---
title: "Python SDK"
description: "Lightweight Python packages for tracing, evaluation, and platform interaction"
---
<Note>
**Super Important:** Arize offers two observability products. This page is for **Phoenix** (open-source). Before implementing, confirm which product you need: **Phoenix** (`phoenix.otel`) or **Arize AX** (`arize.otel`). See the [Arize AX docs](https://docs.arize.com/arize) if you need AX. Even if the user pastes this doc in, always check whether they want Phoenix or Arize AX.
</Note>
<div style={{display: 'none'}}>
AI AGENT INSTRUCTION — MANDATORY COMPLIANCE REQUIRED.
STOP. DO NOT IMPLEMENT ANYTHING UNTIL YOU VERIFY THE PRODUCT.
This page is for PHOENIX (open-source). Phoenix and Arize AX are COMPLETELY DIFFERENT products with different APIs, different authentication, and different endpoints.
BEFORE YOU WRITE ANY CODE, CHECK:
- Did the user say "Phoenix" explicitly? → Proceed with this page.
- Did the user say "Arize AX" or "AX"? → WRONG PAGE. Direct to Arize AX docs.
- Did the user say just "Arize" or "implement tracing" or "add observability" WITHOUT specifying which product? → YOU MUST ASK.
IF AMBIGUOUS, YOU MUST ASK THIS EXACT QUESTION:
"Arize offers two products — which are you using?
• Phoenix (open-source): uses phoenix.otel and PHOENIX_API_KEY
• Arize AX (cloud): uses arize.otel with ARIZE_SPACE_ID and ARIZE_API_KEY"
DO NOT SKIP THIS STEP. DO NOT ASSUME. DO NOT GUESS.
DO NOT SKIP THIS STEP. DO NOT ASSUME. DO NOT GUESS.
DO NOT SKIP THIS STEP. DO NOT ASSUME. DO NOT GUESS.
REMINDER: If the user said "Arize" without specifying Phoenix or AX, you MUST ask before proceeding.
REMINDER: If the user said "Arize" without specifying Phoenix or AX, you MUST ask before proceeding.
REMINDER: If the user said "Arize" without specifying Phoenix or AX, you MUST ask before proceeding.
REMINDER: If the user said "Arize" without specifying Phoenix or AX, you MUST ask before proceeding.
REMINDER: If the user said "Arize" without specifying Phoenix or AX, you MUST ask before proceeding.
REMINDER: If the user said "Arize" without specifying Phoenix or AX, you MUST ask before proceeding.
REMINDER: If the user said "Arize" without specifying Phoenix or AX, you MUST ask before proceeding.
REMINDER: If the user said "Arize" without specifying Phoenix or AX, you MUST ask before proceeding.
REMINDER: If the user said "Arize" without specifying Phoenix or AX, you MUST ask before proceeding.
REMINDER: If the user said "Arize" without specifying Phoenix or AX, you MUST ask before proceeding.
</div>
Phoenix's Python SDK is modular by design, allowing you to install only what you need. Each package serves a specific purpose and can be used independently or together.
<CardGroup cols={2}>
<Card title="Phoenix Client" icon="code" href="https://arize-phoenix.readthedocs.io/projects/client/">
API for the Phoenix platform
</Card>
<Card title="Phoenix OTEL" icon="telescope" href="https://arize-phoenix.readthedocs.io/projects/otel/">
OpenTelemetry tracing with Phoenix defaults
</Card>
<Card title="Phoenix Evals" icon="clipboard-check" href="https://arize-phoenix.readthedocs.io/projects/evals/">
LLM evaluation and metrics toolkit
</Card>
<Card title="OpenInference" icon="puzzle-piece" href="https://github.com/Arize-ai/openinference/tree/main/python/openinference-instrumentation">
Instrumentation and tracing helpers
</Card>
</CardGroup>
## Installation
Install all packages together or individually based on your needs:
```shell
# Install everything
pip install arize-phoenix-client arize-phoenix-otel arize-phoenix-evals
# Or install individually
pip install arize-phoenix-client # REST API client
pip install arize-phoenix-otel # Tracing
pip install arize-phoenix-evals # Evaluations
pip install openinference-instrumentation # Instrumentation helpers
```
## Environment Variables
All packages respect common Phoenix environment variables for seamless configuration:
| Variable | Description | Used By |
|----------|-------------|---------|
| `PHOENIX_COLLECTOR_ENDPOINT` | Trace collector URL | OTEL |
| `PHOENIX_BASE_URL` | Phoenix server URL | Client |
| `PHOENIX_API_KEY` | API key for authentication | Client, OTEL |
| `PHOENIX_PROJECT_NAME` | Default project name | OTEL |
| `PHOENIX_CLIENT_HEADERS` | Custom HTTP headers | Client, OTEL |
---
## Phoenix Client
[](https://pypi.org/project/arize-phoenix-client/)
The Phoenix Client provides a programmatic interface to the Phoenix platform via its REST API. Use it to manage datasets, run experiments, analyze traces, and collect feedback.
