OpenTelemetry provides a standardized way to collect and export telemetry data from your Next.js apps. This guide walks you through the process of configuring OpenTelemetry in a Next.js app to send traces to Axiom using the OpenTelemetry SDK.

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Prerequisites

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Send data from new project

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Initial setup

  1. Create a new app with the default settings using the Next.js documentation.
  2. Run the following command to install the dependencies: 
    npm install @opentelemetry/exporter-trace-otlp-http @opentelemetry/sdk-trace-node @opentelemetry/sdk-node @opentelemetry/resources
  3. Create an instrumentation.ts file in the src folder of your project with the following content:
    /src/instrumentation.ts
    import { OTLPTraceExporter } from "@opentelemetry/exporter-trace-otlp-http";
import type { Resource } from "@opentelemetry/resources";
import { resourceFromAttributes } from "@opentelemetry/resources";
import { NodeSDK } from "@opentelemetry/sdk-node";
import { SimpleSpanProcessor } from "@opentelemetry/sdk-trace-node";
import { ATTR_SERVICE_NAME } from "@opentelemetry/semantic-conventions";

export function register() {
  const sdk = new NodeSDK({
    resource: resourceFromAttributes({
      [ATTR_SERVICE_NAME]: "nextjs-otel-example",
    }) as Resource,
    spanProcessor: new SimpleSpanProcessor(
      new OTLPTraceExporter({
        url: `https://${process.env.AXIOM_DOMAIN}/v1/traces`,
        headers: {
          Authorization: `Bearer ${process.env.API_TOKEN}`,
          "X-Axiom-Dataset": `${process.env.DATASET_NAME}`,
        },
      })
    ),
  });

  sdk.start();
}
  4. Add the AXIOM_DOMAIN, API_TOKEN, and DATASET_NAME environment variables to your .env file. For example: 
    AXIOM_DOMAIN=api.axiom.co
API_TOKEN=xaat-123
DATASET_NAME=my-dataset

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Update root layout

In the /src/app/layout.tsx file, import and call the register function from the instrumentation module:
/src/app/layout.tsx
import { register } from '../instrumentation';

register();

export default function RootLayout({ children }: { children: React.ReactNode }) {
  return (
    <html lang="en">
      <body>{children}</body>
    </html>
  );
}
This file sets up the root layout for your Next.js app and initializes the OpenTelemetry instrumentation by calling the register function.

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Update compiler options

Add the following options to your tsconfig.json file to ensure compatibility with OpenTelemetry and Next.js:
/tsconfig.json
{
  "compilerOptions": {
    "target": "ES2017",
    "lib": ["dom", "dom.iterable", "esnext"],
    "allowJs": true,
    "skipLibCheck": true,
    "strict": true,
    "noEmit": true,
    "esModuleInterop": true,
    "module": "esnext",
    "moduleResolution": "bundler",
    "resolveJsonModule": true,
    "isolatedModules": true,
    "jsx": "preserve",
    "incremental": true,
    "plugins": [
      {
        "name": "next"
      }
    ],
    "paths": {
      "@/*": ["./src/*"]
    }
  },
  "include": ["next-env.d.ts", "**/*.ts", "**/*.tsx", ".next/types/**/*.ts"],
  "exclude": ["node_modules"]
}
This file configures the TypeScript compiler options for your Next.js app.

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Observe traces in Axiom

Use the following command to run your Next.js app with OpenTelemetry instrumentation in development mode: 
npm run dev
This command starts the Next.js development server, and the OpenTelemetry instrumentation automatically collects traces. As you interact with your app, traces are sent to Axiom where you can monitor and analyze your app’s performance and behavior. In Axiom, go to the Stream tab and click your dataset. This page displays the traces sent to Axiom and lets you monitor and analyze your app’s performance and behavior. Go to the Dashboards tab and click OpenTelemetry Traces. This pre-built traces dashboard provides further insights into the performance and behavior of your app.

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Send data from existing project

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Manual instrumentation

Manual instrumentation allows you to create, configure, and manage spans and traces, providing detailed control over telemetry data collection at specific points within the app.
  1. Set up and retrieve a tracer from the OpenTelemetry API. This tracer starts and manages spans within your app components or API routes.
import { trace } from '@opentelemetry/api';
const tracer = trace.getTracer('nextjs-app');
  1. Manually start a span at the beginning of significant operations or transactions within your Next.js app and ensure you end it appropriately. This approach is for tracing specific custom events or operations not automatically captured by instrumentations.
const span = tracer.startSpan('operationName');
try {
  // Perform your operation here
} finally {
  span.end();
}
  1. Enhance the span with additional information such as user details or operation outcomes, which can provide deeper insights when analyzing telemetry data.
span.setAttribute('user_id', userId);
span.setAttribute('operation_status', 'success');

