convt: Local File Conversion With a Right-Click

Searching the web for a file converter means handing your file to someone else’s server first — contracts, ID scans, unpublished footage all make the trip. convt (written in Rust, open source under AGPL-3.0, created October 6, 2026, 290 stars in four days) pulls the job back to your machine: right-click a file, pick a format, and the result lands next to the original. Nothing is uploaded. The engines are native pieces your machine already has — FFmpeg for audio and video, PDFium for PDFs, LibreOffice for Office — and convt acts as the router: across 40 formats (14 image, 5 video, 7 audio, 14 document, per the formats page generated from the converter itself), when no engine converts directly it plans a route of at most three hops, reaching combinations like HEIC to DOCX that no converter menu would ever put side by side.

Core features

• 40 formats across five native engines: FFmpeg (MP4/MOV/WebM/MKV/MP3/FLAC and more), LibreOffice (Word/Excel/PowerPoint and their open formats, plus save-as-PDF), PDFium (PDF pages rendered to PNG/JPEG), image and resvg (photos and SVG, including AVIF/OpenEXR/QOI), libheif or macOS sips for HEIC.
• Multi-hop routing: when no engine can convert directly, convt plans a chain of at most three steps, so the menu shows every reachable target rather than only direct pairs.
• Right-click integration: a Finder menu on macOS and file manager menus on Linux ship with the package; the Windows Explorer menu is built (crates/convt-shell) but not yet in the release installer.
• A CLI in the same install, friendly to agents: convt clip.mov --to mp4, a whole directory with convt photos/ --to webp -r, convt lease.pdf --to png --pages 1-3; convt --skill prints a SKILL.md for coding agents to read.
• An optional document pack: Word/Excel/PowerPoint support installs on request; released Windows builds fetch a pinned pack from a GitHub release and verify its SHA-256 — the engines never start that download themselves.
• A paid cloud API: the same engines run in sandboxed worker processes server-side, with a TypeScript SDK for teams that need batch conversion off their own hardware.
• Look before you convert: convt engines lists what this machine can run, convt targets photo.heic shows every format one file can reach, and convt formats / convt presets dump the global tables.

Typical use cases

• Privacy-sensitive conversions: contracts, scanned IDs and unreleased footage change format without leaving the disk.
• Batch media cleanup: a folder of HEIC to JPG, a pile of MOV to MP4 — one right-click or one command.
• Giving agents conversion powers: the SKILL.md from convt --skill lets a coding agent look up formats, pick targets and run conversions on its own.

Quick start

On macOS (Apple silicon), via Homebrew:

brew tap opencoredev/convt https://github.com/opencoredev/convt
brew install --cask convt

The signed app and the convt CLI both land on your machine. Check which engines are available and what a file can reach:

convt engines
convt targets photo.heic
convt clip.mov --to mp4

Mind the licensing: packaged builds start a 7-day trial on the first conversion; building from source is unrestricted. A Windows MSI and Linux .deb/.rpm/AppImage are on convt.app/download.

Summary

For conversion where the file never leaves the machine, convt is one of the most complete options available: one app covering images, audio and video, PDFs and Office, with the CLI and agent interface thrown in. AGPL-3.0, built in Rust with GPUI (Zed’s UI framework), maintained by the OpenCore organization; the signed desktop builds and the cloud API are paid, and “convt” plus its logo are trademarks outside the code license. Three caveats: Office conversion needs LibreOffice on your PATH; the Windows right-click menu is not in the installer yet; and the project is four days old with 290 stars (checked 2026-10-10), so run convt engines to see what your own machine actually routes.

On the same “files never touch someone else’s server” path, croc and Syncthing cover transfer and sync; convt fills in the missing piece: the format itself.