dropzone

A lightweight, cross-platform desktop app (GUI + system tray) that watches for new screenshots and screen recordings, compresses them, and uploads them to your Cloudflare R2 bucket automatically. After each upload a clean public URL is copied to your clipboard (ShareX-style).

• Screenshots → compressed to lossless WebP → uploaded.
• Recordings → original uploaded first (fast availability) → re-encoded with ffmpeg (H.265 by default) → the R2 object is replaced with the smaller version.
• Watches your OS capture folders and the clipboard (so Win+Shift+S works).
• Local files are never modified.

Requirements

• Go 1.24+ and a C compiler to build (Fyne uses cgo + OpenGL). On Windows: WinLibs / MSYS2 / TDM-GCC. CGO_ENABLED=1.
• ffmpeg on your PATH for video compression (screenshots work without it). If ffmpeg is missing, recordings are still uploaded — just not compressed.

Build

# from the repo root
go mod tidy
CGO_ENABLED=1 go build -o dropzone ./cmd/dropzone
# Windows (console-less GUI build — no terminal window):
#   go build -ldflags "-H=windowsgui" -o dropzone.exe ./cmd/dropzone

Configure

Just launch dropzone — the window opens on the Settings tab. Enter your R2 details and click Save & Apply (hit Test connection first to check them). Watching starts immediately.

Prefer a terminal? ./dropzone --setup does the same interactively, and ./dropzone --verify checks your saved credentials.

It stores non-secret settings in a JSON config and your secret access key in the OS keychain (Windows Credential Manager / macOS Keychain / Linux Secret Service). Config location:

OS	Path
Windows	%AppData%\dropzone\config.json
macOS	~/Library/Application Support/dropzone/config.json
Linux	~/.config/dropzone/config.json

You'll be asked for:

• Account ID — your Cloudflare account ID.
• Access Key ID / Secret Access Key — an R2 API token, ideally scoped to just this one bucket (least privilege).
• Bucket name.
• Public base URL — your bucket's custom domain (e.g. https://cdn.example.com), used to build the shareable links.

Verify credentials any time with ./dropzone --verify.

See config.example.json for all options.

Config options

Key	Meaning
watchFolders	Explicit folders to watch. Empty = auto-detect OS defaults.
watchClipboard	Also upload images copied to the clipboard.
copyLinkToClipboard	Copy the public URL to the clipboard after upload.
keyPrefix	Optional root prefix for all object keys.
image.format	webp-lossless (default) or jpeg.
image.jpegQualityFallback	JPEG quality if WebP fails / format=jpeg.
video.codec	h265 (default), h264, or av1.
video.crf	Quality (lower = better). 0 = codec default (h265 28 / h264 23 / av1 30).
video.preset	ffmpeg preset (medium default; ignored for av1).
video.ffmpegPath	Explicit ffmpeg path (else looked up on PATH).

Run

Launch dropzone (double-click the binary). You get:

• A dashboard window with two tabs:
  • Status — live activity, a Pause/Resume button, and a list of recent uploads (click one to copy its link).
  • Settings — edit R2 credentials, watch folders, video codec, and the clipboard/link options; Save & Apply restarts watching immediately.
• A system-tray icon (menu: Open dropzone · Pause/Resume · Start at login). Closing the window hides to tray — the app keeps watching in the background.

Object layout in R2

[keyPrefix/]images/2026/07/03/<ulid>.webp
[keyPrefix/]video/2026/07/03/<ulid>.mp4

Keys are date-organized and use a time-sortable ULID to avoid collisions.

Notes / limitations

• Detection is folder + clipboard based. Default capture folders are auto-detected per OS but are user-relocatable; set watchFolders if yours differ (especially on Linux, where it varies by desktop).
• Pause drops captures taken while paused (local files are kept, so nothing is lost — they just aren't uploaded).
• Linux tray needs a StatusNotifierItem/AppIndicator host (GNOME needs the AppIndicator extension).