REAPER Control — Stream Deck Plugin

A Stream Deck plugin that runs REAPER actions directly over REAPER's built-in web interface — no hotkey assignment, no keystroke emulation, no REAPER-side extension or ReaScript required.

The problem it solves: today, triggering a REAPER action from a Stream Deck means assigning a hotkey to that action in REAPER, then configuring a Stream Deck key to send that keystroke. That burns a finite keyboard namespace, breaks when focus is elsewhere, collides with other apps' shortcuts, and can't reach the thousands of actions that have no hotkey. This plugin replaces that with a direct path: pick an action, press a key, REAPER runs it.

Status

Actively in development, milestone by milestone. Not yet packaged for the Marketplace.

Milestone	Status
1. Protocol verification	✅ Done — see docs/protocol-findings.md
2. Skeleton, transport layer, Run Action key	✅ Done
3. Transport & Track Control keys, state manager, polling	✅ Done
4. Action database, fuzzy search, browser UI	✅ Done
5. Action import (user's exported action list)	✅ Done
6. Dials (Stream Deck+)	Skipped for now (no Stream Deck+ to test against)
7. Polish (icon art, error states, diagnostics, localization scaffolding)	✅ Done
8. Release (Marketplace assets, submission)	Not started

What works today

• Run Action — trigger any REAPER action by numeric or named command ID (40044, _SWS_ABOUT, ReaPack script IDs, …), with a searchable action browser (fuzzy search, favorites, recents) instead of hand-typing IDs. Import your own action list (via the SWS action SWS/S&M: Dump action list (all actions)) to make SWS and ReaPack scripts searchable too.
• Transport — play, stop, pause, record, repeat, go to start/end, with live lit/dim feedback driven by REAPER's actual transport state.
• Track Control — mute, solo, record-arm, select, targeting a track by number, the current selection, or master, with live two-state feedback.
• A setup panel that walks through enabling REAPER's web interface, plus a Test Connection button with specific, actionable diagnostics. It re-expands automatically if a previously-working connection drops, and every key shows a small disconnected badge without losing its normal icon.
• A Copy diagnostics button (plugin/OS/Stream Deck versions, redacted connection settings, last 20 log lines) for support requests, and inline PI warnings for an unrecognized action ID or an out-of-range track number.

Requirements

• REAPER 7.x with the built-in web browser interface enabled (Options → Preferences → Control/OSC/web → Add → Web browser interface) — the plugin's setup panel walks through this.
• Stream Deck app 6.5+, macOS 12+ or Windows 10+.

Documentation

• reaper-streamdeck-spec.md — the full implementation spec.
• docs/protocol-findings.md — REAPER web interface behavior verified live against a real instance. This is the source of truth for anything protocol-related, not the spec's own assumptions where the two disagree.
• CLAUDE.md — conventions and gotchas for working on this codebase.
• docs/marketplace-listing.md — draft copy for the Elgato Marketplace submission (tagline, description, privacy statement, release notes).

Development

Requires Node 20.

npm install
npm test           # vitest
npm run typecheck   # tsc --noEmit across the Node, test, and PI (browser) projects
npm run build        # rollup -> com.schapps.reaper.sdPlugin/{bin,ui/js}
npm run build:actions # regenerate data/actions-native.json from tools/ActionList.txt
npm run build:icons   # rasterize design/icons/*.svg -> the PNGs the manifest requires

To try it locally in a running Stream Deck app:

npx @elgato/cli link com.schapps.reaper.sdPlugin
npx @elgato/cli restart com.schapps.reaper

npm run watch rebuilds and restarts the plugin automatically on save.