Best Application Performance Monitoring (APM) tools in 2025

# Download the latest OpenTelemetry Java agent (jar)
# https://github.com/open-telemetry/opentelemetry-java-instrumentation/releases
export OTEL_SERVICE_NAME=checkout-service
export OTEL_EXPORTER_OTLP_ENDPOINT=https://otlp.example.com
export OTEL_EXPORTER_OTLP_HEADERS="authorization=Bearer <TOKEN>"
export OTEL_TRACES_SAMPLER=parentbased_traceidratio
export OTEL_TRACES_SAMPLER_ARG=0.2   # 20% head sampling to start

java -javaagent:/path/opentelemetry-javaagent.jar \
     -Dotel.resource.attributes=deployment.environment=prod \
     -jar app.jar

# Install
npm i @opentelemetry/sdk-node @opentelemetry/auto-instrumentations-node \
      @opentelemetry/exporter-trace-otlp-grpc

// tracing.js
const { NodeSDK } = require('@opentelemetry/sdk-node');
const { getNodeAutoInstrumentations } = require('@opentelemetry/auto-instrumentations-node');
const { OTLPTraceExporter } = require('@opentelemetry/exporter-trace-otlp-grpc');

const exporter = new OTLPTraceExporter({
  url: process.env.OTEL_EXPORTER_OTLP_ENDPOINT, // e.g. https://otlp.example.com
  metadata: { Authorization: 'Bearer ' + process.env.OTLP_TOKEN }
});

const sdk = new NodeSDK({
  traceExporter: exporter,
  serviceName: process.env.OTEL_SERVICE_NAME || 'checkout-service',
  instrumentations: [getNodeAutoInstrumentations()]
});

sdk.start();

// index.js
require('./tracing');
require('./server');

# Install
pip install opentelemetry-distro opentelemetry-exporter-otlp

export OTEL_SERVICE_NAME=checkout-service
export OTEL_EXPORTER_OTLP_ENDPOINT=https://otlp.example.com
export OTEL_EXPORTER_OTLP_HEADERS="authorization=Bearer <TOKEN>"
export OTEL_TRACES_SAMPLER=parentbased_traceidratio
export OTEL_TRACES_SAMPLER_ARG=0.2

# Run auto-instrumented
opentelemetry-instrument --traces_exporter otlp --metrics_exporter none \
  gunicorn app:wsgi

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

import (
  "context"
  "go.opentelemetry.io/otel"
  "go.opentelemetry.io/otel/sdk/resource"
  "go.opentelemetry.io/otel/sdk/trace"
  "go.opentelemetry.io/otel/semconv/v1.24.0"
  "go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
)

func initTracer() func(context.Context) error {
  exp, _ := otlptracehttp.New(context.Background(),
    otlptracehttp.WithEndpointURL("https://otlp.example.com"),
    otlptracehttp.WithHeaders(map[string]string{"authorization":"Bearer TOKEN"}),
  )
  tp := trace.NewTracerProvider(
    trace.WithBatcher(exp),
    trace.WithResource(resource.NewWithAttributes(
      semconv.SchemaURL, semconv.ServiceName("checkout-service"),
    )),
  )
  otel.SetTracerProvider(tp)
  return tp.Shutdown
}

# install
dotnet add package OpenTelemetry.Extensions.Hosting
dotnet add package OpenTelemetry.Exporter.OpenTelemetryProtocol
dotnet add package OpenTelemetry.Instrumentation.AspNetCore

// Program.cs (.NET 8)
builder.Services.AddOpenTelemetry()
  .ConfigureResource(r => r.AddService("checkout-service"))
  .WithTracing(t => t
    .AddAspNetCoreInstrumentation()
    .AddHttpClientInstrumentation()
    .AddOtlpExporter(o => {
      o.Endpoint = new Uri("https://otlp.example.com");
      o.Headers = "authorization=Bearer <TOKEN>";
    })
  );