A Windows-first service that watches local directories for file changes and mirrors them to any rclone-supported backend — Google Drive, S3, Dropbox, OneDrive, SFTP, and 70+ others — with explicit include/exclude filtering.

Status: Released v1.0.0 (May 2026). Open source under MIT license.

Portfolio project. The point isn’t the file-sync service itself — it’s that it was built end-to-end by AI under direction, in six weeks, with zero lines of code written by me. The case study is the substance.

Key properties

  • On-write detection via Windows ReadDirectoryChangesW (no polling)
  • Selective filtering with per-project .syncignore files using .gitignore semantics
  • Bandwidth-efficient via MD5 checksum comparison and a deduplicating fair queue
  • Single binary with zero runtime dependencies (statically-linked SQLite)
  • Backend-agnostic through rclone — 70+ cloud and remote backends
  • Configurable delete policy: ignore, mirror, or quarantine
  • Background modes: Windows Service (admin) or per-user Scheduled Task (no admin)
  • Self-update flow with rclone auto-provisioning

Scale at v1.0.0

  • 282 git commits across 8 tagged releases (v0.4.0 → v1.0.0)
  • ~22,800 production Go lines + ~31,800 test Go lines
  • 1,060 Go test/fuzz functions
  • 216 BugTracker records (with 75 from independent cross-AI review)
  • ~10,700 lines of documentation
  • ISO-aligned engineering: Requirements (29148), Quality Model (25010), Quality Measurement (25023), Testing (29119)

Read more

I Shipped a Production Go Project Without Knowing Go — a case study on AI-assisted software development, written from the experience of building SelectiveMirror.