Real-time coroutine execution trace viewer with hierarchical tree and mouse-centered Gantt chart, source-file/line links, SSE live streaming, theme toggle and clickable node details.
Comet Visualizer is a real-time web UI for visualizing Kotlin coroutine traces produced by Comet (Coroutine Telemetry). It presents structured concurrency as hierarchical tree views, concurrent Gantt charts, and execution metrics, making coroutine behavior easier to understand and analyze.
https://github.com/user-attachments/assets/900caecc-4b20-4dfb-ba57-ac44d622b9e3
See comet-demo for a full KMP sample app (Android + iOS) demonstrating Comet and comet-visualizer integration with real API calls and some coroutine patterns.
comet-visualizer/
├── shared/ # Kotlin Multiplatform data models
├── frontend/ # Kotlin/JS + Compose for Web UI
└── library/ # Server library (TraceServer + bundled frontend)
Add both dependencies to your project:
dependencies {
implementation("io.github.pandubaraja:comet:0.3.0")
implementation("io.github.pandubaraja:comet-visualizer:0.3.0")
}
import io.pandu.Comet
import io.pandu.comet.visualizer.TraceServer
io.pandu.core.telemetry.exporters.VisualizerJsonExporter
= runBlocking {
server = TraceServer(port = )
server.start()
comet = Comet.create {
exporter(VisualizerJsonExporter(server::sendEvent))
includeStackTrace()
}
comet.start()
launch(comet.traced()) {
launch(CoroutineName()) {
delay()
}
}
comet.shutdown()
server.stop()
}
Note: If running on an Android emulator or device, forward the port first:
adb forward tcp:8080 tcp:8080Then open
http://localhost:8080in your browser.
Copyright 2025
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
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