ImportError: cannot import name 'JSONEncoder' from 'flask.json'

[D3vil0p3r]

When I run faraday-server I get:

Traceback (most recent call last):
  File "/usr/bin/faraday-server", line 33, in <module>
    sys.exit(load_entry_point('faradaysec==5.7.0', 'console_scripts', 'faraday-server')())
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/bin/faraday-server", line 25, in importlib_load_entry_point
    return next(matches).load()
           ^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/importlib/metadata/__init__.py", line 205, in load
    module = import_module(match.group('module'))
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/importlib/__init__.py", line 90, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 995, in exec_module
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "/usr/lib/python3.12/site-packages/faraday/start_server.py", line 25, in <module>
    from faraday.server.app import get_app
  File "/usr/lib/python3.12/site-packages/faraday/server/app.py", line 32, in <module>
    from flask.json import JSONEncoder
ImportError: cannot import name 'JSONEncoder' from 'flask.json' (/usr/lib/python3.12/site-packages/flask/json/__init__.py)

despite I installed all the mentioned dependencies in requirements.txt.

[ezk06eer]

Hello @D3vil0p3r can you please show us /usr/lib/python3.12/site-packages/ contents?

It seems you're using python 3.12

Thanks!

[D3vil0p3r]

Hello @D3vil0p3r can you please show us /usr/lib/python3.12/site-packages/ contents?

It seems you're using python 3.12

Thanks!

@ezk06eer Now I am using Python 3.13 and still getting:

faraday-server
Traceback (most recent call last):
  File "/usr/bin/faraday-server", line 33, in <module>
    sys.exit(load_entry_point('faradaysec==5.16.0', 'console_scripts', 'faraday-server')())
             ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/bin/faraday-server", line 25, in importlib_load_entry_point
    return next(matches).load()
           ~~~~~~~~~~~~~~~~~~^^
  File "/usr/lib/python3.13/importlib/metadata/__init__.py", line 179, in load
    module = import_module(match.group('module'))
  File "/usr/lib/python3.13/importlib/__init__.py", line 88, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 1026, in exec_module
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "/usr/lib/python3.13/site-packages/faraday/start_server.py", line 25, in <module>
    from faraday.server.app import get_app, create_app
  File "/usr/lib/python3.13/site-packages/faraday/server/app.py", line 34, in <module>
    from flask.json import JSONEncoder
ImportError: cannot import name 'JSONEncoder' from 'flask.json' (/usr/lib/python3.13/site-packages/flask/json/__init__.py)

[D3vil0p3r]

I guess JSONEncoder from flask is deprecated MongoEngine/flask-mongoengine#522 and https://www.reddit.com/r/flask/comments/1869xe9/overriding_json_encoder_in_flask_30_json_encoder/

Could you please use a maintained library for JSON encoding?

[ignaciosoto93]

Thanks for the detailed report and follow-up, @D3vil0p3r .

Based on your traceback, Faraday is installed system-wide (/usr/lib/python3.12/site-packages/), which is causing Flask version conflicts.

Fix: Use an isolated virtual environment:

python3 -m venv faraday_venv
source faraday_venv/bin/activate
pip3 install faradaysec
faraday-manage initdb

Why this happens: Your system has Flask 3.x, which removed JSONEncoder from flask.json. Faraday requires Flask <=2.1.3. A virtualenv ensures the correct versions are isolated from system packages.

[D3vil0p3r]

Thank you for the answer. I am installing system-wide because I am packaging Faraday for BlackArch.

[ignaciosoto93]

Thanks for clarifying, @D3vil0p3r .

As a BlackArch package maintainer, system-wide installation with Arch's Flask 3.x is a valid requirement. This is not a user configuration issue — Faraday needs to update its dependencies.

Keeping this open to track Flask 3.x compatibility.