Go tracing installation

Install OpenTelemetry packages

Required

For the complete SDK reference, see the OpenTelemetry Go docs.

Terminal
go get go.opentelemetry.io/otel
go get go.opentelemetry.io/otel/sdk
go get go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp

otlptracehttp is the OTLP HTTP/protobuf trace exporter. The otlptracegrpc module sends gRPC, so pick otlptracehttp to match this guide.

2
Get your project token
Required
You'll need your PostHog project token to authenticate trace requests. This is the same token you use for capturing events with the PostHog SDK.
Important: Use your project token which starts with phc_. Do not use a personal API key (which starts with phx_).
You can find your project token in Project settings.

Configure the SDK

Required

Set up the OpenTelemetry SDK to export spans to PostHog over OTLP HTTP. Use WithEndpointURL so the full /i/v1/traces path is sent as-is.

Go
package main

import (
    "context"

    "go.opentelemetry.io/otel"
    "go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
    "go.opentelemetry.io/otel/sdk/resource"
    sdktrace "go.opentelemetry.io/otel/sdk/trace"
    semconv "go.opentelemetry.io/otel/semconv/v1.41.0"
)

func initTracer(ctx context.Context) (*sdktrace.TracerProvider, error) {
    exporter, err := otlptracehttp.New(ctx,
        otlptracehttp.WithEndpointURL("https://us.i.posthog.com/i/v1/traces"),
        otlptracehttp.WithHeaders(map[string]string{
            "Authorization": "Bearer <ph_project_token>",
        }),
    )
    if err != nil {
        return nil, err
    }

    res, err := resource.New(ctx,
        resource.WithAttributes(semconv.ServiceName("my-service")),
    )
    if err != nil {
        return nil, err
    }

    tp := sdktrace.NewTracerProvider(
        sdktrace.WithBatcher(exporter),
        sdktrace.WithResource(res),
    )
    otel.SetTracerProvider(tp)
    return tp, nil
}

Call defer tp.Shutdown(ctx) in main so buffered spans flush on exit.

Alternatively, configure the exporter with environment variables and call otlptracehttp.New(ctx) with no options:

Terminal
OTEL_EXPORTER_OTLP_TRACES_ENDPOINT="https://us.i.posthog.com/i/v1/traces"
OTEL_EXPORTER_OTLP_TRACES_HEADERS="Authorization=Bearer <ph_project_token>"
OTEL_SERVICE_NAME="my-service"

Note: WithEndpoint sets only the host and defaults the path to /v1/traces. To send to the full /i/v1/traces path, use WithEndpointURL (or the per-signal OTEL_EXPORTER_OTLP_TRACES_ENDPOINT), as shown.

Create spans

Required

Wrap the operations you want to measure in spans, and attach attributes for context.

Go
import (
    "context"

    "go.opentelemetry.io/otel"
    "go.opentelemetry.io/otel/attribute"
)

var tracer = otel.Tracer("my-service")

func chargeCustomer(ctx context.Context, customerID string) error {
    ctx, span := tracer.Start(ctx, "charge-customer")
    defer span.End()

    span.SetAttributes(attribute.String("customer.id", customerID))
    // ... do work ...
    return nil
}

5
Test your setup
Recommended
Once everything is configured, confirm spans are reaching PostHog:
1. Run your application and trigger the instrumented code
2. Open the PostHog Tracing interface
3. Confirm your spans and traces appear
View your traces in PostHog

Next steps

Checkpoint

What you can do with your traces

Action	Description
Why you need distributed tracing	What a trace shows you that nothing else does
Explore traces	Read a trace as a waterfall to see where time goes
Filter spans	Narrow down by service, status, duration, and attributes
Propagate context	Pass trace context across services so spans join the same trace

View your traces in PostHog

Go tracing installation

Install OpenTelemetry packages

Get your project token

Configure the SDK

Create spans

Test your setup

Next steps

Community questions

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