PostHog Python SDK

SDK Version: 6.0.3

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PostHog

This is the SDK reference for the PostHog Python SDK. You can learn more about example usage in the Python SDK documentation. You can also follow Flask and Django guides to integrate PostHog into your project.

Initialization methods

Clientpublic

Initialize a new PostHog client instance.

Parameters

NameType
project_api_key?str

The project API key.

hostany

The host to use for the client.

debugbool

Whether to enable debug mode.

max_queue_sizeint

Parameter: max_queue_size

sendbool

Parameter: send

on_errorany

Parameter: on_error

flush_atint

Parameter: flush_at

flush_intervalfloat

Parameter: flush_interval

gzipbool

Parameter: gzip

max_retriesint

Parameter: max_retries

sync_modebool

Parameter: sync_mode

timeoutint

Parameter: timeout

threadint

Parameter: thread

poll_intervalint

Parameter: poll_interval

personal_api_keyany

Parameter: personal_api_key

disabledbool

Parameter: disabled

disable_geoipbool

Parameter: disable_geoip

historical_migrationbool

Parameter: historical_migration

feature_flags_request_timeout_secondsint

Parameter: feature_flags_request_timeout_seconds

super_propertiesany

Parameter: super_properties

enable_exception_autocapturebool

Parameter: enable_exception_autocapture

log_captured_exceptionsbool

Parameter: log_captured_exceptions

project_rootany

Parameter: project_root

privacy_modebool

Parameter: privacy_mode

before_sendany

Parameter: before_send

flag_fallback_cache_urlany

Parameter: flag_fallback_cache_url

Examples

Python
from posthog import Posthog
posthog = Posthog('<ph_project_api_key>', host='<ph_app_host>')

Returns

Type
None

Capture methods

capturepublic

Captures an event manually. Learn about capture best practices

Parameters

NameType
event?str

The event name to capture.

kwargs?typing_extensions.Unpack[OptionalCaptureArgs]

Parameter: kwargs

Examples

Python
# Anonymous event
posthog.capture('some-anon-event')

Returns

Type
Optional[str]

Contexts methods

new_contextpublic

Create a new context for managing shared state. Learn more about contexts.

Parameters

NameType
freshbool

Whether to create a fresh context that doesn't inherit from parent.

capture_exceptionsbool

Whether to automatically capture exceptions in this context.

Examples

Python
with posthog.new_context():
identify_context('<distinct_id>')
posthog.capture('event_name')

Returns

Type
None

Error Tracking methods

capture_exceptionpublic

Capture an exception for error tracking.

Parameters

NameType
exception?BaseException

The exception to capture.

kwargs?typing_extensions.Unpack[OptionalCaptureArgs]

Parameter: kwargs

Examples

Python
try:
# Some code that might fail
pass
except Exception as e:
posthog.capture_exception(e, 'user_distinct_id', properties=additional_properties)

Returns

Type
None

Feature Flags methods

feature_enabledpublic

Check if a feature flag is enabled for a user.

Parameters

NameType
key?any

The feature flag key.

distinct_id?any

The distinct ID of the user.

groupsdict

A dictionary of group information.

person_propertiesdict

A dictionary of person properties.

group_propertiesdict

A dictionary of group properties.

only_evaluate_locallybool

Whether to only evaluate locally.

send_feature_flag_eventsbool

Whether to send feature flag events.

disable_geoipany

Whether to disable GeoIP for this request.

Examples

Python
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')

Returns

Type
None

get_all_flagspublic

Get all feature flags for a user.

Parameters

NameType
distinct_id?any

The distinct ID of the user.

groupsdict

A dictionary of group information.

person_propertiesdict

A dictionary of person properties.

group_propertiesdict

A dictionary of group properties.

only_evaluate_locallybool

Whether to only evaluate locally.

disable_geoipany

Whether to disable GeoIP for this request.

Examples

Python
posthog.get_all_flags('distinct_id_of_your_user')

Returns

Type
Optional[dict[str, Union[bool, str]]]

get_all_flags_and_payloadspublic

Get all feature flags and their payloads for a user.

Parameters

NameType
distinct_id?any

The distinct ID of the user.

groupsdict

A dictionary of group information.

person_propertiesdict

A dictionary of person properties.

group_propertiesdict

A dictionary of group properties.

only_evaluate_locallybool

Whether to only evaluate locally.

disable_geoipany

Whether to disable GeoIP for this request.

