---
title: "Zero-code"
source: OpenTelemetry Documentation
source_url: https://github.com/open-telemetry/opentelemetry.io
licence: CC-BY-4.0
domain: engineering
subdomain: opentelemetry-docs
date_added: 2026-04-25
---

As [ops](/docs/getting-started/ops/) you might want to add observability to one
or more applications without having to edit the source. OpenTelemetry lets you
quickly gain some observability for a service without having to use the
OpenTelemetry API & SDK for
[code-based instrumentation](/docs/concepts/instrumentation/code-based).

![Zero Code](./zero-code.svg)

Zero-code instrumentation adds the OpenTelemetry API and SDK capabilities to
your application typically as an agent or agent-like installation. The specific
mechanisms involved may differ by language, ranging from bytecode manipulation,
monkey patching, or eBPF to inject calls to the OpenTelemetry API and SDK into
your application.

Typically, zero-code instrumentation adds instrumentation for the libraries
you're using. This means that requests and responses, database calls, message
queue calls, and so forth are what are instrumented. Your application's code,
however, is not typically instrumented. To instrument your code, you'll need to
use [code-based instrumentation](/docs/concepts/instrumentation/code-based).

Additionally, zero-code instrumentation lets you configure the
[Instrumentation Libraries](/docs/concepts/instrumentation/libraries) and
[exporters](/docs/concepts/components/#exporters) loaded.

You can configure zero-code instrumentation through environment variables and
other language-specific mechanisms, such as system properties or arguments
passed to initialization methods. To get started, you only need a service name
configured so that you can identify the service in the observability backend of
your choice.

Other configuration options are available, including:

- Data source specific configuration
- Exporter configuration
- Propagator configuration
- Resource configuration

Automatic instrumentation is available for the following languages:

- [.NET](/docs/zero-code/dotnet/)
- [Go](/docs/zero-code/go)
- [Java](/docs/zero-code/java/)
- [JavaScript](/docs/zero-code/js/)
- [PHP](/docs/zero-code/php/)
- [Python](/docs/zero-code/python/)
