---
id: ddapm-test-agent
version: "1.65.0"
license: BSD 3
license_treatment: permissive
maintenance: active
---

# ddapm-test-agent — Test agent for Datadog APM client libraries

License: permissive · Maintenance: active · Downloads: 3.3M/mo

## What it is and what it does

The Datadog APM test agent is a mock server that emulates the endpoints of the production Datadog agent, allowing developers to test APM client libraries in isolation without a running Datadog infrastructure. It listens on configurable ports for HTTP traces (8126), OTLP HTTP (4318), and OTLP gRPC (4317), and provides a web UI for inspecting received traces and managing test sessions.

The agent performs trace invariant checks (trace count headers, tracer version headers, content length validation), stores all submitted data for retrieval via API, and supports snapshot testing for characterization-based regression detection. It can proxy requests to a real Datadog agent or forward LLM observability events directly to Datadog. It also records and replays third-party API calls (OpenAI, Azure OpenAI, DeepSeek) for reproducible testing.

Use it for:

- Test Datadog APM client libraries locally without deploying a full Datadog agent or cloud infrastructure.
- Validate trace structure and metadata compliance in integration tests using snapshot testing.
- Record and replay third-party API interactions (OpenAI, Azure OpenAI, DeepSeek) for deterministic LLM observability testing.
- Debug trace payload issues by inspecting received requests and trace trees via the web UI.
- Proxy traces to a real Datadog agent for selective validation while testing client library changes.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Emulates Datadog APM agent endpoints to test Datadog APM client libraries, providing trace validation, snapshot testing, and optional proxying to a real Datadog agent.

Yes. The package is actively maintained, has no known vulnerabilities, and is purpose-built for testing Datadog APM integrations. Install it if you develop or maintain a Datadog APM client library or need to validate trace behavior in CI/CD. The low install friction and permissive license make it a straightforward addition to test infrastructure.

## Install

pip install ddapm-test-agent
uv add ddapm-test-agent
poetry add ddapm-test-agent

## Installing ddapm-test-agent

Before you install: Low friction installation with a pure Python wheel. Active maintenance with a release on 2026-08-14. Requires 13 runtime dependencies including aiohttp, protobuf, and grpcio, which are standard libraries for HTTP and gRPC services.

License in practice: BSD 3 permissive license allows use in commercial and open-source projects with minimal restrictions, requiring only preservation of copyright and license notices.

Quickstart:

pip install ddapm-test-agent

ddapm-test-agent --port=8126 --otlp-http-port=4318 --otlp-grpc-port=4317 --web-ui-port=8080

Binds to 127.0.0.1 by default; pass --host 0.0.0.0 to accept connections from other hosts.

Verify before relying:

- Whether the Web UI is production-ready or remains experimental in current releases.
- Performance characteristics when handling high-volume trace payloads or many concurrent sessions.
- Compatibility with APM client libraries beyond the Datadog ecosystem.

## Package facts

- License: BSD 3 (permissive)
- Python support: supports_current
- Install friction: low
- Maintenance: active
- Downloads: 3.3M/month (top 5,000 on PyPI)
- Known vulnerabilities: none known

## Tags

datadog apm testing, trace validation testing, apm client library testing, datadog agent mock, snapshot testing traces, otlp endpoint testing, distributed trace testing, apm-testing, trace-validation, datadog-integration

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