---
id: flipt-client
version: "1.4.3"
license: MIT
license_treatment: permissive
maintenance: active
---

# flipt-client — Flipt Client Evaluation SDK

License: permissive · Maintenance: active · Downloads: 157.6K/mo

## What it is and what it does

Flipt Client Python is a wrapper around the flipt-engine-ffi shared library that brings feature flag evaluation into your Python application. It fetches flag definitions from a Flipt server once at startup, then performs all subsequent flag evaluations locally within the SDK—meaning your application can evaluate flags even if the Flipt server becomes temporarily unreachable. The client supports two data-fetch modes: polling (checking for updates at a configurable interval, defaulting to 120 seconds) and streaming (for Flipt Cloud and Flipt v2, receiving real-time flag changes over a persistent connection). It handles transient network failures automatically with exponential backoff retries.

The package depends on pydantic for response models and packaging for version handling. It supports Linux, macOS, and Windows across x86_64 and arm64 architectures. The client requires Python 3.11 or later and offers flexible authentication (none, client token, or JWT), TLS configuration for custom certificates and mutual TLS, and an error strategy choice between failing fast or falling back to a snapshot. All responses are strongly typed Pydantic models, and errors inherit from a common FliptError base class.

Use it for:

- Evaluate feature flags in production without adding a network round-trip on every flag check, using locally cached flag state.
- Build resilient applications that can continue evaluating flags during temporary Flipt server outages or network degradation.
- Stream real-time flag changes to your application using Flipt Cloud or Flipt v2, keeping flag state synchronized without polling overhead.
- Authenticate to Flipt using client tokens or JWTs, with optional mutual TLS for secure server communication.
- Test feature flag logic in CI/CD pipelines using a snapshot of engine state without requiring a live Flipt server.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

A Python client for Flipt feature flag evaluation that performs flag decisions locally within the SDK after fetching flag state from a Flipt server.

Yes. The package is actively maintained, has no known vulnerabilities, and offers low install friction with only two lightweight dependencies. It solves a real problem—local flag evaluation with fallback resilience—and is well-suited for production use if you are already running Flipt. Install it if your application needs feature flags with offline evaluation capability or reduced latency per flag check.

## Install

pip install flipt-client
uv add flipt-client
poetry add flipt-client

## Installing flipt-client

Before you install: Low install friction with only two runtime dependencies (pydantic and packaging). The package is actively maintained with a recent release and no known vulnerabilities.

License in practice: MIT license permits commercial and private use with minimal restrictions; you may use, modify, and distribute the package freely provided you include the license notice.

Quickstart:

pip install flipt-client

from flipt_client import FliptClient
from flipt_client.models import ClientOptions

client = FliptClient(opts=ClientOptions(url="http://localhost:8080"))
result = client.evaluate_variant(flag_key="flag1", entity_id="entity", context={})
client.close()

Requires Python 3.11 or later; requires a running Flipt server instance to fetch initial flag state.

Verify before relying:

- Whether the embedded flipt-engine-ffi shared library is automatically downloaded and installed, or if manual setup is required.
- Performance characteristics and memory footprint when evaluating large numbers of flags or contexts.
- Compatibility with non-standard or air-gapped network environments beyond what TLS configuration covers.

## Package facts

- License: MIT (permissive)
- Python support: supports_current
- Install friction: low
- Maintenance: active
- Downloads: 157.6K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

feature flag evaluation client, flipt sdk python, client-side feature flags, local flag evaluation, feature flag polling streaming, feature-flags, client-sdk

[View on SkillFed](https://skillfed.io/packages/flipt-client) · [View on PyPI](https://pypi.org/project/flipt-client/)