homebridge-cync-app

Homebridge plugin for integrating GE Cync devices with Apple HomeKit.

This plugin connects to your Cync account, discovers supported devices automatically, and exposes them to HomeKit through Homebridge. Where supported, communication is performed locally over LAN for improved responsiveness and reliability.

Features

• HomeKit support for GE Cync devices
• Automatic device discovery
• Support for lights, dimmers, switches, outlets, and light strips
  • Brightness support
  • Color temperature support
  • RGB color support where available
  • RGBIC Light Show support for compatible devices
  • RGBIC Music Show support for compatible devices
  • Optional HomeKit accessories for supported built-in shows
• Local LAN control for supported devices
  • Reduced cloud dependency
  • Faster state updates and command execution
• Child bridge compatible
• Homebridge UI configuration support
• Debug logging support for troubleshooting

Supported Devices

The plugin supports most common Cync lighting and power devices that are discovered through your Cync account, including:

• White bulbs
• Tunable white bulbs
• Full-color bulbs
• Dynamic RGBIC light strips
• Smart plugs and outlets
• Smart switches
• Smart dimmers
• Fan switches

New device types can often be supported quickly once identified.

If a device appears incorrectly in HomeKit or is missing functionality, please open an issue with:

• The device type
• A screenshot or product link from the Cync app
• Debug logs

Requirements

• Node.js 20 or newer
• Homebridge v1.8.0 or newer
• A GE Cync account
• At least one compatible Cync device available in the Cync app

Installation

Install through the Homebridge UI or manually with npm:

npm install -g homebridge-cync-app

After installation:

1. Open the Homebridge UI
2. Add and configure the plugin
3. Enter your Cync account email
4. Complete the login flow using the one-time verification code sent by Cync
5. Restart Homebridge

Devices should appear automatically after startup.

Tokens are cached locally to reduce repeated login prompts.

Shows by Device

After signing in, the plugin configuration dynamically lists every show-compatible Cync device. Expand a device to choose the built-in Light Shows, Music Shows, saved Custom Shows, and saved Segment scenes that should appear as HomeKit switches for that device.

Show selections are stored by Cync device ID, so renaming a device does not reset its configuration. Existing global show settings are migrated to per-device selections the next time the plugin configuration UI is opened and saved.

Device Notes

Color and Color Temperature

Some Cync devices expose both RGB color and color temperature controls. HomeKit may present these differently depending on the accessory category and Home app behavior.

Cync white presets are exposed to HomeKit as color temperature values, not as RGB colors. The Cync app presents presets such as Cool White, Daylight, Sunlight, Natural White, Early Morning, Sunrise, and Warm White as a discrete ladder. HomeKit represents the same idea as a continuous color-temperature slider using mired values, where lower mired values are cooler and higher mired values are warmer.

Because of that, the Home app may not visually match the Cync preset list one-for-one. For example, Natural White may appear near the center of HomeKit's temperature gradient, while Cool White and Warm White should appear near the cool and warm ends respectively. This is expected: HomeKit is showing the calibrated temperature position, while the Cync app is showing named presets.

The Home app's Swatch tab can look visually similar to Cync's white presets, but swatches are RGB color selections. Choosing a swatch may put the device into RGB color mode instead of tunable-white color-temperature mode. For best white-temperature behavior, use the Temperature control in HomeKit or the white preset list in the Cync app.

If a Cync white preset maps to an unexpected HomeKit position, enable debug logging and include the relevant compact state 0x43 or mesh state record lines when opening an issue. These lines include the Cync tone byte and the HomeKit mired value used by the plugin.

Outlets and Switches

Certain Cync device types are exposed as outlets instead of generic switches to improve HomeKit behavior and Siri integration.

LAN Communication

The plugin attempts to communicate with supported devices locally over the network for improved responsiveness compared to cloud-only control.

Troubleshooting

Device not responding

1. Confirm the device still responds in the official Cync app
2. Restart Homebridge
3. Enable debug logging
4. Check Homebridge logs for TCP or authentication errors
5. Power cycle the affected device if needed

Missing devices

If a device is not discovered:

1. Verify it appears in the Cync app
2. Restart Homebridge
3. Enable debug logging
4. Open an issue with:
   • Device type
   • Product screenshot or link
   • Relevant logs

Authentication Issues

If the Request Verification Code button appears unresponsive, verify that content blockers, privacy extensions, or similar browser protections are not blocking requests from the Homebridge UI.

Some users have reported that Safari's built-in content blocking features can prevent authentication actions from completing. If the button does not appear to do anything:

1. Temporarily disable content blockers for the Homebridge UI
2. Refresh the page
3. Request a new verification code again

If problems persist, try a different browser and review the browser developer console for errors.

Contributing

Issues and pull requests are welcome.

When reporting bugs, please include:

• Homebridge version
• Node.js version
• Device type(s)
• Relevant logs
• Steps to reproduce

Credits

This project builds on community research and prior work surrounding the GE Cync ecosystem.

Special thanks to:

• Homebridge
• nikshriv/cync_lights for extensive device support research and protocol implementation reference work
• Community members who provided device access, logs, testing, and protocol captures

Disclaimer

This project is not affiliated with or endorsed by GE Lighting or Savant.

HomeKit is a trademark of Apple Inc.