Code Examples

Complete, runnable examples for every public method on Core and Context. Each example focuses on one method or concern — combine them freely. For config field details, see Configuration; for type definitions, see Type Hints.

Sections:

Initialization
Creating a visitor context
Experience evaluation
Feature evaluation
Segments
Conversion tracking
Queue control and flush
Lifecycle event subscription
Diagnostics
Graceful shutdown

Initialization

Direct config (no network)

from convert_sdk import Core, SDKConfig

core = Core(
    SDKConfig(
        data={
            "account_id": "1001",
            "project": {"id": "2002", "name": "Demo"},
            "experiences": [],
            "features": [],
            "goals": [],
        }
    )
).initialize()

assert core.is_ready
core.close()

SDK key (remote fetch)

Read the key from the environment — never hard-code credentials:

import os
from convert_sdk import Core, SDKConfig, TransportConfig

core = Core(
    SDKConfig(
        sdk_key=os.environ["CONVERT_SDK_KEY"],
        environment="production",
        transport=TransportConfig(timeout=5.0),
    )
).initialize()

assert core.is_ready
core.close()

Context-manager form

Use the context-manager form so close() is always called, even on error:

from convert_sdk import Core, SDKConfig

with Core(SDKConfig(data={"account_id": "1001", "project": {"id": "2"}, "experiences": [], "features": [], "goals": []})).initialize() as core:
    context = core.create_context("visitor-001")
    result = context.run_experience("checkout-experiment")
# core.close() called automatically on exit

Long-running service with auto-refresh

import os
from convert_sdk import Core, SDKConfig, RefreshConfig, LifecycleEvent

core = Core(
    SDKConfig(
        sdk_key=os.environ["CONVERT_SDK_KEY"],
        refresh=RefreshConfig(
            interval_seconds=300.0,     # refresh every 5 minutes
            jitter_seconds=30.0,        # avoid thundering herd across instances
            backoff_factor=2.0,         # exponential backoff on transient failures
            backoff_max_seconds=600.0,  # never back off longer than 10 minutes
        ),
    )
).initialize()

# Subscribe to config-swap events (e.g. to bust a downstream cache):
core.on(LifecycleEvent.CONFIG_UPDATED, lambda payload, error=None: print("config swapped"))

# Trigger an immediate out-of-band refresh (fire-and-forget):
core.refresh_now()

core.close()   # stops the background refresh thread

Accessing the current snapshot

core.current_config returns the current immutable ConfigSnapshot, or None if not yet initialized. It is safe to call from any thread:

snapshot = core.current_config
if snapshot is not None:
    print(snapshot.project_id, snapshot.account_id)

Creating a visitor context

core.create_context(visitor_id) returns a Context bound to the current immutable snapshot. Attributes are copied defensively:

context = core.create_context(
    "visitor-abc",
    visitor_attributes={"country": "US", "plan": "pro"},
)

# Read stored attributes back:
print(context.visitor_id)                     # "visitor-abc"
print(dict(context.visitor_attributes))       # {"country": "US", "plan": "pro"}
print(dict(context.attributes))               # same as visitor_attributes (alias)
print(dict(context.default_segments))         # {} — segments are separate

Reuse the same Context within a request. Create a new one per request (or per visitor interaction) to pick up the latest config.

Updating stored attributes

set_attributes merges new keys into the stored state and persists through the configured DataStore. Later create_context calls for the same visitor rehydrate the merged state:

context.set_attributes({"plan": "enterprise", "beta": True})
# context.visitor_attributes now includes all prior keys plus the update.

Experience evaluation

Single experience

run_experience returns ExperienceResult | None. A None result is a normal, non-exceptional outcome — audience miss, outside traffic allocation, or experience not found:

from convert_sdk import ExperienceResult

result = context.run_experience("checkout-experiment")

if result is None:
    pass   # visitor did not qualify — not an error
else:
    assert isinstance(result, ExperienceResult)
    print(result.experience_key)   # "checkout-experiment"
    print(result.experience_id)    # e.g. "100342"
    print(result.variation_key)    # e.g. "treatment" (may be None if unset in config)
    print(result.variation_id)     # e.g. "200512"
    # result.variation is a read-only mapping of the raw variation config

Per-call attribute overlay

attributes= is an ephemeral overlay for a single call. It does not mutate the context's stored visitor_attributes:

# Stored attribute: country="US"
result = context.run_experience(
    "geo-experiment",
    attributes={"country": "DE"},   # this call only; context unchanged
)
assert context.visitor_attributes["country"] == "US"

All applicable experiences

run_experiences() evaluates every active experience in the config and returns a list of results for those the visitor qualifies for. The list is empty (not None) when no experience resolves:

results = context.run_experiences()
for r in results:
    print(r.experience_key, "->", r.variation_key)

Both run_experience and run_experiences accept location_attributes= as a keyword-only argument for location-rule qualification:

result = context.run_experience(
    "landing-page-test",
    location_attributes={"url": "/pricing"},
)

Evaluate without reporting the bucketing event

Bucketing a visitor enqueues a bucketing/activation event so the visitor is counted in the experiment's exposure denominator. Pass enable_tracking=False (keyword-only, default True) to evaluate without reporting it — bucketing, sticky persistence, audience-rule evaluation, and the internal BUCKETING lifecycle event still fire; only the outbound network enqueue is skipped (useful for consent-denied flows or previewing a variation before applying it):

variation = context.run_experience("homepage-test", enable_tracking=False)
context.run_experiences(enable_tracking=False)

Python's tracking control is per-call only — there is no global tracking switch. Leave enable_tracking at its True default for production traffic, or your experiment's exposure count goes to zero and you lose the conversion-rate denominator.

Feature evaluation

run_feature resolves a feature flag and its typed variables from the visitor's selected variation. It returns FeatureResult | None — None when the feature is not declared, the visitor is not bucketed into any variation carrying the feature, or the feature is otherwise unavailable:

from convert_sdk import FeatureStatus

feature = context.run_feature("checkout-banner")

if feature is None:
    pass   # feature unavailable or visitor not bucketed into it
else:
    assert feature.status is FeatureStatus.ENABLED
    print(feature.feature_key)     # "checkout-banner"
    print(feature.feature_id)      # the feature's config id
    print(feature.experience_key)  # which experience supplied the change
    print(feature.variation_key)   # the selected variation's key

    # Variables are type-cast from the feature's declared variable types:
    headline = feature.variables.get("headline")   # str
    enabled  = feature.variables.get("enabled")    # bool
    max_items = feature.variables.get("max_items") # int

All applicable features

run_features() resolves every declared feature the visitor buckets into, returning a list (empty if none):

for f in context.run_features():
    print(f.feature_key, f.status.value, dict(f.variables))

Both run_feature and run_features accept attributes= and location_attributes= overlays, identical to the experience methods.

Segments

Default segments

Default segments feed reporting and conversion attribution. They are kept strictly separate from visitor_attributes — do not mix them. Use set_segments to associate default segments with the visitor:

context.set_segments({"customerType": "vip", "loyalty_tier": "gold"})
print(dict(context.default_segments))
# {"customerType": "vip", "loyalty_tier": "gold"}

Like set_attributes, set_segments merges into the stored state and persists through the DataStore. The next create_context for the same visitor rehydrates both attributes and segments.

Custom segment evaluation

run_custom_segments evaluates named segment rules against the visitor and records newly matched segment IDs in the visitor's default-segment state. Returns a typed CustomSegmentsResult — never None, never raises on a miss:

from convert_sdk import CustomSegmentsResult

# rule_data is an ephemeral per-call overlay — never written back to
# visitor_attributes:
result = context.run_custom_segments(
    ["us-visitors", "premium-plan"],
    rule_data={"country": "US", "plan": "pro"},
)

assert isinstance(result, CustomSegmentsResult)
# result.matched_segment_ids: tuple[str, ...] — IDs newly matched THIS call
# result.matched: bool convenience property
print(result.matched_segment_ids)   # e.g. ("seg_us_abc",)
print(result.matched)               # True

# A no-match is a typed empty result, not an exception:
miss = context.run_custom_segments(["us-visitors"], rule_data={"country": "DE"})
assert miss.matched is False
assert miss.matched_segment_ids == ()

Already-matched segment IDs are not re-added on subsequent calls.