Examples

Python
posthog.get_all_flags_and_payloads('distinct_id_of_your_user')

Returns

get_feature_flagpublic

Get multivariate feature flag value for a user.

Parameters

NameType
key?any

The feature flag key.

distinct_id?any

The distinct ID of the user.

groupsdict

A dictionary of group information.

person_propertiesdict

A dictionary of person properties.

group_propertiesdict

A dictionary of group properties.

only_evaluate_locallybool

Whether to only evaluate locally.

send_feature_flag_eventsbool

Whether to send feature flag events.

disable_geoipany

Whether to disable GeoIP for this request.

Examples

Python
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')

Returns

Type
Union[bool, str, any]

get_feature_flag_payloadpublic

Get the payload for a feature flag.

Parameters

NameType
key?any

The feature flag key.

distinct_id?any

The distinct ID of the user.

match_valuebool

The specific flag value to get payload for.

groupsdict

A dictionary of group information.

person_propertiesdict

A dictionary of person properties.

group_propertiesdict

A dictionary of group properties.

only_evaluate_locallybool

Whether to only evaluate locally.

send_feature_flag_eventsbool

Whether to send feature flag events.

disable_geoipany

Whether to disable GeoIP for this request.

Examples

Python
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')

Returns

Type
None

get_feature_flags_and_payloadspublic

Get feature flags and payloads for a user by calling decide.

Parameters

NameType
distinct_id?any

The distinct ID of the user.

groupsany

A dictionary of group information.

person_propertiesany

A dictionary of person properties.

group_propertiesany

A dictionary of group properties.

disable_geoipany

Whether to disable GeoIP for this request.

Examples

Python
result = posthog.get_feature_flags_and_payloads('<distinct_id>')

Returns

get_feature_payloadspublic

Get feature flag payloads for a user by calling decide.

Parameters

NameType
distinct_id?any

The distinct ID of the user.

groupsany

A dictionary of group information.

person_propertiesany

A dictionary of person properties.

group_propertiesany

A dictionary of group properties.

disable_geoipany

Whether to disable GeoIP for this request.

Examples

Python
payloads = posthog.get_feature_payloads('<distinct_id>')

Returns

Type
dict[str, str]

get_feature_variantspublic

Get feature flag variants for a user by calling decide.

Parameters

NameType
distinct_id?any

The distinct ID of the user.

groupsany

A dictionary of group information.

person_propertiesany

A dictionary of person properties.

group_propertiesany

A dictionary of group properties.

disable_geoipany

Whether to disable GeoIP for this request.

Returns

Type
dict[str, Union[bool, str]]

get_flags_decisionpublic

Get feature flags decision.

Parameters

NameType
distinct_idNumber

The distinct ID of the user.

groups?dict

A dictionary of group information.

person_propertiesany

A dictionary of person properties.

group_propertiesany

A dictionary of group properties.

disable_geoipany

Whether to disable GeoIP for this request.

Examples

Python
decision = posthog.get_flags_decision('user123')

Returns

load_feature_flagspublic

Load feature flags for local evaluation.

Examples

Python
posthog.load_feature_flags()

Returns

Type
None

Identification methods

aliaspublic

Create an alias between two distinct IDs.

Parameters

NameType
previous_id?str

The previous distinct ID.

distinct_id?str

The new distinct ID to alias to.

timestampany

The timestamp of the event.

uuidany

A unique identifier for the event.

disable_geoipany

Whether to disable GeoIP for this event.

Examples

Python
posthog.alias(previous_id='distinct_id', distinct_id='alias_id')

Returns

Type
None

group_identifypublic

Identify a group and set its properties.

Parameters

NameType
group_type?str

The type of group (e.g., 'company', 'team').

group_key?str

The unique identifier for the group.

propertiesany

A dictionary of properties to set on the group.

timestampany

The timestamp of the event.

uuidany

A unique identifier for the event.

disable_geoipany

Whether to disable GeoIP for this event.

distinct_idany

The distinct ID of the user performing the action.

Examples

Python
posthog.group_identify('company', 'company_id_in_your_db', {
'name': 'Awesome Inc.',
'employees': 11
})

Returns

Type
None

setpublic

Set properties on a person profile.

