Signal is a full-featured, open-source online MIDI editor built into your browser—no installation needed. It offers multi-track piano-roll editing with velocity, pitch bend, modulation, tempo automation, and support for non‑4/4 time signatures. You can load custom SoundFonts, record MIDI input, export WAV, and run it as an installable PWA or desktop app

Stuart Memo’s Sympathetic Synthesizer System Mk 1 is an analog-style Web‑Audio synth you can use directly in your browser. It offers three oscillators (triangle, sawtooth, square), LFO, noise generator, filters with ADSR envelopes, and MIDI support—perfect for deep sound design and hands-on exploration

WebSynths Grooves is a spectacular free browser-based drum machine and sample library. Featuring an 8-track polymetric sequencer, randomization, MIDI support, and hundreds of play-ready drum one-shots, you can design grooves, save WAV exports, or download sample packs. A must-have tool for beat-makers and browser‑music lovers.