/onboardingv2

Python (Server) — SDK detail

• Official docs: Python SDK reference
• API reference: launchdarkly-server-sdk (Read the Docs)
• Published package: launchdarkly-server-sdk (PyPI)
• Recipe (detect / install): SDK Recipes (Python Server)

Use a current launchdarkly-server-sdk release; see the SDK releases page and version compatibility (Python 3.9+ from SDK 9.12+).

Install (Install the SDK):

pip install launchdarkly-server-sdk

Optional observability (Python observability) — requires Python SDK 9.12+:

pip install launchdarkly-observability

Import (same topic):

import ldclient
from ldclient.config import Config

# Optional — launchdarkly-observability package; requires Python SDK v9.12+
# from ldobserve import ObservabilityPlugin

Initialize: Call ldclient.set_config(Config(...)) once, then ldclient.get() for the singleton client (Initialize the client). With observability: Config(sdk_key, plugins=[ObservabilityPlugin()]). Worker processes that fork may need postfork() (Considerations with worker-based servers).

Includes: Minimal onboarding script. SDK key: LAUNCHDARKLY_SDK_KEY (Apply: environment configuration).

import os
import sys

import ldclient
from ldclient.config import Config

if __name__ == "__main__":
    sdk_key = os.environ.get("LAUNCHDARKLY_SDK_KEY")
    if not sdk_key or not sdk_key.strip():
        print(
            "LAUNCHDARKLY_SDK_KEY is not set. Use Project settings > Environments > SDK key.",
            file=sys.stderr,
        )
        raise SystemExit(1)

    ldclient.set_config(Config(sdk_key))
    client = ldclient.get()

    if not client.is_initialized():
        print("LaunchDarkly client failed to initialize", file=sys.stderr)
        raise SystemExit(1)

    # For onboarding only — events are normally flushed in the background.
    client.flush()
    print("LaunchDarkly client ready.")