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An Introduction to OpenTelemetry JavaScript

By: HitSubscribe
  |  March 11, 2024
An Introduction to OpenTelemetry JavaScript

Monitoring and observing application performance is a cornerstone for maintaining robust and efficient systems in the ever-evolving development landscape. One key player in this domain is OpenTelemetry. This post provides a comprehensive tutorial and unpacks what OpenTelemetry is, its applications and integration into the JavaScript ecosystem.

What is OpenTelemetry?

OpenTelemetry is an open-source observability framework that provides standardized tools and techniques for collecting and exporting telemetry data – such as metrics, logs and traces – from applications and services. A project under the Cloud Native Computing Foundation (CNCF), OpenTelemetry underscores CNCF community-driven development and relevance in contemporary cloud-native architectures.

We can summarize the purpose of OpenTelemetry as the following:

  • Unified Observability: OpenTelemetry offers a single set of APIs, libraries, agents, and instrumentation that work across various platforms and languages, promoting a unified approach to observability.
  • Tracing, Metrics, and Logging: OpenTelemetry combines three critical aspects of observability:
    • Tracing: Capturing the journey of a request through various services is essential for understanding performance issues and service dependencies.
    • Metrics: Collecting numerical data that reflects the state of a system at a specific point in time, which is useful for monitoring and alerting.
    • Logging: Recording textual information about events within an application is vital for debugging and detailed analysis.
  • Simplifying Observability: OpenTelemetry simplifies the process of instrumenting applications, making it easier for developers to embed observability into their codebase without locking into a specific vendor or tool.

Key Uses of OpenTelemetry

  • Performance Monitoring: By providing detailed traces and metrics, OpenTelemetry helps identify performance bottlenecks, understand system throughput, and ensure that applications meet performance objectives.
  • Error Detection and Debugging: Traces and logs enable developers to track down errors and issues, understand root causes, and resolve efficiently.
  • Service Optimization: With insights from telemetry data, services can be optimized for better resource utilization, response times, and overall user experience.
  • Compliance and Security: Logging and tracing data can be used for audit trails, ensuring compliance with various regulations and enhancing security monitoring.

OpenTelemetry forms the backbone of modern application observability, providing essential tools for developers and organizations to gain insights into their applications’ performance and health. With standardization across different environments and programming languages, OpenTelemetry is an indispensable part of the cloud-native ecosystem.

Now, let’s explore how OpenTelemetry is specifically implemented and utilized in JavaScript.

What is OpenTelemetry for JavaScript?

OpenTelemetry for JavaScript is an observability framework for collecting, processing and exporting telemetry data from JavaScript applications. It’s an integral part of the OpenTelemetry project, which seeks to provide standardized tools across various programming languages for consistent observability practices. 

OpenTelemetry’s Role in Application Monitoring

The primary use of OpenTelemetry is to gather insights into application performance and behavior. OpenTelemetry tracks requests as they flow through various services, helping developers and system administrators understand system dependencies, diagnose bottlenecks and maintain overall system health. This level of insight is crucial for modern, distributed systems where complexity can make pinpointing issues challenging.

Core Components

Understanding the core components of OpenTelemetry for Javascript is crucial in leveraging its full potential. These components combine to provide a comprehensive telemetry data collection, processing, and exporting solution in JavaScript applications. Let’s dive into each of these components: 

API (Application Programming Interface):

The OpenTelemetry API is a set of interfaces and no-operation implementations that defines how developers interact with the observability framework. The API enables creating and managing traces, metrics, and context propagation interfaces, but the design ensures that if OpenTelemetry is not enabled or incorrectly configured, the application will still function correctly. This design feature is crucial for maintaining application stability and avoiding dependencies on the OpenTelemetry implementation.

SDK (Software Development Kit):

The SDK is the implementation of the API and where the actual functionality of OpenTelemetry resides. By providing default implementations for collecting, processing, and exporting telemetry data, the SDK supports managing span processors, exporters and context propagation.

Developers can configure the SDK to fine-tune its behavior, like setting up batching, sampling, and processing strategies for telemetry data. The SDK also supports extensibility, allowing developers to plug in custom components, like proprietary exporters or span processors, to suit specific needs.


Instrumentation libraries are a critical component of the OpenTelemetry ecosystem. They automatically capture telemetry data from applications and their libraries. These libraries can instrument standard libraries and frameworks like Express, MongoDB, or HTTP clients, capturing valuable telemetry data without requiring developers to write additional code.

Auto-instrumentation simplifies the process of data collection, ensuring consistent and comprehensive data is captured across different parts of an application. These instrumentations cover a wide range of popular libraries and frameworks for JavaScript, simplifying the integration of OpenTelemetry into existing projects.


