Six short guides: getting the browser to hand over your MIDI devices, one per device family, and how saving works. No account, no install, nothing uploaded.
Get MIDI working read this first
The editor talks to your pedal through the browser. The browser will not do that until you say yes, and it asks exactly once — quietly, under the address bar. Missing that prompt is the single most common reason the page “does nothing”, and it is not a bug in the pedal or the page.
Before you start
Chrome or Edge on a desktop or laptop. Firefox needs an add-on for Web MIDI. Safari, and every browser on iPhone and iPad, cannot do it at all.
A real cable. The Katana has no Bluetooth — USB only. Valeton GP-5/GP-50 and the Pocket Master connect over Bluetooth; the GP-200 generation wants USB.
https. Browsers disable MIDI on plain http:// pages, except on localhost.
The three ways it goes wrong
You never saw the prompt. Look under the address bar for a small permission bubble, or click the icon just left of the address (a tune icon or a lock), open MIDI devices, and choose Allow. Then reload with F5 — Chrome only applies a changed permission on load.
You dismissed it once and now it is blocked. Same icon, same menu, set it back to Allow, reload, pick your device again.
You allow it and still nothing appears. Then the permission is fine and the problem is the port: the pedal is not in the list. Check the cable, check the pedal is on, and check no other program (Tone Studio, a DAW, the vendor app) has the port open — MIDI ports are usually exclusive.
The page shows a card with a button whenever it is waiting on you. Press it — a browser can only re-ask for MIDI while you are clicking, never on its own.
What you should see
After allowing: the port dropdowns fill in within a second, the device name appears, and Connect stops being greyed out.
BOSS Katana MkII verified
The Katana is a class-compliant USB-MIDI device. No BOSS driver, no Tone Studio, no Adobe AIR.
Connect the amp with a USB cable and switch it on. Use a data cable, not a charge-only one.
Pick BOSS Katana at the top of the page, press Connect, and allow MIDI if asked.
Wait for the amp to identify itself. The page asks before it writes anything — that identity check is what keeps a MkII write off a Gen3.
Read: every block on the amp loads into the editor. Edit: change a value and it goes to the amp as you turn the knob.
What is confirmed, and what is not
MkII — read and write, confirmed on the bench.
MkI and Gen3 — the editor uses its best documented knowledge for these. You are testing it; expect to find gaps and please report them.
Katana GO and Air — BLE-MIDI adapters, see the scan page. Air has no Bluetooth of its own; it needs a BLE-MIDI adapter in the USB port.
Saving: pick a channel first (PANEL, A1–A4, B1–B4), then save. PANEL has no memory of its own, so a save aimed at PANEL is refused rather than silently dropped.
Valeton GP-5, GP-50, GP-200 GP-5 verified
GP-5
Power the pedal on and put it in its normal play screen.
Pick Valeton GP-5, press Connect, and choose the pedal in the browser's Bluetooth dialog.
Wait for the patch name to appear at the top. That is the page confirming it is talking to the pedal, not to a stale session.
Everything on the pedal's own screen has a control here: on/off for each block, effect type, and every parameter the firmware exposes — with real units (ms, Hz, kHz) and signed values on the bipolar bands.
Confirmed on hardware: patch list, parameter writes, block toggles, effect changes, save and rename. If a write does not take, the pedal answers with the value it actually holds, and the page shows that instead of pretending.
GP-50 pilot
The GP-50 uses the same SysEx codec as the GP-5 — the same builders, the same framing. It has not been confirmed on a GP-50 yet. It is public so you can be the one who confirms it.
Connect it the same way as the GP-5, over Bluetooth.
What we need to know: does the patch list populate, and does a parameter change hold on the pedal?
If it connects but the list stays empty, that is the useful result — tell us and it goes in the queue.
GP-200 handshake only
We know the GP-200's handshake and nothing else: identity, editor mode, a state request. Patch reading and parameter writing are not implemented. An empty editor here is the expected result, not a bug — the connection itself is what we are testing.
The GP-200 generation is USB-MIDI (plus 5-pin MIDI on the larger units), so it appears as a normal MIDI port — no Bluetooth step.
Zoom G5n and MS-200D+ G5n verified
Connect the pedal by USB and switch it on.
Pick the family, Connect, allow MIDI.
On the G5n, the parameter panel opens from the editor and shows every parameter the pedal exposes, with switches drawn as switches rather than knobs.
Edits go straight to the pedal; the patch itself is stored on the pedal, as it always was.
The MS family (MS-50G, MS-60B, MS-70CDR, MS-200D+) shares the transport and has its own editor.
Mooer / NUX Pocket Master BLE
Power the pedal on and make sure nothing else is connected to it over Bluetooth — a phone with the vendor app open will hold the connection.
Pick Pocket Master, press Connect, and choose it in the browser's Bluetooth dialog.
Reading is silent: the page asks the pedal for its patch without switching channels, so your amp does not jump while you look around.
Bluetooth on a desktop needs Chrome or Edge. On a Mac, Bluetooth permission is granted per browser, in System Settings → Privacy & Security → Bluetooth.
Saving, and what the site never does
A patch is storage on the pedal. There is no “delete patch” here on purpose: every slot always holds bytes, so deleting would make the library lie about what the pedal has.
Saving writes the channel you chose. Check the channel before you save — that is the one action that overwrites something.
Nothing is uploaded. No account, no sign-up, no patch library on a server. Reload and the pedal is still the only copy — which is also why an unfinished edit disappears if you close the tab.
Anonymous usage counts. The page reports which device was picked and whether a connection worked, so a device family with a real problem is visible. No patch content, no names, no personal data.
Something broken?Report it — a sentence about the pedal and what you expected is enough.