Release of 'DeviceTick': An OSS Timer for Real-Time Synchronization Across Multiple Devices

NITI Technology Inc. (Headquarters: Hongo, Bunkyo-ku, Tokyo; CEO: Tomoya Kaneko) has released 'DeviceTick', an open-source software capable of real-time synchronization of countdown and Pomodoro timers across multiple devices, on GitHub. It is available under the MIT license.

The DeviceTick experience simultaneously fulfills the following four criteria. In the realm of OSS timers, implementations satisfying this combination are currently very limited.

Live Synchronization — Aligns the 'timer state currently running at this very moment' across all devices, rather than just historical data.

No Login Required & Instant Joining via URL — Zero account registration; sharing is done with a single link.

Included Public Protocol — API contracts are published using JSON Schema, enabling third parties to build custom clients such as CLI, desktop apps, or physical timer integrations.

Extremely Lightweight Self-Hosting — A single Go binary, no database required, executable with a simple 'docker compose up' command.

Repository: https://github.com/NITI-Lab/DeviceTick

■ Background: The Problem Existing OSS Timers 'Haven't Solved'

With the spread of remote and hybrid work, it has become commonplace for users to switch between PCs, smartphones, and tablets while working. However, timers almost always run separately on each device.

For example, 'stopping a focus timer started on a PC from a smartphone after leaving the desk' or 'checking the remaining time of a timer running on a PC from a smartphone'—these simple operations cannot be achieved with most timer apps. This is because the timer only runs within the device it was started on and cannot be viewed or controlled from other devices.

While there are many open-source timer apps, most fall short in one way or another, leaving limited options for a lightweight, open solution that provides the simple experience of 'aligning the currently running timer' across multiple devices.

DeviceTick is a set consisting of a timer synchronization engine designed to fill this gap and its thin web client.

■ The Uniqueness of DeviceTick

1. A Mechanism to Prevent Clock Drift Between Devices

The server centrally manages 'how many seconds have passed' for the timer and distributes this information to all devices. Even if the clocks on individual devices are slightly out of sync or if a device wakes up from sleep, the remaining time displayed on the screens will align. The switching between focus and break periods in Pomodoro is also determined by the server and communicated to all devices, preventing situations where only one device fails to switch.

2. Joining Completed with a Single Link

When a room is created, a short ID is issued, and simply passing that URL allows other devices or participants to join the same session. Account registration, email verification, and app installation are all completely unnecessary. Whether pasting the URL into a chat, sharing instantly via QR code, or distributing to a group of students from an instructor, onboarding for sharing is zero.

3. Countdown and Pomodoro in a Single App

Users can utilize a simple countdown (any number of minutes) and a Pomodoro timer (focus -> break cycle, multiple sets) within the same app, with the same user experience. There is no need to switch apps to use different modes.

4. Open Specifications Enabling Third-Party Integrations

DeviceTick provides its API specifications (request/response formats, event delivery formats) as public documentation. This allows third parties to develop custom CLI tools, desktop apps, integrations with physical timers using Raspberry Pi, or embed it into internal company tools without needing to read the source code of DeviceTick itself. The design intends to 'promote this synchronization model as a common foundation' even more than 'promoting the implementation of DeviceTick'.

5. Ultra-Lightweight Design for Self-Hosting

Neither database construction nor complex setups are required; a single command starts both the web interface and the API server. It can be operated on personal VPS, internal company servers, or hardware in the class of a Raspberry Pi. There is no need to 'increase reliance on cloud services just to share a timer.'

■ Examples of Use Cases

Personal Multi-Device Usage — Checking and operating the remaining time on a smartphone at hand while working on a PC at a desk.

Focus Block Sharing for Remote Teams — Sharing the same 25-minute Pomodoro with team members in different locations.