Parameters

NameType
kwargs?typing_extensions.Unpack[OptionalSetArgs]

Parameter: kwargs

Examples

Python
# Set with distinct id
posthog.capture(
'event_name',
distinct_id='user-distinct-id',
properties={
'$set': {'name': 'Max Hedgehog'},
'$set_once': {'initial_url': '/blog'}
}
)

Returns

Type
Optional[str]

set_oncepublic

Set properties on a person profile only if they haven't been set before.

Parameters

NameType
kwargs?typing_extensions.Unpack[OptionalSetArgs]

Parameter: kwargs

Examples

Python
posthog.set_once(distinct_id='user123', properties={'initial_signup_date': '2024-01-01'})

Returns

Type
Optional[str]

Other methods

flushpublic

Force a flush from the internal queue to the server. Do not use directly, call shutdown() instead.

Examples

Python
posthog.capture('event_name')
posthog.flush() # Ensures the event is sent immediately

Returns

Type
None

get_feature_flag_resultpublic

Get a FeatureFlagResult object which contains the flag result and payload for a key by evaluating locally or remotely depending on whether local evaluation is enabled and the flag can be locally evaluated. This also captures the $feature_flag_called event unless send_feature_flag_events is False.

Parameters

NameType
key?any

The feature flag key.

distinct_id?any

The distinct ID of the user.

groupsdict

A dictionary of group information.

person_propertiesdict

A dictionary of person properties.

group_propertiesdict

A dictionary of group properties.

only_evaluate_locallybool

Whether to only evaluate locally.

send_feature_flag_eventsbool

Whether to send feature flag events.

disable_geoipany

Whether to disable GeoIP for this request.

Examples

Python
flag_result = posthog.get_feature_flag_result('flag-key', 'distinct_id_of_your_user')
if flag_result and flag_result.get_value() == 'variant-key':
# Do something differently for this user
# Optional: fetch the payload
matched_flag_payload = flag_result.payload

Returns

Type
Optional[FeatureFlagResult]

joinpublic

End the consumer thread once the queue is empty. Do not use directly, call shutdown() instead.

Examples

Python
posthog.join()

Returns

Type
None

shutdownpublic

Flush all messages and cleanly shutdown the client. Call this before the process ends in serverless environments to avoid data loss.

Examples

Python
posthog.shutdown()

Returns

Type
None

PostHog Module Functions

Global functions available in the PostHog module

Client management methods

flushpublic

Tell the client to flush.

Examples

Python
from posthog import flush
flush()

Returns

Type
None

joinpublic

Block program until the client clears the queue.

Examples

Python
from posthog import join
join()

Returns

Type
None

shutdownpublic

Flush all messages and cleanly shutdown the client.

Examples

Python
from posthog import shutdown
shutdown()

Returns

Type
None

Contexts methods

new_contextpublic

Create a new context scope that will be active for the duration of the with block.

Parameters

NameType
freshbool

Whether to start with a fresh context (default: False)

capture_exceptionsbool

Whether to capture exceptions raised within the context (default: True)

Examples

Python
from posthog import new_context, tag, capture
with new_context():
tag("request_id", "123")
capture("event_name", properties={"property": "value"})

Returns

Type
None

scopedpublic

Decorator that creates a new context for the function.

Parameters

NameType
freshbool

Whether to start with a fresh context (default: False)

capture_exceptionsbool

Whether to capture and track exceptions with posthog error tracking (default: True)

Examples

Python
from posthog import scoped, tag, capture
@scoped()
def process_payment(payment_id):
tag("payment_id", payment_id)
capture("payment_started")

Returns

Type
None

set_context_sessionpublic

Set the session ID for the current context.

Parameters

NameType
session_id?str

The session ID to associate with the current context and its children

Examples

Python
from posthog import set_context_session
set_context_session("session_123")

Returns

Type
None

tagpublic

Add a tag to the current context.

Parameters

NameType
name?str

The tag key

value?typing.Any

The tag value

Examples

Python
from posthog import tag
tag("user_id", "123")

Returns

Type
None

Events methods

capturepublic

Capture anything a user does within your system.

Notes:

Capture allows you to capture anything a user does within your system, which you can later use in PostHog to find patterns in usage, work out which features to improve or where people are giving up. A capture call requires an event name to specify the event. We recommend using [verb] [noun], like movie played or movie updated to easily identify what your events mean later on. Capture takes a number of optional arguments, which are defined by the OptionalCaptureArgs type.

