AssetSync is a Ruby gem that synchronizes compiled assets from a Rails (or Rack) application to cloud storage providers such as AWS S3, Rackspace Cloud Files, Google Cloud Storage, Azure Blob, and Backblaze B2. It hooks into the Rails asset pipeline by enhancing the `assets:precompile` Rake task, automatically uploading assets after compilation. The gem supports incremental uploads (uploading only new or changed files), optional deletion of obsolete remote files, gzip/brotli compression, concurrent uploads, CDN invalidation, and caching of remote file lists for performance. Configuration is flexible via Rails initializer, YAML file, or environment variables. The codebase is well-structured with a clear separation of concerns (`Config`, `Storage`, `MultiMime`), comprehensive unit and integration tests, and support for multiple Rails versions (6.1 through 8.1) and Ruby versions (3.0+). It is actively maintained with recent releases and zero Dependabot alerts.