returning generic errors instead of per-item status