Introduction
ByteSync is an open-source application designed to synchronize data efficiently between one or several computers. The app transfers only the differences (block-level deltas) and protects every exchange with end-to-end encryption (E2EE). It can be used locally on a single machine or remotely between multiple machines — and even both at the same time within a single session.
Older versions of the documentation referred to “Local Synchronization” and “Cloud Synchronization” as separate modes. This is no longer the case. ByteSync now uses a single, unified model based on Synchronization Sessions.
Open-Source and Free
ByteSync is fully open-source and currently free to use. The source code is available on GitHub, ensuring transparency and auditability. This means the community can review how data is handled, propose improvements, and contribute directly to the project.
This commitment to openness also makes ByteSync a valuable educational resource. IT administrators and developers can explore real-world implementations of synchronization sessions, delta-based data transfer, and secure communication.
Core Idea: the Synchronization Session
All operations happen inside a Synchronization Session, which is the workspace where participants collaborate to compare and synchronize data. A session may involve a single member (local-only) or multiple members (remote or mixed). Within a session, each participant contributes data through Data Nodes, which contain one or more Data Sources (directories or files).
To get familiar with these objects, see: Session Members, Data Nodes & Data Sources and Synchronization Sessions – Overview.
How it Works (at a Glance)
The synchronization workflow follows four simple steps:
- Create or Join a Session – The first member starts the session, other members join with a Session ID and Password. See Creating or Joining a Synchronization Session.
- Prepare Members & Nodes – Each member adds Data Nodes and their Data Sources (folders or files). See Members, Data Nodes & Data Sources.
- Inventory & Comparison – ByteSync inventories the data (listings and deltas) and compares results across nodes. See Data Inventory and Data Comparison.
- Actions & Synchronization – You decide what to do (copy, update, delete, ignore) and run the sync. See Synchronization Actions and Data Synchronization.
What Makes ByteSync Different
Efficient by design. ByteSync computes signatures and transfers only the differences required to align the target with the source. This reduces both time and bandwidth, especially on large files. See Delta Synchronization for details.
Simple and flexible. No VPN or firewall configuration is required to collaborate with remote machines. A single session can mix local and remote Data Nodes; you decide the topology that fits your workflow.
Secure. All exchanges between members are protected with end-to-end encryption (E2EE). Devices must be approved via the Trusted Clients mechanism before they can participate.
For a detailed overview of how ByteSync protects your data and maintains a zero‑knowledge architecture, see the Security & Privacy.
Cross-platform. ByteSync runs on Windows, macOS, and Linux. See Requirements for details.
About the Publisher
ByteSync is maintained by POW Software, an independent publisher committed to building secure and practical tools for data management. The project is continuously evolving, with feedback from both the open-source community and early adopters shaping new features.
If you want to contribute, follow the project on GitHub or join the community discussions to share feedback, report issues, or suggest improvements.
