Hey there! Let's work through this error you're hitting—totally understandable when you're just getting started with Python and REST APIs. Here are the most common fixes to try:

1. First, Check if Your File Actually Contains Valid JSON #

The error usually means the content in your output file isn't proper JSON. Let's confirm that first:

• Open the file manually in a text editor and glance at it. Do you see things like HTML error messages (e.g., "404 Not Found", "500 Internal Server Error") or random text instead of curly braces {}/brackets []?
• If you want to check it in Python, run this quick snippet to print the file content:

  with open('your_output_file.json', 'r') as f:
      file_content = f.read()
      print("File content:", file_content)
  

  Look for any obvious issues—like missing commas, extra quotes, or non-JSON text from a failed API request.

2. Verify Your REST API Request Was Successful #

Chances are, your GET request didn't return a valid JSON response at all. APIs often send non-JSON error messages when something goes wrong (like authentication failures, invalid endpoints). Add checks to your API request code to catch this early:

import requests

# Replace with your actual API URL
api_url = "https://your-api-endpoint.com/data"
response = requests.get(api_url)

# First, check if the request succeeded (status code 200 means OK)
if response.status_code == 200:
    # Only save the content if we get a valid success response
    with open('output.json', 'w') as f:
        f.write(response.text)
else:
    print(f"API Request Failed! Status Code: {response.status_code}")
    print(f"Error Content: {response.text}")

This way, you'll immediately know if the API is sending back an error instead of JSON.

3. Use json.load() Instead of json.loads() (Simpler & Safer) #

Instead of reading the file into a string first and using json.loads(), you can let json.load() handle reading the file directly—it avoids small issues with encoding or extra whitespace:

import json

try:
    with open('your_output_file.json', 'r', encoding='utf-8') as f:
        data = json.load(f)  # Directly load from the file object
    print("Success! Parsed data:", data)
except ValueError as e:
    print(f"Failed to parse JSON: {e}")

Adding encoding='utf-8' also helps avoid issues with special characters in the JSON.

4. Check for Empty or Incomplete Files #

If your file is empty (maybe the API returned nothing) or only partially written, json.loads() will fail. Add a quick check for empty content:

import json

with open('your_output_file.json', 'r') as f:
    content = f.read().strip()  # Remove extra whitespace/newlines
    if not content:
        print("Error: The file is empty!")
    else:
        try:
            data = json.loads(content)
        except ValueError as e:
            print(f"Invalid JSON: {e}")
            print(f"Problematic content: {content}")

Start with these steps—most of the time, the issue is either a failed API request returning non-JSON, or a typo/invalid content in the file. Let me know if you find something specific in your file or API response!

内容的提问来源于stack exchange，提问作者Manu SS nair