Get Started: Tracing

Now that you have Phoenix up and running, the next step is to start sending traces from your Python application. Traces let you see what’s happening inside your system, including function calls, LLM requests, tool calls, and other operations.

Launch Phoenix

Before sending traces, make sure Phoenix is running. For more step by step instructions, check out this Get Started guide.

In your code, set your environment variables.

import os
os.environ["PHOENIX_API_KEY"] = "ADD YOUR PHOENIX API KEY"
os.environ["PHOENIX_COLLECTOR_ENDPOINT"] = "ADD YOUR PHOENIX Collector endpoint"

You can find your collector endpoint here:

After launching your space, go to settings.

Your Collector Endpoint is: https://app.phoenix.arize.com/s/ + your space name.

Install the Phoenix OTEL Package

To collect traces from your application, you must configure an OpenTelemetry TracerProvider to send traces to Phoenix.

pip install arize-phoenix-otel

Set-Up Tracing

There are two ways to trace your application: manually, or automatically with an auto-instrumentor. OpenInference provides the auto-instrumenter option through ready-to-use integrations with popular frameworks, so you can capture traces without adding manual logging code.

Phoenix can capture all calls made to supported libraries automatically. Just install the associated library.

pip install openinference-instrumentation-openai

Phoenix can capture all calls made to supported libraries automatically. Just install the associated library.

# npm, pnpm, yarn, etc
npm install openai @arizeai/openinference-instrumentation-openai

Update your instrumentation.tsfile, registering the instrumentation. Steps will vary depending on if your project is configured for CommonJS or ESM style module resolution.

// instrumentation.ts

// ... rest of imports
import OpenAI from "openai"
import { registerInstrumentations } from "@arizeai/phoenix-otel";
import { OpenAIInstrumentation } from "@arizeai/openinference-instrumentation-openai";

// ... previous code

const instrumentation = new OpenAIInstrumentation();
instrumentation.manuallyInstrument(OpenAI);

registerInstrumentations({
  instrumentations: [instrumentation],
});

// instrumentation.ts

// ... rest of imports
import { registerInstrumentations } from "@arizeai/phoenix-otel";
import { OpenAIInstrumentation } from "@arizeai/openinference-instrumentation-openai";

// ... previous code

registerInstrumentations({
  instrumentations: [new OpenAIInstrumentation()],
});

Your project can be configured for CommonJS or ESM via many methods. It can depend on your installed runtime (Node, Deno, etc), as well as configuration within your `package.json`. Consult your runtime documentation for more details.

Trace your own functions using OpenInference/OpenTelemetry.

Functions can be traced using decorators:

@tracer.chain
def my_func(input: str) -> str:
    return "output"

Input and output attributes are set automatically based on my_func's parameters and return.

For Manually tracing your whole application, check out our guide on manual tracing using OpenInference/OpenTelemetry.

Register a Tracer

In your Python code, register Phoenix as the trace provider. This connects your application to Phoenix, making a project in the UI after you send a trace, and optionally enables auto-instrumentation (automatic tracing for supported libraries like OpenAI).

from phoenix.otel import register

tracer_provider = register(
    project_name="my-llm-app",
    auto_instrument=True,
)

tracer = tracer_provider.get_tracer(__name__)

In a new file called instrumentation.ts (or .js if applicable)

// instrumentation.ts
import { register } from "@arizeai/phoenix-otel";

const provider = register({
  projectName: "my-llm-app", // Sets the project name in Phoenix UI
});

The register function automatically:

Reads PHOENIX_COLLECTOR_ENDPOINT and PHOENIX_API_KEY from environment variables
Configures the collector endpoint (defaults to http://localhost:6006)
Sets up batch span processing for production use
Registers the provider globally

Environment Variables:

PHOENIX_COLLECTOR_ENDPOINT - The URL to your Phoenix instance (e.g., https://app.phoenix.arize.com)
PHOENIX_API_KEY - Your Phoenix API key for authentication

Now, import this file at the top of your main program entrypoint, or invoke it with the node cli's --require flag:

Import Method:
- In main.ts or similar: import "./instrumentation.ts"
- In your CLI, script, Dockerfile, etc: node main.ts
--require Method:
- In your CLI, script, Dockerfile, etc: node --require ./instrumentation.ts main.ts

Start Your Application

Now that you have set up tracing & your project in Phoenix, it's time to actually invoke your llm, agent, or application.

First add your OpenAI API Key & then invoke the model.

import os
from getpass import getpass

if not (openai_api_key := os.getenv("OPENAI_API_KEY")):
    openai_api_key = getpass("🔑 Enter your OpenAI API key: ")

os.environ["OPENAI_API_KEY"] = openai_api_key

# Add OpenAI API Key
import openai

client = openai.OpenAI()
response = client.chat.completions.create(
    model="gpt-4o",
    messages=[{"role": "user", "content": "Why is the sky blue?"}],
)
print(response.choices[0].message.content)

In your app code, invoke OpenAI:

// main.ts
import OpenAI from "openai";

// set OPENAI_API_KEY in environment, or pass it in arguments
const openai = new OpenAI();

openai.chat.completions
  .create({
    model: "gpt-4o",
    messages: [{ role: "user", content: "Write a haiku." }],
  })
  .then((response) => {
    console.log(response.choices[0].message.content);
  })
  // for demonstration purposes, keep the node process alive long
  // enough for BatchSpanProcessor to flush Trace to Phoenix
  // with its default flush time of 5 seconds
  .then(() => new Promise((resolve) => setTimeout(resolve, 6000)));

View your Traces in Phoenix

You should now see traces in Phoenix!

Learn More:

Tracing Concepts

Tracing in Phoenix

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Last updated 18 days ago

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