Introducing Syncronote
Turn Any Audience Into a Synchronized Display
Every screen becomes one piece of something bigger. A stadium wave, a concert collage, a classroom message — all in perfect sync, on phones and browsers alike.
Part of Cronote — 1M+ reminders delivered across 50+ industries
How It Works
Three Steps to Synchronized Magic
No special hardware. No app download for your audience. Just a browser.
Create
Choose your Syncronote type, enter your message, and customize the display to match your event.
Connect
Share a join link or QR code with your audience. Each person opens it on their phone or computer.
Sync
Hit go. Every screen lights up simultaneously, each showing its piece of the display in perfect real-time sync.
Syncronote Types
Two Ways to Synchronize
More types coming soon. These two ship at launch.
Static Banner
Splits your message across every connected device. Each screen shows its portion — line them up side by side to reveal the full message.
Scrolling Banner
A synchronized scrolling message that flows across every screen with phase-offset timing. Each device shows a different segment of the scroll, creating a seamless wave effect.
Use Cases
Where Syncronote Shines
Anywhere you have an audience, you have a display.
Classroom
Every student's device plays the same song or displays the same lesson simultaneously.
Concert
Audience members each show one piece of a collage, turning the crowd into a giant mosaic.
Church
Display scripture, lyrics, or announcements synchronized across the entire congregation.
Wedding
Create a synchronized light show or display a message from the couple across all guest devices.
Stadium
Coordinate a wave effect or spell out your team name across the stands.
Conference
Engage attendees with synchronized interactive displays during keynotes and breakout sessions.
The Technology
Real-Time. Millisecond-Precise.
Syncronote uses WebSocket connections and Redis pub/sub to synchronize every connected device with millisecond precision. No polling, no delays — just instant, simultaneous updates across every screen.
Built on the same infrastructure that delivers over a million reminders, hardened for real-time performance at scale.
Under the Hood
How Syncronote Keeps Devices in Lock-Step
A timing-object architecture that synchronizes motion state across every connected device with sub-100ms precision.
Server Layer
Timing Layer
Client Layer
Timing Object & State Vectors
Syncronote's core abstraction is a timing object — a shared clock that represents linear motion through a state vector of position, velocity, acceleration, and timestamp. Every connected device derives its display state from the same authoritative vector, so a scrolling banner's offset or a static banner's segment assignment is always consistent across all phones.
Clock Skew Correction
No two devices keep perfectly identical clocks. When a client connects, the server runs a skew-estimation handshake to calculate the offset between the client's local clock and the server's reference clock. All incoming state vectors are translated through this offset, so a timestamp from the server maps to the correct local instant — even on devices whose clocks are seconds apart.
WebSocket + Redis Pub/Sub
Each client holds an open WebSocket to the Syncronote server. When the organizer triggers "go," the server publishes the new state vector to a Redis pub/sub channel. Every server instance subscribed to that channel immediately pushes the update to its connected clients — no polling, no HTTP round-trips. This fan-out architecture means adding more server instances increases capacity without adding latency.
Client-Side Extrapolation
Between server updates, each device independently extrapolates its position using the state vector's velocity and acceleration. Because every client starts from the same vector and applies the same formula — p(t) = p0 + v⋅t + ½a⋅t² — all devices stay in sync without requiring a constant stream of updates. This minimizes bandwidth and keeps the experience smooth even on slower connections.
Syncronote's timing-object model draws on the concepts described in the W3C Timing Object draft specification (Web Timing Community Group, December 2024). The spec defines a platform-level abstraction for synchronizing media and timed content across devices using shared state vectors, clock-skew estimation, and an external timing provider model — the same principles that power Syncronote's real-time synchronization layer.
Be the First to Try Syncronote
We'll notify you as soon as Syncronote is ready to use.
Part of Cronote. Free plan available.