This MIDI tester shows everything your MIDI keyboard, drum pad or controller sends, the moment it sends it. Connect the device, press Connect MIDI and play: notes light up an on-screen piano and play through a built-in sound, the pitch bend and mod wheels move their meters, and a live monitor decodes every message with its channel, note name, velocity and raw bytes. It also sends test notes to synths and interfaces, measures MIDI clock tempo and jitter, and times a loopback through your cables. It works with USB MIDI and 5 pin MIDI through an interface, in Chrome, Edge, Opera and Firefox on Windows, Mac, Linux and ChromeOS, and in Chrome on Android.
How to test a MIDI keyboard
- Connect the keyboard with a USB cable that carries data, or connect its MIDI OUT to the IN of a USB MIDI interface.
- Close your music software, then press Connect MIDI and allow MIDI devices when the browser asks.
- Check that the keyboard appears under Inputs. Its light flashes yellow with each message.
- Play every key from bottom to top, softly and hard. Each key should light and sound, and Velocity should follow how hard you play.
- Move the pitch bend and modulation wheels, press the sustain pedal, turn every knob and slider and press the pads. Each one should show in the monitor.
- To test an output, choose it under Send to and press Test note.
What the readouts mean
| Readout | What it shows | Normal |
|---|---|---|
| Note | Name of the last note played, middle C is C4 | Matches the key you pressed |
| Velocity | How hard the key was struck, 1 to 127 | Low when soft, near 127 when hard |
| Channel | MIDI channel of the message, 1 to 16 | Usually 1 |
| Pitch bend | Wheel position, from -8,192 to +8,191 | Returns to 0 when you let go |
| Clock tempo | Tempo worked out from MIDI clock messages | Matches the sending device |
| Clock jitter | How much the time between clock ticks varies | Under 1 ms is very good |
| Loopback delay | Time for a note to go out and come back in | 1 to 5 ms over USB |
MIDI messages in the monitor
| Message | Sent by | Data shown |
|---|---|---|
| Note on and note off | Keys and pads | Note name and velocity. A note on with velocity 0 counts as note off |
| Control change | Knobs, sliders, pedals, mod wheel | Controller number and value, 0 to 127. Sustain is CC 64 |
| Pitch bend | Pitch bend wheel or strip | Position, 0 in the center |
| Aftertouch | Pressing harder on held keys | Pressure, for the channel or for each key |
| Program change | Patch and preset buttons | Program number, 1 to 128 |
| Clock, start and stop | Drum machines, sequencers, DAWs | 24 clock ticks per beat |
| Active sensing | Many Roland and Yamaha keyboards | A heartbeat every 300 ms, hidden by default |
| SysEx | Editors and some controllers | Maker ID and length, needs Allow SysEx |
MIDI keyboard not detected
If nothing appears under Inputs, the computer is not seeing a MIDI device:
- The cable only charges. Many USB cables have no data wires. Use the one that came with the keyboard or one you know carries data.
- Another program has it open. With the classic Windows MIDI system, only one program can use a MIDI device at a time. Close your DAW, then press Connect MIDI again. The tester marks such inputs as in use.
- It needs a driver. Most current keyboards are class compliant and need no driver on Windows, macOS, Linux, Android or iPad. Some older Roland, Korg and M-Audio models need the maker's driver. Check the support page for your model.
- Power. Larger keyboards may need their own power supply. Plug a bus powered controller straight into the computer rather than a hub.
- The keyboard's USB mode. Some keyboards switch between USB audio, MIDI and storage modes in their settings. Choose MIDI.
- Check the system sees it. On Windows, it appears in Device Manager under Audio inputs and outputs or Sound, video and game controllers. On a Mac, open Audio MIDI Setup and choose Window, then Show MIDI Studio. On Linux, run
amidi -l. If Windows shows an unknown USB device, the usb device not recognized guide helps.
Notes show here but not in your music software
If the tester sees your keyboard but your DAW stays silent, the DAW is not listening to that input:
- Ableton Live: Settings, then Link, Tempo & MIDI. Under MIDI Ports, turn on Track for your keyboard's input. Arm or select a MIDI track with an instrument.
- FL Studio: Options, then MIDI settings. Select the keyboard in the Input list and click Enable.
