OpenRouter Integration

export LANGWATCH_API_KEY="your-langwatch-api-key"
export OPENROUTER_API_KEY="your-openrouter-api-key"

go get github.com/langwatch/langwatch/sdks/go
go get github.com/langwatch/langwatch/sdks/go/instrumentation/openai
go get github.com/openai/openai-go/v3

package main

import (
	"context"
	"log"
	"os"

	langwatch "github.com/langwatch/langwatch/sdks/go"
	otelopenai "github.com/langwatch/langwatch/sdks/go/instrumentation/openai"

	"github.com/openai/openai-go/v3"
	"github.com/openai/openai-go/v3/option"
	"go.opentelemetry.io/otel"
	semconv "go.opentelemetry.io/otel/semconv/v1.40.0"
	sdktrace "go.opentelemetry.io/otel/sdk/trace"
)

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

	// Set up the LangWatch exporter (reads LANGWATCH_API_KEY from env).
	exporter, err := langwatch.NewExporter(ctx)
	if err != nil {
		log.Fatalf("failed to create exporter: %v", err)
	}
	tp := sdktrace.NewTracerProvider(sdktrace.WithBatcher(exporter))
	otel.SetTracerProvider(tp)
	defer tp.Shutdown(ctx) // Critical: ensures traces are flushed.

	// Create an OpenRouter client via the OpenAI-compatible API.
	client := openai.NewClient(
		option.WithBaseURL("https://openrouter.ai/api/v1"),
		option.WithAPIKey(os.Getenv("OPENROUTER_API_KEY")),
		option.WithMiddleware(otelopenai.Middleware("my-app",
			otelopenai.WithGenAIProvider(semconv.GenAIProviderNameKey.String("openrouter")),
		)),
	)

	response, err := client.Chat.Completions.New(ctx, openai.ChatCompletionNewParams{
		Model: "anthropic/claude-sonnet-5",
		Messages: []openai.ChatCompletionMessageParamUnion{
			openai.UserMessage("Hello via OpenRouter!"),
		},
	})
	if err != nil {
		log.Fatalf("OpenRouter API call failed: %v", err)
	}

	log.Printf("Response: %s", response.Choices[0].Message.Content)
}