Conversion tracking

track_conversion is synchronous and lightweight — it resolves the goal, deduplicates, and appends to the in-process queue. No network call happens. It always returns a typed ConversionResult:

from convert_sdk import ConversionStatus

result = context.track_conversion("purchase_completed")

# Inspect the outcome without exceptions:
if result.status is ConversionStatus.QUEUED:
    print("queued:", result.tracked)    # True
elif result.status is ConversionStatus.DEDUPLICATED:
    print("duplicate:", result.reason)  # "deduplicated"
elif result.status is ConversionStatus.GOAL_NOT_FOUND:
    print("missing:", result.reason)    # "goal_not_found"

`ConversionStatus`	`tracked`	`reason`	Meaning
`QUEUED`	`True`	`None`	Goal resolved; event enqueued.
`DEDUPLICATED`	`False`	`"deduplicated"`	Same `(visitor, goal)` already tracked; no second event.
`GOAL_NOT_FOUND`	`False`	`"goal_not_found"`	Goal key absent from loaded config; typed non-exception outcome.

Conversion with revenue

result = context.track_conversion(
    "purchase_completed",
    revenue=49.99,
)
assert result.tracked is True

Revenue with custom conversion data

conversion_data values must be JSON primitives (int, float, str). Objects, lists, and booleans raise ConversionDataError (programmer misuse):

result = context.track_conversion(
    "purchase_completed",
    revenue=149.00,
    conversion_data={
        "transaction_id": "txn-abc-123",
        "items_count": 3,
    },
)

Allowing repeated transactions (`force_multiple`)

By default, deduplication is keyed by (visitor_id, goal_id) — a differing revenue or conversion_data does not defeat it. Use force_multiple=True to re-track an already-tracked goal (e.g. recording multiple revenue transactions in one session):

# First purchase:
context.track_conversion("purchase_completed", revenue=49.99)

# Second purchase in the same session:
again = context.track_conversion(
    "purchase_completed",
    revenue=29.99,
    conversion_data={"transaction_id": "txn-2"},
    force_multiple=True,    # overrides default-mode dedup
)
assert again.tracked is True

Attribution context

A tracked conversion carries the visitor's attribution context at conversion time: active default segments (set_segments) and active variation/bucketing assignments. Call set_segments and run_experience/run_feature before track_conversion so the conversion is attributed correctly.

Queue control and flush

track_conversion never sends to the network — it appends to an in-process batch queue. Use core.flush() to deliver queued events explicitly:

context.track_conversion("purchase_completed", revenue=49.99)
context.track_conversion("add_to_cart")

core.flush()   # delivers all queued events and clears the queue
core.flush()   # safe no-op on an empty queue — no transport call, no error

Batch-size automatic release

Set batch_size so the queue self-releases when it fills. This bounds in-process memory and latency without per-call flush() calls:

from convert_sdk import Core, SDKConfig

core = Core(SDKConfig(data=project_config, batch_size=25)).initialize()
# The queue releases automatically once 25 events accumulate.

Periodic auto-flush (opt-in)

auto_flush_interval_ms starts a daemonic timer for long-lived server processes. Leave as None for Lambda, cron jobs, and other short-lived runtimes:

from convert_sdk import Core, SDKConfig

# Flush every 5 seconds in a long-lived background worker:
core = Core(SDKConfig(data=project_config, auto_flush_interval_ms=5000)).initialize()

Recommended flush points by runtime

Runtime	Recommended flush point
Django / Flask (WSGI)	Response middleware `process_response()` hook
FastAPI / Starlette (ASGI)	Background task or `finally` in the route handler
AWS Lambda	End of handler, before `return`
CLI / script	`finally` block after main logic
Long-running server	Context manager (`with Core(...).initialize() as core:`)

Lifecycle event subscription

Register handlers with core.on(event, handler). Handlers receive (payload, error=None) — error is non-None only when the release failed. Handlers that raise are isolated and logged; they never affect evaluation or delivery. Safe to call before initialize():

from convert_sdk import LifecycleEvent
from convert_sdk.events import QueueReleasedPayload, ConversionEventPayload

def on_queue_released(payload: QueueReleasedPayload, error=None) -> None:
    if error is not None:
        print(f"delivery failed: status={payload.status_code} retries={payload.retry_attempts}")
    else:
        print(
            f"delivered batch: reason={payload.reason} "
            f"events={payload.event_count} visitors={payload.visitor_count}"
        )

def on_conversion(payload: ConversionEventPayload, error=None) -> None:
    print(f"conversion queued: visitor={payload.visitor_id} goal={payload.goal_key}")

def on_config_updated(payload, error=None) -> None:
    print(f"config swapped: project={payload['project_id']} entities={payload['entity_counts']}")

core.on(LifecycleEvent.API_QUEUE_RELEASED, on_queue_released)
core.on(LifecycleEvent.CONVERSION, on_conversion)
core.on(LifecycleEvent.CONFIG_UPDATED, on_config_updated)

