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Duplicacy is a new generation cross-platform cloud backup tool based on the idea of Lock-Free Deduplication.


This repository hosts source code, design documents, and binary releases of the command line version of Duplicacy. There is also a Duplicacy GUI frontend built for Windows and Mac OS X available from https://duplicacy.com.

There is a special edition of Duplicacy developed for VMware vSphere (ESXi) named Vertical Backup that can back up virtual machine files on ESXi to local drives, network or cloud storages.


There are 3 core advantages of Duplicacy over any other open-source or commercial backup tools:

  • Duplicacy is the only cloud backup tool that allows multiple computers to back up to the same cloud storage, taking advantage of cross-computer deduplication whenever possible, without direct communication among them. This feature literally turns any cloud storage server supporting only a basic set of file operations into a sophisticated deduplication-aware server.

  • Unlike other chunk-based backup tools where chunks are grouped into pack files and a chunk database is used to track which chunks are stored inside each pack file, Duplicacy takes a database-less approach where every chunk is saved independently using its hash as the file name to facilitate quick lookups. The lack of a centralized chunk database not only makes the implementation less error-prone, but also produces a highly maintainable piece of software with plenty of room for development of new features and usability enhancements.

  • Duplicacy is fast. While the performance wasn’t the top-priority design goal, Duplicacy has been shown to outperform other backup tools by a considerable margin, as indicated by the following results obtained from a benchmarking experiment backing up the Linux code base using Duplicacy and 3 other open-source backup tools.

Comparison of Duplicacy, restic, Attic, duplicity

Getting Started


Duplicacy currently provides the following storage backends:

  • Local disk
  • SFTP
  • Dropbox
  • Amazon S3
  • Wasabi
  • DigitalOcean Spaces
  • Google Cloud Storage
  • Microsoft Azure
  • Backblaze B2
  • Google Drive
  • Microsoft OneDrive
  • Hubic
  • OpenStack Swift
  • WebDAV (under beta testing)
  • pcloud (via WebDAV)
  • Box.com (via WebDAV)

Please consult the wiki page on how to set up Duplicacy to work with each cloud storage.

For reference, the following chart shows the running times (in seconds) of backing up the Linux code base to each of those supported storages:

Comparison of Cloud Storages

For complete benchmark results please visit https://github.com/gilbertchen/cloud-storage-comparison.


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