Kopia Backup Tool

Kopia is a fast and secure open-source backup tool with deduplication, compression, and encryption for local and cloud storage. Created by Jarek Kowalski, Kopia has over 8,700 stars as of 2026 and offers a modern alternative to traditional backup tools with a rich GUI, policy-based management, and broad cloud support. Key features include: cross-platform support (Windows, macOS, Linux, and NAS devices), content-defined chunking (CDC deduplication using rolling hash for optimal dedup across file modifications), compression (zstd, gzip, s2, and lz4), encryption (AES-256-GCM with per-repository keys, encrypted before leaving the client), incremental snapshots (O(1) creation time regardless of data size), cloud storage backends (Amazon S3, Google Cloud Storage, Azure Blob, Backblaze B2, Wasabi, MinIO, SFTP/SSH, WebDAV, and local filesystems), Kopia Repository Server (client-server architecture with shared deduplication across machines), policy engine (backup schedules, retention policies, compression, and inclusion/exclusion rules at global, per-user, per-host, and per-directory levels), KopiaUI (graphical interface via Electron for managing backups, browsing snapshots, and restoring files), snapshot scheduling (cron-like with configurable frequency and retention), parallel uploads (concurrent chunk uploads for faster backups), and file-level restore (browsing and restoring individual files without downloading the entire backup).