Firebase Genkit Integration

Export Firebase Genkit Go traces to LangWatch to observe flows, models, and tools for AI agent evaluation.

Firebase Genkit for Go is OpenTelemetry-native: it already emits its own gen_ai.* spans for flows, models and tools onto the global OpenTelemetry tracer provider. The LangWatch Genkit package does no body parsing; it registers a LangWatch span processor on the tracer provider Genkit’s spans flow through, so whatever Genkit records (model, token usage, prompt/completion and tool data) is exported to LangWatch.

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Installation

go get github.com/langwatch/langwatch/sdks/go
go get github.com/langwatch/langwatch/sdks/go/instrumentation/genkit
go get github.com/firebase/genkit/go

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Usage

Set the LANGWATCH_API_KEY environment variable before running.

Register LangWatch once, after genkit.Init:

package main

import (
	"context"
	"log"

	"github.com/firebase/genkit/go/genkit"
	"github.com/firebase/genkit/go/plugins/googlegenai"

	lwgenkit "github.com/langwatch/langwatch/sdks/go/instrumentation/genkit"
)

func main() {
	ctx := context.Background()

	g := genkit.Init(ctx, genkit.WithPlugins(&googlegenai.GoogleAI{}))

	// Export Genkit's OTEL spans to LangWatch (reads LANGWATCH_API_KEY from env).
	if err := lwgenkit.RegisterLangWatch(g); err != nil {
		log.Fatalf("failed to register LangWatch: %v", err)
	}

	// Define and run flows as usual; their spans are exported to LangWatch.
}

RegisterLangWatch reads LANGWATCH_API_KEY (and LANGWATCH_ENDPOINT) from the environment by default. To forward exporter options (API key, endpoint, data capture, filters), pass WithExporterOptions:

import langwatch "github.com/langwatch/langwatch/sdks/go"

lwgenkit.RegisterLangWatch(g,
	lwgenkit.WithExporterOptions(
		langwatch.WithAPIKey("sk-lw-..."),
		langwatch.WithDataCapture(langwatch.DataCaptureNone), // structure/metrics only
	),
)

LangWatch captures whatever gen_ai.* attributes Genkit records; there is no extra parsing in this package. If you build your own sdktrace.TracerProvider, use lwgenkit.SpanProcessor(opts...) to obtain the processor and register it yourself (Genkit reads the global tracer provider).

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Check it worked

Run one of your flows. Then open your project in LangWatch: a new trace appears in the traces list within a few seconds, with the spans Genkit recorded for the flow and its model calls.

If no trace appears, check that LANGWATCH_API_KEY is set in the environment the program runs in.

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Related

• Go Integration Guide - Setup, manual spans, data capture and the REST client
• Go SDK API Reference - Instrumentation options and data capture
• Capturing Evaluations & Guardrails - Log evaluations and implement guardrails