Carto

Web-first Zenoh traffic inspector with desktop builds for Windows, macOS, and Linux

Inspect, filter, decode, and publish Zenoh messages in real time.

Carto is an open-source, web-first app for Zenoh observability and debugging. It connects to a Zenoh router through the Remote API WebSocket endpoint, subscribes to key expressions, streams live traffic, and helps you inspect payloads quickly. Desktop packages are still produced for Windows, macOS, and Linux.

The name "Carto" comes from "cartografo" (Spanish for mapmaker).

Table of Contents

• Features
• Screenshots
• Installation
• Zenoh Router Requirements
• Run Carto in Docker
• Zenoh Router Docker
• Development
• Load Testing
• Packaging
• Roadmap
• Keywords

Features

• Live Zenoh stream monitoring by key expression
• Multi-subscription workflow with pause, clear, and unsubscribe controls
• Stream filtering by key and message content
• Message drawer with decoded views for JSON, text, and binary payloads
• Protobuf schema loading and Protobuf decode support in stream view
• Publish messages with json, text, base64, and protobuf modes
• Recent key explorer and key-expression history for subscribe/publish flows
• Connection status, logs, and app-level diagnostics
• Settings import/export for sharing local profiles and schema setup
• Light and dark themes for long monitoring sessions

Screenshots

Dark mode stream view

Light mode stream view

Publish workflow

Installation

Prebuilt installers for Windows, macOS, and Linux are available on the Releases page.

Zenoh Router Requirements

Carto requires a Zenoh router with zenoh-plugin-remote-api enabled.

• Enable zenoh-plugin-remote-api on your router
• Ensure the Remote API WebSocket endpoint is reachable (default ws://127.0.0.1:10000/)
• REST is often exposed at http://127.0.0.1:8000/, but Carto uses WebSocket

Useful links:

• zenoh-plugin-remote-api downloads
• Adding plugins and backends to the Zenoh container

Run Carto in Docker

Pull the published image:

docker pull tabierto/carto:latest

Run it:

docker run --rm -p 8080:8080 tabierto/carto

Then open:

http://localhost:8080

If your Zenoh router is running on the same machine as Docker, you can use the normal local endpoint:

ws://127.0.0.1:10000/

Carto rewrites loopback addresses inside the container to the Docker host automatically. Direct non-loopback IPs also work as long as they are reachable from the container network.

Zenoh Router Docker

This repository includes a local Docker setup for Zenoh + Remote API:

cd docker
docker compose up --build

Default endpoint:

ws://localhost:10000

See docker/README.md for Docker-specific details.

Development

Requirements:

• Node.js 24+ for desktop builds
• Node.js for the default web server runtime
• Bun optional for experimentation

Run locally:

npm install
npm run dev:desktop

Run the web frontend locally:

npm run build:web
npm run dev:web

Run the web/server mode locally:

npm install
npm run build:server
npm run start:web

Experimental Bun server run:

bun install
npm run start:web:bun

Load Testing

Carto includes a local Zenoh load publisher for reproducing large-payload issues.

Default run:

npm run load:test -- --endpoint ws://127.0.0.1:10000/

That sends 100 messages to carto/load-test in bursts of 5, with payload sizes randomized between 600 KiB and 900 KiB.

Example heavier run:

npm run load:test -- --endpoint ws://127.0.0.1:10000/ --count 200 --burst 10 --pause-ms 50 --min-kib 600 --max-kib 900

Useful flags:

• --keyexpr to isolate the test stream
• --format json|text to switch payload shape
• --count to control total messages
• --burst and --pause-ms to shape the send rate

Packaging

Build all supported desktop targets locally:

npm run dist

Build per platform:

npm run dist:mac
npm run dist:win
npm run dist:linux

Desktop release automation remains in GitHub Actions via Electron/electron-builder while the app runtime moves toward a web-first architecture.

Keywords

Zenoh, Eclipse Zenoh, Zenoh inspector, Zenoh monitoring, Zenoh debugging tool, Zenoh desktop client, pub/sub observability, message stream viewer, key expression explorer, Electron Zenoh app, TypeScript desktop app

Made in Puerto Rico. 🇵🇷