Datadog Capture Server

A local proxy server that captures and inspects Datadog SDK requests before forwarding them to the real Datadog intake. Useful for debugging, development, and benchmarking compression algorithms.

Features

• Captures all Datadog SDK features: RUM, Logs, Traces, Session Replay, Profiling, Feature Flags
• Web UI for browsing and inspecting captured requests
• Forwards requests to real Datadog intake
• Decompresses zstd/gzip bodies for viewing
• SQLite storage for persistence
• Export captured data as JSON

Quick Start

# Install dependencies
npm install

# Start the server
npm start

# Open Web UI
open http://localhost:8080/ui

Endpoints

SDK Feature	Local Endpoint
RUM	POST /api/v2/rum
Logs	POST /api/v2/logs
Traces	POST /api/v2/spans
Session Replay	POST /api/v2/replay
Profiling	POST /api/v2/profile
Feature Flags (exposures)	POST /api/v2/exposures
Feature Flags (assignments)	GET /flags/*

Android Configuration

1. Network Security Config

Allow cleartext HTTP for the local server. Create res/xml/network_security_config.xml:

<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
    <domain-config cleartextTrafficPermitted="true">
        <domain includeSubdomains="false">10.0.2.2</domain>
    </domain-config>
</network-security-config>

Reference it in AndroidManifest.xml:

<application android:networkSecurityConfig="@xml/network_security_config" ...>

2. Configure SDK Custom Endpoints

// For emulator, use 10.0.2.2 (maps to host machine's localhost)
private val localServerUrl = "http://10.0.2.2:8080"

val rumConfig = RumConfiguration.Builder(appId)
    .useCustomEndpoint("$localServerUrl/api/v2/rum")
    .build()

val logsConfig = LogsConfiguration.Builder()
    .useCustomEndpoint("$localServerUrl/api/v2/logs")
    .build()

val srConfig = SessionReplayConfiguration.Builder(sampleRate)
    .useCustomEndpoint("$localServerUrl/api/v2/replay")
    .build()

val traceConfig = TraceConfiguration.Builder()
    .useCustomEndpoint("$localServerUrl/api/v2/spans")
    .build()

Web UI

Access the Web UI at http://localhost:8080/ui to:

• View all captured requests
• Filter by feature type
• Inspect request headers and body
• See forward status
• Export data for analysis

API

• GET /ui-api/requests - List all requests (supports ?feature=rum&limit=100)
• GET /ui-api/requests/:id - Get request details
• GET /ui-api/stats - Get capture statistics
• DELETE /ui-api/requests - Clear all captured data
• GET /ui-api/export - Export all data as JSON