Log Streaming

FlowDeck CLI can stream real-time app logs from your running apps, making it easy to monitor print, stderr, and OSLog output without switching to Console.app.

Streaming Logs

Run with Log Streaming

The easiest way to stream logs is to use the --log flag when running:

flowdeck run --workspace MyApp.xcworkspace --simulator "iPhone 16" --log

This builds, runs, and immediately starts streaming logs from your app. The same flow works for simulators, macOS apps, and physical devices launched by FlowDeck.

Stream Logs from Running App

If your app is already running, use the apps and logs commands:

# List running apps
flowdeck apps

# Stream logs from an app
flowdeck logs <app-id>

Example:

$ flowdeck apps
Running Apps:
  abc123  com.example.MyApp  iPhone 16 Pro
  def456  com.example.Test   iPad Pro

Use 'flowdeck logs <app-id>' to stream logs
Use 'flowdeck stop <app-id>' to stop an app

$ flowdeck logs abc123

Using OSLog in Your Code

FlowDeck captures logs from Apple’s unified logging system (OSLog):

import os

// Create a logger
let logger = Logger(subsystem: "com.example.myapp", category: "networking")

// Log at different levels
logger.debug("Debug: Starting request")
logger.info("Info: Request completed")
logger.warning("Warning: Slow response detected")
logger.error("Error: Request failed")

Log Levels

Level	Description
`debug`	Detailed debugging information
`info`	General informational messages
`warning`	Warning conditions
`error`	Error conditions
`fault`	Critical errors

Log Output

Logs are displayed with color-coded output based on log level when structured level metadata is available:

[DEBUG] 10:23:45.123 - Starting network request
[INFO]  10:23:45.234 - User logged in successfully
[WARN]  10:23:45.345 - API response slow (>2s)
[ERROR] 10:23:45.456 - Failed to parse JSON response

Stopping Log Streaming

Press Ctrl+C to stop streaming logs.

Stopping Running Apps

Stop an app that was launched by FlowDeck:

flowdeck stop <app-id>

Platform Notes

FlowDeck supports log streaming for:

iOS simulators
macOS apps
physical iOS devices launched by FlowDeck

On physical devices, FlowDeck follows the device console file created during launch. Message bodies are captured from launch onward, including OSLog debug/info/notice/error/fault calls, but OSLog severity metadata is flattened by the device console source.

Tips

Use specific subsystem and category names in your OSLog calls to make filtering easier:

let logger = Logger(subsystem: "com.example.myapp", category: "auth")

Debug-level logs may not appear in Release builds. Use Info level or higher for logs you always want to see.

Troubleshooting

No Logs Appearing

Ensure the app was launched by FlowDeck
Verify the app is still running on the selected simulator, device, or Mac
Check that the debug session started successfully

Too Many Logs

FlowDeck automatically filters to your app’s process. If you’re still seeing too many logs:

Use more specific subsystem/category names
Reduce debug-level logging in your code

Logs Not Updating

If logs stop appearing:

Check that the app is still running: flowdeck apps
Restart log streaming: flowdeck logs <app-id>

Overview

FlowDeck for AI

Interactive Mode (TUI)

Core Features

Command Reference

Advanced

Support

Streaming Logs

Run with Log Streaming

Stream Logs from Running App

Using OSLog in Your Code

Log Levels

Log Output

Stopping Log Streaming

Stopping Running Apps

Platform Notes

Tips

Troubleshooting

No Logs Appearing

Too Many Logs

Logs Not Updating

​Streaming Logs

​Run with Log Streaming

​Stream Logs from Running App

​Using OSLog in Your Code

​Log Levels

​Log Output

​Stopping Log Streaming

​Stopping Running Apps

​Platform Notes

​Tips

​Troubleshooting

​No Logs Appearing

​Too Many Logs

​Logs Not Updating

Streaming Logs

Run with Log Streaming

Stream Logs from Running App

Using OSLog in Your Code

Log Levels

Log Output

Stopping Log Streaming

Stopping Running Apps

Platform Notes

Tips

Troubleshooting

No Logs Appearing

Too Many Logs

Logs Not Updating