Free browser synth
Online Synthesizer
Play a free online synthesizer (online synth) right in your browser. This virtual synthesizer builds every sound from two oscillators, noise, a resonant low-pass filter, two envelopes and an LFO. Play synth online with your computer keyboard, mouse, touchscreen or a MIDI controller. Using a synthesizer online takes no download and no sign-up.
- 6presets
- Computer keyboard or MIDI
- Free, no signup
Play the Synthesizer Online
Tap a note or type on your computer keyboard to start. Pick a preset above; Rack opens the controls.
Tap a key or type a letter to play
Computer keys on
Synthesizer Simulator
A synthesizer simulator should let you shape a sound, not only choose one.
Two oscillators into a resonant filter
Each note mixes two oscillators (sine, triangle, sawtooth or square) and white noise through a resonant 12 dB-per-octave low-pass filter. Detune or shift the second oscillator for a wider sound.
Play the synth-
Six presets
Start from Analog-style, Pad, 8-bit square, Bass, Pluck or Lead, then change any control.
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Filter and amp envelopes
One envelope shapes the volume of each note; the other sweeps the filter cutoff up and back.
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LFO on pitch, filter or volume
A sine, triangle or square LFO adds vibrato, a filter sweep or tremolo.
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Poly or mono with glide
Play chords of up to 16 notes, or mono legato with adjustable glide.
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Delay
An echo with time, feedback and mix, generated without loading a sound file.
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Recording
Record a take and play it back at once with the synth's current sound.
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MIDI controller input
Play from a USB MIDI controller in browsers with Web MIDI, such as Chrome or Edge.
Play the Synthesizer on Your Computer Keyboard
Computer keyboard to note map
Letters and numbers play natural notes; hold Shift for the sharp above. The octave buttons move the 61-note window between C1–C6 and C2–C7.
- C2 – B2
- 1 2 3 4 5 6 7 · ! @ $ % ^
- C3 – B3
- 8 9 0 q w e r · * ( Q W E
- C4 – B4
- t y u i o p a · T Y I O P
- C5 – B5
- s d f g h j k · S D G H J
- C6 – B6
- l z x c v b n · L Z C V B
- C7
- m
How to Play the Synthesizer
Three steps from the first note to a sound of your own.
- Pick a preset. Choose one of the six presets and hold a note to hear how the sound starts and fades.
- Move the cutoff. Open the rack and turn the filter cutoff and resonance while a note sounds.
- Shape the envelopes. Lengthen the attack for a slow swell, or shorten decay and sustain for a pluck, then add the LFO or the delay.
Synthesizer Sounds and Voices
Six starting presets, and how this digital synthesizer makes sound.
Analog-style
Two slightly detuned saws through a resonant filter with a quick envelope sweep. The default sound.
- Range
- C1–C7
- Sound
- Synthesised in your browser, no recordings
Pad
Detuned saws with a little noise, slow attack and release, LFO on the filter and delay.
- Range
- C1–C7
- Sound
- Synthesised in your browser, no recordings
8-bit square
One square wave, filter wide open, short envelope: the bright tone of early 8-bit consoles.
- Range
- C1–C7
- Sound
- Synthesised in your browser, no recordings
Bass
A square wave plus a saw an octave below, resonant filter, mono legato with a short glide.
- Range
- C1–C7
- Sound
- Synthesised in your browser, no recordings
Pluck
A saw plus a triangle an octave up; a fast filter envelope with no sustain, into a short delay.
- Range
- C1–C7
- Sound
- Synthesised in your browser, no recordings
Lead
Saw and square in mono legato with glide, gentle LFO vibrato and a light delay.
- Range
- C1–C7
- Sound
- Synthesised in your browser, no recordings
How the sound engine works
This is a digital synthesizer: nothing is recorded. Each note starts two oscillators, plus noise when a preset uses it, in the Web Audio API, through a resonant low-pass filter and an amplifier moved by the envelopes and the LFO. The page loads 0 KB of audio.
Input and polyphony
- Computer keyboard
- 61-note window, Shift for sharps, octave shift between C1–C6 and C2–C7
- Mouse and touch
- Click or tap any of the 73 notes from C1 to C7
- MIDI controller
- Browsers with Web MIDI, such as Chrome and Edge
- Polyphony
- Up to 16 notes at once, or mono legato with glide
Free Online Synthesizer — No Download, No Sign-Up
- Generated on your device Web Audio calculates every sound live in your browser, so there is nothing to install.
- Your patches stay local Notes, takes and rack settings never leave your device.
- No account, no paywall No email, no trial and no paid tier locking the filter or the LFO.
Online Synthesizer FAQ
Is this online synthesizer free?
Yes. The online synthesizer is free with no account, trial or time limit, and every control is open. Ads elsewhere on the page pay for it, never inside the instrument.
Can I play the synth with my computer keyboard?
Yes. Letters and numbers play a 61-note window and Shift plays the sharps. The octave buttons move the window between C1–C6 and C2–C7.
Can I connect a MIDI controller?
Yes. Plug in a USB MIDI controller, open the page in a browser with Web MIDI, such as Chrome or Edge, and turn on MIDI in the control bar.
Which synth sounds and presets can I choose?
Six presets: Analog-style, Pad, 8-bit square, Bass, Pluck and Lead. Each is just a set of rack settings, so every waveform, filter, envelope, LFO and delay control stays editable.
How does this synthesizer make sound?
Oscillators make a raw tone, a filter removes some brightness and an amplifier sets the level, while envelopes shape both over time. It is all generated live, from 0 KB of audio.
What do the waveform, filter, envelope and LFO controls do?
The waveform sets the basic tone, from a pure sine to a buzzy saw. Cutoff darkens or brightens it, resonance adds a peak, envelopes shape how each note starts and ends, and the LFO adds movement.
Do I need to download a synthesizer app?
No. This web synth runs in any modern browser on a computer, tablet or phone, with nothing to install. On a phone, the rack opens in one column below the notes.
What is the best online synthesizer?
Look for one that lets you shape a sound: a resonant filter, envelopes, an LFO, editable presets, recording and MIDI controller input. This synthesizer has all of them, free.
Can I play chords, or switch to mono with glide?
Yes. Most presets play up to 16 notes at once. Bass and Lead use mono legato, where each note slides into the next; set the mode and glide time in the rack.
Can I record what I play?
Yes. Press record, play, then stop and play the take back. It stores notes, not audio, so playback uses the current sound, even after you switch presets.