fireweave (Python SDK)

Fireweave polyglot SDK for Python — OpenFeature-compatible, server-first flag evaluation with release-safety extensions (spec v0.1.0).

• Core: zero runtime dependencies (fireweave + InMemoryAdapter).
• Extras: fireweave[posthog] (PostHog backend, posthog==7.31.0), fireweave[openfeature] (OpenFeature provider, openfeature-sdk>=0.10,<0.11).

Quick start (offline, in-memory)

from fireweave import FireweaveClient, FireweaveRuntime, InMemoryAdapter

adapter = InMemoryAdapter({
    "new-checkout": {"type": "boolean", "enabled": True, "variant": "on", "value": True},
})
runtime = FireweaveRuntime(adapter)
runtime.initialize()
client = FireweaveClient(runtime)

assert client.flags.get_boolean_value("new-checkout", False) is True
client.shutdown()

OpenFeature

from openfeature import api
from fireweave import FireweaveRuntime, InMemoryAdapter
from fireweave.openfeature import FireweaveProvider

api.set_provider(FireweaveProvider(FireweaveRuntime(InMemoryAdapter({...}))))
client = api.get_client()
client.get_boolean_value("new-checkout", False)

PostHog backend

from fireweave import FireweaveConfig, FireweaveRuntime, FireweaveClient
from fireweave.adapters.posthog import PostHogAdapter

config = FireweaveConfig(project_api_key="phc_...", host="https://us.i.posthog.com")
runtime = FireweaveRuntime(PostHogAdapter(config=config), config)
runtime.initialize(backend_required=True)
client = FireweaveClient(runtime)

Sync / async

The core is a thread-safe sync runtime; asyncio servers use fireweave.aio.AsyncFireweaveClient, which offloads calls via asyncio.to_thread. See docs/adr/0004 and the module docstring.

Development

python -m venv .venv && .venv/bin/pip install -e '.[dev]'
.venv/bin/pytest                                   # unit + conformance tests
.venv/bin/python conformance/run_conformance.py    # normalized results JSON