- Cubase: Studio, then Studio Setup, then MIDI Port Setup. Tick the keyboard in the In All MIDI Inputs column.
- REAPER: Options, then Preferences, then Audio, then MIDI Inputs. Right-click the keyboard and choose Enable input, then record arm a track with its input set to the keyboard.
- Logic Pro and GarageBand: both use every connected keyboard automatically. Select a software instrument track.
No sound, stuck notes or wrong notes
- No sound from the tester: click once anywhere on the page, since browsers only start sound after a click, and check the Sound switch and volume. If other sites are silent too, run a headphone test.
- A note keeps sounding: press All notes off. Stuck notes come from a lost note off message, often through a loose cable or a cheap USB MIDI cable.
- The sustain pedal works backwards: sound sustains until you press the pedal. The pedal's polarity is reversed. Switch the keyboard off, plug the pedal in, then switch it on without touching the pedal, or set the polarity switch on the pedal.
- Velocity is always 127 or barely changes: the keyboard has a fixed velocity setting or a hard velocity curve. Change it in the keyboard's settings.
- The DAW plays the wrong instrument: the keyboard sends on a channel the track is not set to. Read the Channel readout here and match it.
Test MIDI outputs, cables and timing
To check an interface's MIDI OUT, connect it to a synth, choose it under Send to and press Test note or Play a scale. For a full round trip, link the interface's MIDI OUT to its MIDI IN with a cable, choose that output and press Loopback test. The tester sends 40 notes and reports how many came back, the average delay and the jitter. On a Mac you can loop through the IAC Driver, and on Windows through a loopback port such as loopMIDI, to measure the computer's own delay. Cheap no-name USB MIDI cables often drop notes and SysEx data, which this test shows as missing notes.
When a drum machine, sequencer or DAW sends MIDI clock, Clock tempo and Clock jitter show how steady it is. Timing problems you can hear in a recording may also come from audio delay, which the audio latency test measures. Tools with a serial port rather than MIDI, such as an Arduino building a MIDI controller, can be checked with the serial port tester first.
Safari, iPhone and iPad
Safari does not support MIDI devices for web pages. Apple decided against it because the list of connected devices could help sites fingerprint visitors. Every browser on iPhone and iPad uses Safari's engine, so none of them can run this test. On a Mac, use Chrome, Edge, Opera or Firefox. Firefox asks you to add a small site permission the first time, which is normal.
What this MIDI test cannot check
The tester only sees messages, so it cannot check a keyboard's audio outputs or speakers, and it does not test MIDI 2.0 features. Bluetooth MIDI devices must be paired in your system's MIDI settings before a browser can see them. To check the pitch a keyboard actually plays through its speakers, use the pitch detector. The computer's own keys are a different device: for those, use the keyboard tester.
MIDI tester questions
How do I test if my MIDI keyboard is working?
Connect it, press Connect MIDI on this page and allow MIDI when the browser asks. The keyboard should appear under Inputs. Play every key: each one lights the on-screen piano and makes a sound. Then move the pitch bend and mod wheels, press the sustain pedal and turn each knob, and watch them in the monitor.
Does this MIDI tester play sound?
Yes. Incoming notes play through a built-in piano, organ or synth voice with velocity, sustain pedal and pitch bend, so you can hear your keyboard without a music program. Turn it off with the Sound switch.
Why is my MIDI keyboard not showing up?
Usually a charge-only USB cable, a music program that already has the keyboard open on Windows, or a keyboard that needs its maker's driver. The section on keyboards that are not detected covers each one.
Why does middle C show as C3 in my music software?
There is no single standard. This tester calls note 60 C4. Ableton Live, Logic Pro, Cubase and Yamaha keyboards call the same note C3, and FL Studio calls it C5. The note number is what matters, and the monitor shows it in the Bytes column.
Can I test MIDI on an iPad or iPhone?
Not in a browser. Apple's Safari engine does not support MIDI devices for web pages, and every iPhone and iPad browser uses it. GarageBand on the iPad responds to a connected MIDI keyboard, which is a quick check that it works.
What is a good MIDI latency?
A USB MIDI round trip through a loopback cable is usually 1 to 5 ms, and steady timing matters more than the average. Clock jitter under 1 ms is very good. Tens of milliseconds point to a cheap adapter, a busy USB hub or Bluetooth MIDI.