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

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Installation

npm install @braintrust/otel

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Quick start

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());

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API Reference

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Functions

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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.

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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.

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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.

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isRootSpan

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

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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.

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resetOtelCompat

resetOtelCompat function.

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setupOtelCompat

setupOtelCompat function.

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Classes

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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)

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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)

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Source Code

For the complete source code and additional examples, visit the Braintrust JavaScript SDK repository.