Pure Data (Pd)
Miller Puckette’s “free real-time computer music system”, copyright 1997–2024 with contributors, on Linux, macOS and Windows. You program it by connecting graphical objects: boxes on a canvas, cables between them, data and audio flowing along the wires. Real-time audio and MIDI, extended by community-written externals — video, 3D graphics, specialized DSP — reachable from the Help menu. 2.1k stars, 7,866 commits, still moving. Custom licence in LICENSE.txt, with separate copyrights for bundled components like Tcl/Tk.
T1 — the project’s own repository. Thin on specifics: no version number and no release cadence on the page, so “actively developed” rests on the commit count.
The patch is the program
This wiki keeps returning to modular-routing — signal paths built from small units and cables, in Eurorack, in vcv-rack, in reason‘s virtual rack. Pd is that idea as a programming environment: the cable is not a metaphor for a patch cord, it is the control and data flow of the program. Nothing here is closer to VCV Rack in form and further from it in intent — one is a modular synth simulated on screen, the other is a general dataflow language that happens to be very good at audio.
Set it beside csound, which arrived the same day. Csound writes the instrument as text and the performance as a score; Pd draws the instrument and lets you play it live. Both descend from the same computer-music lineage at Bell Labs and MIT, and between them they cover the two ways a synthesizer can be written down. Puckette also wrote Max, the commercial patching environment behind Max for Live — the toolchain under beast-repeat in this wiki — so the graphical-patching idea reaches ordinary production software through him, though this repository page does not say so.
Extensibility as the deployment story
Externals matter more here than a feature list suggests. A community that can add DSP objects in C means the environment grows without the maintainer, which is why a 1997 program still covers video and 3D. The comparison in this spoke is vcv-rack‘s third-party module ecosystem: same shape, and it is the only reliable way a patching environment stays current.
Related
vcv-rack · csound · modular-routing · reason · beast-repeat · daw · synthesis