drumha.us
Drumhaus is a browser-based drum machine and beat sequencer with 8 voices and 16 steps. It supports chainable patterns with per-step velocity, flam, ratchet and accent, per-voice filters, pitch and decay, and a master effects bus with reverb, compressor, phaser and saturation. Beats can be exported to WAV and presets shared via link. It is free and requires no account.