> ## Documentation Index
> Fetch the complete documentation index at: https://braintrust.dev/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# OpenTelemetry JS Integration

> OpenTelemetry JS Integration v0.2.0

The `@braintrust/otel` package provides OpenTelemetry integration for Braintrust tracing.

## Installation

<CodeGroup>
  ```bash npm theme={"theme":{"light":"github-light","dark":"github-dark-dimmed"}}
  npm install @braintrust/otel
  ```

  ```bash pnpm theme={"theme":{"light":"github-light","dark":"github-dark-dimmed"}}
  pnpm add @braintrust/otel
  ```
</CodeGroup>

## Quick start

```typescript theme={"theme":{"light":"github-light","dark":"github-dark-dimmed"}}
import { BraintrustSpanProcessor } from "@braintrust/otel";
import { NodeTracerProvider } from "@opentelemetry/sdk-trace-node";

// Add the Braintrust span processor
const provider = new NodeTracerProvider();
provider.addSpanProcessor(new BraintrustSpanProcessor());
```

## API Reference

### Functions

#### addParentToBaggage

Add braintrust.parent to OTEL baggage. This ensures that when using propagation inject() for distributed tracing, the braintrust.parent will be propagated via baggage to downstream services.

#### addSpanParentToBaggage

Copy braintrust.parent from span attribute to OTEL baggage. BraintrustSpanProcessor automatically sets braintrust.parent as a span attribute when OTEL spans are created within Braintrust contexts. This function copies that attribute to OTEL baggage so it propagates when using inject() for distributed tracing.

#### contextFromSpanExport

Create an OTEL context from a Braintrust span export string. Used for distributed tracing scenarios where a Braintrust span in one service needs to be the parent of an OTEL span in another service.

#### isRootSpan

Returns true if the span is a root span (no parent). Checks both parentSpanId (OTel 1.x) and parentSpanContext (OTel 2.x).

#### parentFromHeaders

Extract a Braintrust-compatible parent string from W3C Trace Context headers. This converts OTEL trace context headers (traceparent/baggage) into a format that can be passed as the 'parent' parameter to Braintrust's traced() method.

#### resetOtelCompat

resetOtelCompat function.

#### setupOtelCompat

setupOtelCompat function.

### Classes

#### BraintrustExporter

A trace exporter that sends OpenTelemetry spans to Braintrust. This exporter wraps the standard OTLP trace exporter and can be used with any OpenTelemetry setup, including @vercel/otel's registerOTel function, NodeSDK, or custom tracer providers. It can optionally filter spans to only send AI-related telemetry. Environment Variables: - BRAINTRUST\_API\_KEY: Your Braintrust API key. In Node.js, this can also be set in the nearest .env.braintrust file. - BRAINTRUST\_PARENT: Parent identifier (e.g., "project\_name:test") - BRAINTRUST\_API\_URL: Base URL for Braintrust API (defaults to [https://api.braintrust.dev](https://api.braintrust.dev))

#### BraintrustSpanProcessor

A span processor that sends OpenTelemetry spans to Braintrust. This processor uses a BatchSpanProcessor and an OTLP exporter configured to send data to Braintrust's telemetry endpoint. Span filtering is disabled by default but can be enabled with the filterAISpans option. Environment Variables: - BRAINTRUST\_API\_KEY: Your Braintrust API key. In Node.js, this can also be set in the nearest .env.braintrust file. - BRAINTRUST\_PARENT: Parent identifier (e.g., "project\_name:test") - BRAINTRUST\_API\_URL: Base URL for Braintrust API (defaults to [https://api.braintrust.dev](https://api.braintrust.dev))

## Source Code

For the complete source code and additional examples, visit the [Braintrust JavaScript SDK repository](https://github.com/braintrustdata/braintrust-sdk-javascript/tree/main/integrations/otel-js).