Patcher

A patch is a thought you can lose by pulling one cable

A modular synthesizer holds its music in the cables. The patch — the exact state of every connection and knob — is the composition. And it is completely ephemeral: repatch for the next idea, and the last one is gone unless you wrote it down.

For years, "writing it down" meant photographing the rack and burying the photos in a spreadsheet. The Eurorack community was scattered across forums, Reddit, and Discord, with no shared home for the things that actually matter day to day: what your patches were, how other people used the same modules, and a canonical record of the hardware itself. Existing tools were either single-vendor silos or generic note apps that understood nothing about signal flow.

Patcher started as my answer to that frustration and grew into something bigger: a digital twin of your modular system. Not a sketchpad, not a wishlist — a living, structured record of the racks, modules, and patches you actually have, kept in sync with the physical thing in your studio.

One workspace for the whole modular workflow

Everything in Patcher hangs off a community-maintained module database with accurate specs — dimensions, power draw, panels. On top of that sit the tools musicians reach for daily:

• Patch documentation

  Describe signal routing connection by connection, with live stats for cables, modules, and multiples. Instance-aware patching handles repeated modules, and app-wide auto-save means an idea is never lost to a missed click.

• Rack planning

  Drag-and-drop placement with live HP, power, and balance analysis — so you find out a rack won't work before you've bought the case, not after.

• Module tracking

  Your collection as structured data: what you own, what's racked, what's on the shelf. Multi-panel modules, alternate firmware, the lot.

• Community discovery

  Public profiles, contributor stats, and browsing by module, tag, or musician. See how someone else patches the same oscillator you own — that's where new music comes from.

Free, open, and built with its community

Patcher is free and open source under AGPL-3.0, with no ads, no paywalls, and no account required to browse public content. That isn't a growth tactic — it's the design. A hardware database is only as good as the people maintaining it, and people contribute to commons, not to catalogs they don't own. The database grows because anyone can add to it, and a public open API means the data stays useful beyond the app itself.

The first version launched with zero users and broke in three browsers. Shipping it anyway was the right call: feedback from the Bologna Modulare community shaped every feature since. A tool for one person is a script. A tool for a community is a product — and the community has been Patcher's co-designer for years now.

Five years in, one coherent product

What began in 2021 as a way to stop photographing a rack is now at v6.5: a server-rendered Angular application on Supabase and PostgreSQL, with end-to-end test coverage, moderation tooling, manufacturer pages, public profiles, and an onboarding flow that takes a new musician from empty account to documented system in minutes. The releases stopped being about single headline features a while ago — the work now is making the whole thing feel like one instrument.

The rack in the corner of my studio has a twin that never forgets a patch. That was the whole point — and now it holds thousands of other people's systems too.