python data_error ai_generated true

werkzeug.exceptions.BadRequest: 400 Bad Request: Failed to decode JSON object: Expecting value: line 1 column 1 (char 0)

ID: python/flask-json-request-invalid

Also available as: JSON · Markdown · 中文
80%Fix Rate
89%Confidence
0Evidence
2025-06-30First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
3.x active — — —

Root Cause

The request body is not valid JSON when Flask tries to parse it via request.get_json().

generic

中文

当 Flask 尝试通过 request.get_json() 解析时，请求体不是有效的 JSON。

Workarounds

  1. 95% success 
    Validate first: if request.is_json: data = request.get_json() else: return {'error': 'Invalid JSON'}, 400
  2. 90% success 
    Use request.get_json(silent=True) which returns None on error and handle it

Dead Ends

Common approaches that don't work:

  1. 70% fail

    Still raises JSONDecodeError if the body is invalid.

  2. 40% fail

    This doesn't help the client fix their request; they need to send valid JSON.