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Automatic instrumentation

Automatic instrumentation uses the capabilities of OpenTelemetry to automatically capture telemetry data for standard operations such as HTTP requests and responses.
  1. Use the OpenTelemetry Node SDK to configure your app to automatically instrument supported libraries and frameworks. Set up NodeSDK in an instrumentation.ts file in your project.
/src/instrumentation.ts
import { NodeSDK } from '@opentelemetry/sdk-node';
import { OTLPTraceExporter } from '@opentelemetry/exporter-trace-otlp-http';

export function register() {
  const sdk = new NodeSDK({
    resource: new Resource({ [SEM_RESOURCE_ATTRIBUTES.SERVICE_NAME]: 'nextjs-app' }),
    spanProcessor: new BatchSpanProcessor(
      new OTLPTraceExporter({
        url: `https://${process.env.AXIOM_DOMAIN}/v1/traces`,
        headers: {
          Authorization: `Bearer ${process.env.API_TOKEN}`,
          'X-Axiom-Dataset': `${process.env.DATASET_NAME}`,
        },
      })
    ),
  });

  sdk.start();
}
  1. Include necessary OpenTelemetry instrumentation packages to automatically capture telemetry from Node.js libraries like HTTP and any other middlewares used by Next.js.
  2. Call the register function from the instrumentation.ts within your app startup file or before your app starts handling traffic to initialize the OpenTelemetry instrumentation. 
// In pages/_app.js or an equivalent entry point
import { register } from '../instrumentation';
register();

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Reference

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List of OpenTelemetry trace fields

Field CategoryField NameDescription
General Trace Information
_rowIdUnique identifier for each row in the trace data.
_sysTimeSystem timestamp when the trace data was recorded.
_timeTimestamp when the actual event being traced occurred.
trace_idUnique identifier for the entire trace.
span_idUnique identifier for the span within the trace.
parent_span_idUnique identifier for the parent span within the trace.
HTTP Attributes
attributes.http.methodHTTP method used for the request.
attributes.http.status_codeHTTP status code returned in response.
attributes.http.routeRoute accessed during the HTTP request.
attributes.http.targetSpecific target of the HTTP request.
Custom Attributes
attributes.custom[“next.route”]Custom attribute defining the Next.js route.
attributes.custom[“next.rsc”]Indicates if React Server Components are used.
attributes.custom[“next.span_name”]Custom name of the span within Next.js context.
attributes.custom[“next.span_type”]Type of the Next.js span, describing the operation context.
Resource Process Attributes
resource.process.pidProcess ID of the Node.js app.
resource.process.runtime.descriptionDescription of the runtime environment. For example, Node.js.
resource.process.runtime.nameName of the runtime environment. For example, nodejs.
resource.process.runtime.versionVersion of the runtime environment For example, 18.17.0.
resource.process.executable.nameExecutable name running the process. For example, next-server.
Resource Host Attributes
resource.host.archArchitecture of the host machine. For example, arm64.
resource.host.nameName of the host machine. For example, MacBook-Pro.local.
Operational Details
durationTime taken for the operation.
kindType of span (for example, server, internal).
nameName of the span, often a high-level title for the operation.
Scope Attributes
scope.nameName of the scope for the operation. For example, next.js.
scope.versionVersion of the scope. For example, 0.0.1.
Service Attributes
service.nameName of the service generating the trace. For example, nextjs-app.
Telemetry SDK Attributes
telemetry.sdk.languageLanguage of the telemetry SDK. For example, nodejs.
telemetry.sdk.nameName of the telemetry SDK. For example, opentelemetry.
telemetry.sdk.versionVersion of the telemetry SDK. For example, 1.23.0.

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List of imported libraries

@opentelemetry/api The core API for OpenTelemetry in JavaScript, providing the necessary interfaces and utilities for tracing, metrics, and context propagation. In the context of Next.js, it allows developers to manually instrument custom spans, manipulate context, and access the active span if needed. @opentelemetry/exporter-trace-otlp-http This exporter enables your Next.js app to send trace data over HTTP to any backend that supports the OTLP (OpenTelemetry Protocol), such as Axiom. Using OTLP ensures compatibility with a wide range of observability tools and standardizes the data export process. @opentelemetry/resources This defines the Resource which represents the entity producing telemetry. In Next.js, Resources can be used to describe the app (for example, service name, version) and are attached to all exported telemetry, aiding in identifying data in backend systems. @opentelemetry/sdk-node The OpenTelemetry SDK for Node.js which provides a comprehensive set of tools for instrumenting Node.js apps. It includes automatic instrumentation for popular libraries and frameworks, as well as APIs for manual instrumentation. In the Next.js setup, it’s used to configure and initialize the OpenTelemetry SDK. @opentelemetry/sdk-trace-node This package provides the Node.js-specific implementation of the OpenTelemetry Tracing SDK. It includes the core components needed to create and manage spans, as well as utilities for automatic and manual instrumentation in Node.js environments. In a Next.js application, it works alongside @opentelemetry/sdk-node to give finer control over the tracing pipeline. For example, configuring span processors, sampling strategies, or custom span exporters directly for trace data. It’s useful when you need more granular control over tracing behavior beyond the default SDK configuration. @opentelemetry/semantic-conventions A set of standard attributes and conventions for describing resources, spans, and metrics in OpenTelemetry. By adhering to these conventions, your Next.js app’s telemetry data becomes more consistent and interoperable with other OpenTelemetry-compatible tools and systems.