Parameters

NameType
event?str

The event name to specify the event **kwargs: Optional arguments including:

kwargs?typing_extensions.Unpack[OptionalCaptureArgs]

Parameter: kwargs

Examples

Python
# Context and capture usage
from posthog import new_context, identify_context, tag_context, capture
# Enter a new context (e.g. a request/response cycle, an instance of a background job, etc)
with new_context():
# Associate this context with some user, by distinct_id
identify_context('some user')
# Capture an event, associated with the context-level distinct ID ('some user')
capture('movie started')
# Capture an event associated with some other user (overriding the context-level distinct ID)
capture('movie joined', distinct_id='some-other-user')
# Capture an event with some properties
capture('movie played', properties={'movie_id': '123', 'category': 'romcom'})
# Capture an event with some properties
capture('purchase', properties={'product_id': '123', 'category': 'romcom'})
# Capture an event with some associated group
capture('purchase', groups={'company': 'id:5'})
# Adding a tag to the current context will cause it to appear on all subsequent events
tag_context('some-tag', 'some-value')
capture('another-event') # Will be captured with `'some-tag': 'some-value'` in the properties dict

Returns

Type
Optional[str]

capture_exceptionpublic

Capture exceptions that happen in your code.

Notes:

Capture exception is idempotent - if it is called twice with the same exception instance, only a occurrence will be tracked in posthog. This is because, generally, contexts will cause exceptions to be captured automatically. However, to ensure you track an exception, if you catch and do not re-raise it, capturing it manually is recommended, unless you are certain it will have crossed a context boundary (e.g. by existing a with posthog.new_context(): block already). If the passed exception was raised and caught, the captured stack trace will consist of every frame between where the exception was raised and the point at which it is captured (the "traceback"). If the passed exception was never raised, e.g. if you call posthog.capture_exception(ValueError("Some Error")), the stack trace captured will be the full stack trace at the moment the exception was captured. Note that heavy use of contexts will lead to truncated stack traces, as the exception will be captured by the context entered most recently, which may not be the point you catch the exception for the final time in your code. It's recommended to use contexts sparingly, for this reason. capture_exception takes the same set of optional arguments as capture.

Parameters

NameType
exceptionBaseException

The exception to capture. If not provided, the current exception is captured via sys.exc_info()

kwargs?typing_extensions.Unpack[OptionalCaptureArgs]

Parameter: kwargs

Examples

Python
# Capture exception
from posthog import capture_exception
try:
risky_operation()
except Exception as e:
capture_exception(e)

Returns

Type
None

Feature flags methods

feature_enabledpublic

Use feature flags to enable or disable features for users.

Notes:

You can call posthog.load_feature_flags() before to make sure you're not doing unexpected requests.

Parameters

NameType
key?any

The feature flag key

distinct_id?any

The user's distinct ID

groupsdict

Groups mapping

person_propertiesdict

Person properties

group_propertiesdict

Group properties

only_evaluate_locallybool

Whether to evaluate only locally

send_feature_flag_eventsbool

Whether to send feature flag events

disable_geoipany

Whether to disable GeoIP lookup

Examples

Python
# Boolean feature flag
from posthog import feature_enabled, get_feature_flag_payload
is_my_flag_enabled = feature_enabled('flag-key', 'distinct_id_of_your_user')
if is_my_flag_enabled:
matched_flag_payload = get_feature_flag_payload('flag-key', 'distinct_id_of_your_user')

Returns

Type
None

feature_flag_definitionspublic

Returns loaded feature flags.

Notes:

Returns loaded feature flags, if any. Helpful for debugging what flag information you have loaded.

Examples

Python
from posthog import feature_flag_definitions
definitions = feature_flag_definitions()

Returns

Type
None

get_all_flagspublic

Get all flags for a given user.

Notes:

Flags are key-value pairs where the key is the flag key and the value is the flag variant, or True, or False.

Parameters

NameType
distinct_id?any

The user's distinct ID

groupsdict

Groups mapping

person_propertiesdict

Person properties

group_propertiesdict

Group properties

only_evaluate_locallybool

Whether to evaluate only locally

disable_geoipany

Whether to disable GeoIP lookup

Examples

Python
# All flags for user
from posthog import get_all_flags
get_all_flags('distinct_id_of_your_user')

Returns

Type
Optional[dict[str, FeatureFlag]]

get_feature_flagpublic

Get feature flag variant for users. Used with experiments.

