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LangfuseExporter

Sends AI tracing data to Langfuse for observability.

Constructor​

new LangfuseExporter(config: LangfuseExporterConfig)

LangfuseExporterConfig​

interface LangfuseExporterConfig {
  publicKey?: string;
  secretKey?: string;
  baseUrl?: string;
  realtime?: boolean;
  logLevel?: "debug" | "info" | "warn" | "error";
  options?: any;
}

Methods​

exportEvent​

async exportEvent(event: AITracingEvent): Promise<void>

Exports a tracing event to Langfuse.

export​

async export(spans: ReadOnlyAISpan[]): Promise<void>

Batch exports spans to Langfuse.

shutdown​

async shutdown(): Promise<void>

Flushes pending data and shuts down the client.

Usage​

import { LangfuseExporter } from "@mastra/langfuse";

const exporter = new LangfuseExporter({
  publicKey: process.env.LANGFUSE_PUBLIC_KEY,
  secretKey: process.env.LANGFUSE_SECRET_KEY,
  baseUrl: "https://cloud.langfuse.com",
  realtime: true,
});

Span Mapping​

  • Root spans → Langfuse traces
  • MODEL_GENERATION spans → Langfuse generations
  • All other spans → Langfuse spans
  • Event spans → Langfuse events

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