restic is a fast, secure, and efficient backup program written in Go. It provides a command-line interface with subcommands for creating, restoring, managing, and verifying backups. The architecture is modular: a core repository layer handles encryption (AES-256-GCM), content-defined chunking for deduplication, compression (zstd), and pack-file storage. Multiple storage backends are supported via a common interface, including local filesystem, SFTP, S3, Azure Blob, Google Cloud Storage, Backblaze B2, OpenStack Swift, and rclone. The codebase is production-grade with extensive unit and integration tests, a FUSE mount for browsing snapshots, and a self-update mechanism. It is actively maintained with frequent releases and a large community.