Python feature flags installation

Install the package

Required

Install the PostHog Python library using pip:

Terminal
pip install posthog

Initialize PostHog

Required

Initialize the PostHog client with your project API key and host from your project settings:

Python
from posthog import Posthog

posthog = Posthog(
    project_api_key='<ph_project_api_key>',
    host='https://us.i.posthog.com'
)

Django integration

If you're using Django, check out our Django integration for automatic request tracking.

3
Send events
Recommended
Once installed, PostHog will automatically start capturing events. You can also manually send events to test your integration:
Capture custom events by calling the capture method with an event name and properties:
Python
import posthog posthog.capture('user_123', 'user_signed_up', properties={'example_property': 'example_value'})
By default, for backwards compatibility reasons, events are sent with person profile processing enabled. This means a person profile will be created for each user who triggers an event.
If you want to disable person profile processing for certain events, send the event with the following property:
Python
"$process_person_profile": False

Evaluate boolean feature flags

Required

Check if a feature flag is enabled:

is_my_flag_enabled = posthog.feature_enabled('flag-key', 'distinct_id_of_your_user')
if is_my_flag_enabled:
    # Do something differently for this user
    # Optional: fetch the payload
    matched_flag_payload = posthog.get_feature_flag_payload('flag-key', 'distinct_id_of_your_user')

Evaluate multivariate feature flags

Optional

For multivariate flags, check which variant the user has been assigned:

enabled_variant = posthog.get_feature_flag('flag-key', 'distinct_id_of_your_user')
if enabled_variant == 'variant-key': # replace 'variant-key' with the key of your variant
    # Do something differently for this user
    # Optional: fetch the payload
    matched_flag_payload = posthog.get_feature_flag_payload('flag-key', 'distinct_id_of_your_user')

Include feature flag information in events

Required

If you want to use your feature flag to breakdown or filter events in your insights, you'll need to include feature flag information in those events. This ensures that the feature flag value is attributed correctly to the event.

Note: This step is only required for events captured using our server-side SDKs or API.

Set send_feature_flags to True in your capture call:

Python
posthog.capture(
    distinct_id="distinct_id_of_the_user",
    event='event_name',
    send_feature_flags=True
)

Include the $feature/feature_flag_name property in your event properties:

Python
posthog.capture(
    "event_name",
    distinct_id="distinct_id_of_the_user",
    properties={
        "$feature/feature-flag-key": "variant-key"  # replace feature-flag-key with your flag key. Replace 'variant-key' with the key of your variant
    },
)

Override server properties

Optional

Sometimes, you may want to evaluate feature flags using properties that haven't been ingested yet, or were set incorrectly earlier. You can provide properties to evaluate the flag with:

posthog.get_feature_flag(
    'flag-key',
    'distinct_id_of_the_user',
    person_properties={'property_name': 'value'},
    groups={
        'your_group_type': 'your_group_id',
        'another_group_type': 'your_group_id'},
    group_properties={
        'your_group_type': {'group_property_name': 'value'},
        'another_group_type': {'group_property_name': 'value'}
    },
)

8
Running experiments
Optional
Experiments run on top of our feature flags. Once you've implemented the flag in your code, you run an experiment by creating a new experiment in the PostHog dashboard.

Next steps

Recommended

Resource	Description
Creating a feature flag	How to create a feature flag in PostHog
Adding feature flag code	How to check flags in your code for all platforms
Framework-specific guides	Setup guides for React Native, Next.js, Flutter, and other frameworks
How to do a phased rollout	Gradually roll out features to minimize risk
More tutorials	Other real-world examples and use cases

Python feature flags installation

Install the package

Initialize PostHog

Send events

Evaluate boolean feature flags

Evaluate multivariate feature flags

Include feature flag information in events

Override server properties

Running experiments

Next steps

Community questions

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