OpenRouter

OpenRouter lets you call models from many providers through a single API.

TypeScript
Python

If you’re using OpenRouter’s agent toolkit package (@openrouter/agent), see OpenRouter Agent.

Setup

Install packages

# pnpm
pnpm add braintrust @openrouter/sdk
# npm
npm install braintrust @openrouter/sdk

Set environment variables

.env

OPENROUTER_API_KEY=<your-openrouter-api-key>
BRAINTRUST_API_KEY=<your-braintrust-api-key>

# If you are self-hosting Braintrust, set the URL of your hosted dataplane
# BRAINTRUST_API_URL=<your-braintrust-api-url>

Auto-instrumentation

Braintrust provides automatic tracing for OpenRouter calls. This is the recommended setup for most projects.

import { initLogger } from "braintrust";
import { OpenRouter } from "@openrouter/sdk";

initLogger({
  projectName: "My Project",
  apiKey: process.env.BRAINTRUST_API_KEY,
});

const client = new OpenRouter({ apiKey: process.env.OPENROUTER_API_KEY });

const response = await client.chat.send({
  chatRequest: {
    model: "openai/gpt-5-mini",
    messages: [{ role: "user", content: "What is observability?" }],
  },
});

Run with the import hook:

node --import braintrust/hook.mjs app.js

The auto-instrumentation example uses plain JavaScript so node --import can run the file directly. The Braintrust APIs work the same in TypeScript projects — compile your TypeScript to JavaScript, then run the compiled file with the import hook.

If you’re using a bundler, see Trace LLM calls for plugin and loader setup.

Manual instrumentation

Trace an OpenRouter client explicitly by wrapping it with wrapOpenRouter.

import { initLogger, wrapOpenRouter } from "braintrust";
import { OpenRouter } from "@openrouter/sdk";

initLogger({
  projectName: "My Project",
  apiKey: process.env.BRAINTRUST_API_KEY,
});

const client = wrapOpenRouter(
  new OpenRouter({ apiKey: process.env.OPENROUTER_API_KEY }),
);

const response = await client.chat.send({
  chatRequest: {
    model: "openai/gpt-5-mini",
    messages: [{ role: "user", content: "What is observability?" }],
  },
});

What Braintrust traces

For the @openrouter/sdk package, Braintrust traces:

Chat completions via chat.send(), including streaming
Embeddings via embeddings.generate()
Reranking via rerank.rerank(), with topN and document count in metadata and each result captured as { index, relevance_score }
Responses API via beta.responses.send(), including streaming

Setup

Install packages

pip install braintrust openrouter

Set environment variables

.env

OPENROUTER_API_KEY=<your-openrouter-api-key>
BRAINTRUST_API_KEY=<your-braintrust-api-key>

Auto-instrumentation

Braintrust provides automatic tracing for OpenRouter calls. This is the recommended setup for most projects.

import os

import braintrust

braintrust.auto_instrument()
braintrust.init_logger(project="My Project")

from openrouter import OpenRouter

client = OpenRouter(api_key=os.environ["OPENROUTER_API_KEY"])

response = client.chat.send(
    model="openai/gpt-5-mini",
    messages=[{"role": "user", "content": "What is observability?"}],
)

Manual instrumentation

Trace the OpenRouter Python SDK by wrapping the client with wrap_openrouter().

import os

from braintrust import init_logger, wrap_openrouter
from openrouter import OpenRouter

init_logger(project="My Project")

client = wrap_openrouter(OpenRouter(api_key=os.environ["OPENROUTER_API_KEY"]))

response = client.beta.responses.send(
    model="openai/gpt-5-mini",
    input="Summarize tracing in one sentence.",
)

# Response shape varies; adjust indexing for your model and request.
print(response.output[1].content[0].text)

OpenAI-compatible endpoint

If your app already uses the OpenAI Python SDK with OpenRouter’s OpenAI-compatible endpoint, keep that setup and use wrap_openai().

import os

from braintrust import init_logger, wrap_openai
from openai import OpenAI

init_logger(project="My Project")

client = wrap_openai(
    OpenAI(
        base_url="https://openrouter.ai/api/v1",
        api_key=os.environ["OPENROUTER_API_KEY"],
    )
)

response = client.responses.create(
    model="openai/gpt-5-mini",
    input="Explain routing in one sentence.",
)

print(response.output_text)

What Braintrust traces

For the openrouter SDK, Braintrust traces:

Chat completions via chat.send() and send_async(), including streaming
Embeddings via embeddings.generate() and the async variant
Responses API calls via beta.responses.send() and send_async(), including streaming

AI providers

SDKs

Developer tools

Setup

Auto-instrumentation

Manual instrumentation

What Braintrust traces

Setup

Auto-instrumentation

Manual instrumentation

OpenAI-compatible endpoint

What Braintrust traces

Resources

​Setup

​Auto-instrumentation

​Manual instrumentation

​What Braintrust traces

​Setup

​Auto-instrumentation

​Manual instrumentation

​OpenAI-compatible endpoint

​What Braintrust traces

​Resources

Setup

Auto-instrumentation

Manual instrumentation

What Braintrust traces

Setup

Auto-instrumentation

Manual instrumentation

OpenAI-compatible endpoint

What Braintrust traces

Resources