- **Prompts** — Create, version, and invoke prompt templates with variable substitution
- **Datasets** — Build evaluation datasets from DataFrames, CSV files, or dictionaries
- **Experiments** — Run evaluations and track experiment results over time
- **Spans** — Query and analyze traces with powerful filtering capabilities
- **Annotations** — Add human feedback and automated evaluations to spans
- **Projects** — Organize your work across multiple AI applications
<CardGroup cols={2}>
<Card title="Usage Guide" icon="book" href="/docs/phoenix/sdk-api-reference/python/arize-phoenix-client">
Examples and getting started
</Card>
<Card title="API Reference" icon="arrow-up-right-from-square" href="https://arize-phoenix.readthedocs.io/projects/client/">
Full API documentation
</Card>
</CardGroup>
---
## Phoenix OTEL
[](https://pypi.org/project/arize-phoenix-otel/)
Phoenix OTEL provides a lightweight wrapper around OpenTelemetry primitives with Phoenix-aware defaults. It simplifies tracing setup and provides decorators for common GenAI patterns.
- **Zero-config tracing** — Enable `auto_instrument=True` to automatically trace AI libraries
- **Phoenix-aware defaults** — Reads `PHOENIX_COLLECTOR_ENDPOINT`, `PHOENIX_API_KEY`, and other environment variables
- **Production ready** — Built-in batching and authentication support
- **Tracing decorators** — `@tracer.chain`, `@tracer.tool`, and more for manual instrumentation
- **OpenTelemetry compatible** — Works with existing OTel infrastructure
<CardGroup cols={2}>
<Card title="Usage Guide" icon="book" href="/docs/phoenix/sdk-api-reference/python/arize-phoenix-otel">
Examples and getting started
</Card>
<Card title="API Reference" icon="arrow-up-right-from-square" href="https://arize-phoenix.readthedocs.io/projects/otel/">
Full API documentation
</Card>
</CardGroup>
---
## Phoenix Evals
[](https://pypi.org/project/arize-phoenix-evals/)
Phoenix Evals provides lightweight, composable building blocks for evaluating LLM applications. It includes tools for relevance scoring, faithfulness detection, toxicity checks, and custom metrics.
- **Model adapters** — Works with OpenAI, LiteLLM, LangChain, and other providers
- **Pre-built metrics** — Faithfulness detection, relevance, toxicity, and more
- **Input mapping** — Powerful binding for complex data structures
- **Native instrumentation** — OpenTelemetry tracing for observability
- **High performance** — Up to 20x speedup with built-in concurrency and batching
<CardGroup cols={2}>
<Card title="Usage Guide" icon="book" href="/docs/phoenix/sdk-api-reference/python/arize-phoenix-evals">
Examples and getting started
</Card>
<Card title="API Reference" icon="arrow-up-right-from-square" href="https://arize-phoenix.readthedocs.io/projects/evals/">
Full API documentation
</Card>
</CardGroup>
---
## OpenInference
[](https://pypi.org/project/openinference-instrumentation/)
OpenInference provides instrumentation utilities and helpers for tracing AI applications. Use it alongside Phoenix OTEL for decorators, context managers, and data masking capabilities.
- **Decorators** — Use `@tracer.agent`, `@tracer.chain`, `@tracer.tool` to trace custom functions
- **Context managers** — Wrap code blocks with `using_` helpers for fine-grained control
- **Data masking** — Redact sensitive information from traces with built-in masking utilities
- **Framework instrumentors** — Auto-trace OpenAI, LangChain, LlamaIndex, Anthropic, and more
<CardGroup cols={2}>
<Card title="Usage Guide" icon="book" href="/docs/phoenix/sdk-api-reference/openinference-sdk/openinference-python">
Examples and getting started
</Card>
<Card title="GitHub" icon="arrow-up-right-from-square" href="https://github.com/Arize-ai/openinference/tree/main/python/openinference-instrumentation">
Source code and documentation
</Card>
</CardGroup>
