Copyparty – Turn almost any device into a file server

Feature Set & Architecture

• Written in Python as a single, no-dependency file (with a few bundled “stolen” libs and lots of hand-rolled utilities like multipart parsing, chunked reads, atomic moves, etc.).
• Users are impressed by the breadth of features: resumable uploads/downloads (including the “upload half → start download → finish upload” trick), RSS feeds, media playback (including chiptunes), search/browsing, and general “does almost everything” behavior.
• Philosophy is explicitly “inverse Linux”: one tool that does many things “okay,” not a minimal, composable core.

Use Cases & Deployment

• Popular real-world uses: LAN parties, home media server, music player for old tablets, ebooks/music library sharing, clipboard sync across devices, quick file sharing between phones and PCs.
• Strong interest in running it on old Android phones via Termux as a low-power shelf server; the project itself was “born in Termux.”
• Demo server is praised as extremely fast, even under HN load.

UX, Demo & Vibes

• The README and demo video are repeatedly described as fun, humorous, and surprisingly compelling; several people went from “just another file browser” to “what the heck” as more features appeared.
• Nostalgic reactions to resumable transfers, evoking dial‑up days, BBS protocols, and old download managers.

Security, Code Quality & Scope Limits

• Some commenters want “no bugs, tight defaults, minimal attack surface” and say this is not that product.
• Concerns: dense, short variable names and idiosyncratic style make auditing hard; a recent XSS fix is cited. The README itself warns against using the code to learn Python.
• Others argue that zero external deps at least localizes bugs and praise it as “good software,” but not necessarily ideal for high-security scenarios.
• Explicit limitation: no full bidirectional sync like Nextcloud/Syncthing; only one‑way sync.

Ecosystem, Comparisons & Legal Concerns

• Compared and contrasted with torrents (most agree it is not “just torrent reinvented”), FTP/SFTP/rsync, Nextcloud, Syncthing, Caddy, and many ad‑hoc file‑sharing tools.
• Some debate around licenses of alternatives (AGPL described in the docs as “problematic,” which others dispute).
• Discussion of running it in trickier environments (behind CGNAT, via relays/VPNs) and worries about liability for user-contributed illegal content on local “digital libraries.”