Notes:

groups are a mapping from group type to group key. So, if you have a group type of "organization" and a group key of "5", you would pass groups={"organization": "5"}. group_properties take the format: { group_type_name: { group_properties } }. So, for example, if you have the group type "organization" and the group key "5", with the properties name, and employee count, you'll send these as: group_properties={"organization": {"name": "PostHog", "employees": 11}}.

Parameters

NameType
key?any

The feature flag key

distinct_id?any

The user's distinct ID

groupsdict

Groups mapping from group type to group key

person_propertiesdict

Person properties

group_propertiesdict

Group properties in format { group_type_name: { group_properties } }

only_evaluate_locallybool

Whether to evaluate only locally

send_feature_flag_eventsbool

Whether to send feature flag events

disable_geoipany

Whether to disable GeoIP lookup

Examples

Python
# Multivariate feature flag
from posthog import get_feature_flag, get_feature_flag_payload
enabled_variant = get_feature_flag('flag-key', 'distinct_id_of_your_user')
if enabled_variant == 'variant-key':
matched_flag_payload = get_feature_flag_payload('flag-key', 'distinct_id_of_your_user')

Returns

Type
Optional[FeatureFlag]

load_feature_flagspublic

Load feature flag definitions from PostHog.

Examples

Python
from posthog import load_feature_flags
load_feature_flags()

Returns

Type
None

Identification methods

aliaspublic

Associate user behaviour before and after they e.g. register, login, or perform some other identifying action.

Notes:

To marry up whatever a user does before they sign up or log in with what they do after you need to make an alias call. This will allow you to answer questions like "Which marketing channels leads to users churning after a month?" or "What do users do on our website before signing up?". Particularly useful for associating user behaviour before and after they e.g. register, login, or perform some other identifying action.

Parameters

NameType
previous_id?any

The unique ID of the user before

distinct_id?any

The current unique id

timestampany

Optional timestamp for the event

uuidany

Optional UUID for the event

disable_geoipany

Whether to disable GeoIP lookup

Examples

Python
# Alias user
from posthog import alias
alias(previous_id='distinct_id', distinct_id='alias_id')

Returns

Type
None

group_identifypublic

Set properties on a group.

Parameters

NameType
group_type?any

Type of your group

group_key?any

Unique identifier of the group

propertiesany

Properties to set on the group

timestampany

Optional timestamp for the event

uuidany

Optional UUID for the event

disable_geoipany

Whether to disable GeoIP lookup

Examples

Python
# Group identify
from posthog import group_identify
group_identify('company', 'company_id_in_your_db', {
'name': 'Awesome Inc.',
'employees': 11
})

Returns

Type
None

identify_contextpublic

Identify the current context with a distinct ID.

Parameters

NameType
distinct_id?str

The distinct ID to associate with the current context and its children

Examples

Python
from posthog import identify_context
identify_context("user_123")

Returns

Type
None

setpublic

Set properties on a user record.

Notes:

This will overwrite previous people property values. Generally operates similar to capture, with distinct_id being an optional argument, defaulting to the current context's distinct ID. If there is no context-level distinct ID, and no override distinct_id is passed, this function will do nothing. Context tags are folded into $set properties, so tagging the current context and then calling set will cause those tags to be set on the user (unlike capture, which causes them to just be set on the event).

Parameters

NameType
kwargs?typing_extensions.Unpack[OptionalSetArgs]

Parameter: kwargs

Examples

Python
# Set person properties
from posthog import capture
capture(
'distinct_id',
event='event_name',
properties={
'$set': {'name': 'Max Hedgehog'},
'$set_once': {'initial_url': '/blog'}
}
)

Returns

Type
Optional[str]

set_oncepublic

Set properties on a user record, only if they do not yet exist.

Notes:

This will not overwrite previous people property values, unlike set. Otherwise, operates in an identical manner to set.

Parameters

NameType
kwargs?typing_extensions.Unpack[OptionalSetArgs]

Parameter: kwargs

Examples

Python
# Set property once
from posthog import capture
capture(
'distinct_id',
event='event_name',
properties={
'$set': {'name': 'Max Hedgehog'},
'$set_once': {'initial_url': '/blog'}
}
)

Returns

Type
Optional[str]

Other methods

get_remote_config_payloadpublic

Get the payload for a remote config feature flag.

Parameters

NameType
key?any

The key of the feature flag

Returns

Type
None

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