Server Source code Package

Express

Turn-key HTTP event collection server with Express.js. Handles JSON POST events, pixel tracking (GET), CORS, and health checks.

Features

• Standalone or embedded: Start server automatically or integrate with existing Express app
• CORS support: Configurable cross-origin resource sharing
• Pixel tracking: 1x1 transparent GIF for GET requests
• Health checks: Built-in /health and /ready endpoints

Where This Fits

The Express Source is a server source in the walkerOS flow:

It receives events via HTTP (POST/GET) and forwards them to configured destinations.

Installation

Loading...

path setting renamed to paths

The path setting has been renamed to paths (array). The old path still works but is deprecated and will be removed in the next major version.

// Before (deprecated)
settings: { path: '/events' }

// After
settings: { paths: ['/events'] }

Quick start

Integrated

Standalone server

Loading...

App-Only Mode

Loading...

Bundled

Add to your flow.json sources:

Loading...

Server sources require platform-specific handlers. For containerized deployments, see Docker →.

See Bundled Mode setup → | CLI reference →

Configuration

Property	Type	Description	More
port	integer	HTTP server port to listen on. Use 0 for random available port. If not provided, server will not start (app only mode)
path	string	Deprecated: use paths instead
paths	Array<any>	Route paths to register. String shorthand registers GET+POST. RouteConfig allows per-route method control.
cors*	boolean | object	CORS configuration: false = disabled, true = allow all origins (default), object = custom configuration
status*	boolean	Enable health check endpoints (/health, /ready)

* Required fields

HTTP methods

Method	Endpoint	Description
POST	/collect	JSON event ingestion
GET	/collect	Pixel tracking (returns 1x1 GIF)
OPTIONS	/collect	CORS preflight
GET	/health	Liveness check
GET	/ready	Readiness check

Ingest Metadata

Extract request metadata (IP, user agent, headers) and forward it through the pipeline to transformers and destinations.

Loading...

Available Ingest Paths

Path	Description
ip	Client IP address
headers.*	HTTP headers (user-agent, origin, referer, etc.)
protocol	Request protocol (http/https)
method	HTTP method (GET, POST, etc.)
hostname	Request hostname
url	Full request URL

Advanced Mapping

Use walkerOS mapping features for complex extraction:

Loading...

Example request

Loading...