Got tired of every time I need to make an image section transparent — the website being a paywall, a watermark, or a "sign up to download." So I built a tiny self-hostable thing.
https://github.com/gabrielpires/make-it-transparent
What it does: pick up to 8 colors from an image (eyedropper or hex), each with its own tolerance, get a PNG back with those pixels alpha=0. That's the whole app.
Stack: Go, single static binary with the frontend embedded via `go:embed`. 17 MB distroless image, runs as nonroot, processes images in memory and throws them away.
Run it:
docker run --rm -p 8080:8080 ghcr.io/gabrielpires/make-it-transparent:latest
Or grab the `compose.yaml` from the repo if you want the hardened version (read-only FS, cap_drop ALL, no-new-privileges, tmpfs spool). Multi-arch (amd64 + arm64).
License: PolyForm Noncommercial — free for personal/hobby/research, NC clause is just so a SaaS can't lift it wholesale. Happy to answer questions.