ImportError: cannot import name 'jsonify' from 'flask'

ImportError: cannot import name ‘jsonify’ from ‘flask’

$ python -c "from flask import jsonify"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ImportError: cannot import name 'jsonify' from 'flask' (unknown location)

Why this happens

This error typically appears due to one of these reasons:

• A circular import: importing jsonify inside a module that Flask imports during app creation, causing partial module initialization.
• Shadowing the flask package: a local file or folder named flask.py or flask/ takes precedence over the installed package.
• Broken/incorrect environment: Flask isn’t installed in the active environment, or multiple Python interpreters are in use.
• Wrong import target: importing from a submodule that doesn’t expose jsonify.

Fix

• Ensure Flask is installed and you’re using the intended Python environment.
• Remove or rename any local flask.py or flask/ directories to avoid shadowing.
• Avoid circular imports by moving imports to the top-level or refactoring app structure.
• Import jsonify directly from flask in your route modules and avoid importing your app in those modules.

Wrong code

# app/routes.py
from app import app  # This can trigger circular imports if app imports routes
from flask import jsonify

@app.route('/ping')
def ping():
    return jsonify({"status": "ok"})

Fixed code

# app/__init__.py
from flask import Flask

app = Flask(__name__)

from . import routes  # Import routes after app is created

# app/routes.py
from flask import jsonify
from . import app

@app.route('/ping')
def ping():
    return jsonify({"status": "ok"})

By deferring the import of routes until after app is created, you avoid the circular dependency that leads to the ImportError. Also confirm that no local flask.py file shadows the package and that your virtual environment is active.