Exporters in OpenTelemetry are responsible for sending the collected telemetry data to various backend systems for analysis and monitoring. Different exporters are available depending on the type of telemetry data and the backend system. For instance, there are trace, metric and log exporters. Standard exporters include those for Prometheus (for metrics), Jaeger and Zipkin (for tracing) and various cloud provider-specific exporters (like AWS X-Ray and Google Cloud Trace).

Exporter configuration is critical in setting up OpenTelemetry and determines how and where telemetry data is made available for analysis.

Setting Up OpenTelemetry in JavaScript

Setting up OpenTelemetry in a JavaScript project involves vital steps, from installation to configuration and data exportation.


A basic understanding of JavaScript and Node.js is necessary. For beginners, resources like “5 Key Tips for Beginners Learning JavaScript” provide a good starting point.


Install OpenTelemetry packages using npm:

npm install @opentelemetry/api @opentelemetry/sdk-trace-base @opentelemetry/exporter-trace-otlp-http

Basic Configuration

Initialize the Tracer:

Initialize and register the tracer provider to start tracing operations.

const { BasicTracerProvider, ConsoleSpanExporter, SimpleSpanProcessor } = require('@opentelemetry/sdk-trace-base');
const provider = new BasicTracerProvider();

provider.addSpanProcessor(new SimpleSpanProcessor(new ConsoleSpanExporter()));



Utilize auto-instrumentation libraries for common frameworks to simplify telemetry data collection.

// Example for Express.js
const { ExpressInstrumentation } = require('@opentelemetry/instrumentation-express');

provider.addSpanProcessor(new ExpressInstrumentation());

Data Exporting:

Configure an exporter to send telemetry data to your chosen backend.

const { OTLPTraceExporter } = require('@opentelemetry/exporter-trace-otlp-http');

provider.addSpanProcessor(new SimpleSpanProcessor(new OTLPTraceExporter()));

OpenTelemetry JavaScript SDKs and APIs

SDKs for Tracing and Metrics

The OpenTelemetry JavaScript SDKs provide robust tools for collecting and exporting telemetry data. The SDKs support multiple forms of telemetry, including tracing and metrics, allowing for a comprehensive overview of application performance.

Context API

The Context API is crucial in maintaining state and propagating data across asynchronous operations in JavaScript applications. The API ensures that the telemetry data is consistent and accurately represents the application’s behavior and performance.

Auto-Instrumentation Libraries

Auto-instrumentation libraries simplify collecting telemetry data by automatically hooking into popular frameworks and libraries. This automation reduces the manual effort required for instrumentation and ensures a standard level of observability across different parts of an application. 

The Future Outlook of OpenTelemetry in JavaScript

The future of OpenTelemetry in JavaScript is promising. As JavaScript continues to dominate both frontend and backend development, the role of OpenTelemetry in providing insights and understanding application performance becomes increasingly vital. 

JavaScript’s Suitability for OpenTelemetry

JavaScript’s event-driven and non-blocking architecture is particularly well-suited for integrating with OpenTelemetry. Unlike languages that rely heavily on multi-threading, JavaScript’s single-threaded nature simplifies context management, which is a critical aspect of distributed tracing. 

Comparisons with Other Languages

While OpenTelemetry offers SDKs for various programming languages, the integration in JavaScript is unique due to the language’s ubiquity and architectural characteristics. This simplifies the implementation of observability features, especially in a Node.js environment where backend applications can benefit significantly from real-time performance data. 

Addressing Common Concerns

OpenTelemetry vs. Prometheus

Distinguishing the differences between OpenTelemetry from tools like Prometheus is crucial. While Prometheus specializes in metrics storage and querying, OpenTelemetry provides a broader scope, encompassing tracing, logging and metrics collection. OpenTelemetry can feed data into Prometheus, but OpenTelemetry capabilities extend to a broader range of observability functions.

Disadvantages of OpenTelemetry

Despite advantages, OpenTelemetry does have its challenges. The initial setup and configuration can be complex, particularly for those new to observability concepts. Additionally, as an evolving project, some features and integrations still need to be developed, whichcan lead to potential inconsistencies and gaps in documentation.


In conclusion, OpenTelemetry JavaScript emerges as a robust and versatile tool in observability, offering deep insights into application performance. For developers venturing into observability, resources like “Node.js Logging Tutorial”and “Optimized: Using A JavaScript (JS) Profiler For Improved Performance” can provide additional guidance. Java developers can also find relevant insights in the “Retrace Set Up Guide for Java” OpenTelemetry JavaScript is not just a tool; it’s a gateway to understanding and optimizing your applications. With OpenTelemetry JavaScript, you can ensure applications perform at their best in the ever-demanding landscape of modern web development.

This post was written by Juan Reyes. As an entrepreneur, skilled engineer, and mental health champion, Juan pursues sustainable self-growth, embodying leadership, wit, and passion. With over 15 years of experience in the tech industry, Juan has had the opportunity to work with some of the most prominent players in mobile development, web development, and e-commerce in Japan and the US.

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