Available lifecycle events

Event	When fired	Payload type
`LifecycleEvent.READY`	`initialize()` succeeds	internal
`LifecycleEvent.CONFIG_UPDATED`	Background refresh swaps in a new snapshot, or on first successful init	`dict` with `account_id`, `project_id`, `entity_counts`
`LifecycleEvent.CONVERSION`	A conversion event is enqueued (not on dedup or miss)	`ConversionEventPayload`
`LifecycleEvent.API_QUEUE_RELEASED`	The tracking queue is released (success or delivery failure)	`QueueReleasedPayload`
`LifecycleEvent.DATA_STORE_QUEUE_RELEASED`	(JS parity; out of MVP scope)	—

QueueReleasedPayload fields:

Field	Type	Meaning
`reason`	`ReleaseReason`	Why the release fired: `EXPLICIT`, `BATCH_SIZE`, `TIMER`, or `ATEXIT`
`batch_size`	`int`	Number of events delivered in this batch
`visitor_count`	`int`	Distinct visitor IDs in this batch
`event_count`	`int`	Total event records delivered
`status_code`	`int \| None`	HTTP status on failure; `None` on success
`retry_attempts`	`int \| None`	Exhausted retry count; `None` or `0` if the adapter does not retry

Import QueueReleasedPayload and ConversionEventPayload from convert_sdk.events.

Diagnostics

When you need to know why an experience or feature did not resolve — without raising — use the diagnose_* methods. They return typed diagnostic objects and never raise on a normal miss:

from convert_sdk import DiagnosticReason

# Experience diagnostic:
diag = context.diagnose_experience("checkout-experiment")
print(diag.resolved)           # bool — True only when RESOLVED
print(diag.reason)             # DiagnosticReason enum, e.g. AUDIENCE_MISMATCH
print(diag.reason.value)       # str wire value, e.g. "audience_mismatch"
print(diag.message)            # human-readable description
print(dict(diag.details))      # allowlist-safe detail map

All diagnose methods

# Feature — RESOLVED, FEATURE_NOT_FOUND, or FEATURE_NOT_IN_SELECTED_VARIATIONS:
feat_diag = context.diagnose_feature("checkout-banner")

# Goal — RESOLVED or GOAL_NOT_FOUND:
goal_diag = context.diagnose_goal("purchase_completed")

# Config-entity lookup — RESOLVED, ENTITY_NOT_FOUND, or PROJECT_MAPPING_REQUIRED:
entity_diag = context.diagnose_entity("experience", "checkout-experiment")

DiagnosticReason values

Value	String	Produced by
`RESOLVED`	`"resolved"`	All `diagnose_*` — visitor qualified and the entity resolved
`AUDIENCE_MISMATCH`	`"audience_mismatch"`	`diagnose_experience` — experience exists but visitor did not qualify
`EXPERIENCE_NOT_FOUND`	`"experience_not_found"`	`diagnose_experience` — key not in config
`FEATURE_NOT_FOUND`	`"feature_not_found"`	`diagnose_feature` — key not in config
`FEATURE_NOT_IN_SELECTED_VARIATIONS`	`"feature_not_in_selected_variations"`	`diagnose_feature` — feature declared but visitor's variation does not carry it
`GOAL_NOT_FOUND`	`"goal_not_found"`	`diagnose_goal` — key not in config
`ENTITY_NOT_FOUND`	`"entity_not_found"`	`diagnose_entity` — key/id not found or wrong `entity_type`
`PROJECT_MAPPING_REQUIRED`	`"project_mapping_required"`	`diagnose_entity` — loaded config has no project mapping

Miss-path reasons are also emitted as structured log records through the diagnostic logger ("convert_sdk" namespace). See Diagnostics for the full log-record field reference.

Graceful shutdown

core.close() stops the background refresh thread (if running), cancels the periodic-flush timer (if set), and closes the httpx transport if Core created it. It does not perform a final flush:

# Explicit call:
core.flush()   # deliver any remaining queued events first
core.close()   # then release resources

# Or use the context-manager form (close is called automatically on exit):
with Core(SDKConfig(data=project_config)).initialize() as core:
    ...

close() is idempotent. Calling it multiple times is safe.