User Manual
Openloop Pay Mini Wallet

Openloop Pay

Haudi Crypto, Inc.

Version 0.8.2
2026-09-12

Contents

  1. Introduction
  2. Requirements
  3. Connecting a wallet
  4. Checking balances
  5. Manage tokens & networks
  6. Sending
  7. Loading a payment from a QR code
  8. Switching accounts
  9. History and CSV export
  10. dApp integration (extension only)
  11. Security
  12. Troubleshooting
  13. Specifications
  14. Contact

1. Introduction

Openloop Pay is a mini wallet that makes stablecoins easy to use. You can check balances and send crypto assets. It runs as a browser extension on your desktop and as a web app on your smartphone.

Supported tokens and networks are EVM chains (Ethereum and EVM-compatible chains) and TRON. Alongside the built-in stablecoins (JPYC / USDC / USDT / TUSD / USDD), you can add other tokens on the EVM chains. See §13 “Specifications” for the full list.

Your private keys stay inside your Openloop hardware wallet (or the wallet you connect); Openloop Pay never stores or accesses them (non-custodial).

Openloop Pay is a companion wallet that holds no keys of its own. The wallet itself (your keys) lives in your Openloop device or the wallet you connect over WalletConnect; Openloop Pay only shows balances and relays transactions for signing. So, unlike wallets that keep an (encrypted) key in the browser, even if the web app or extension were compromised, there are no secrets inside to steal.

1.1 Key features

Feature Description
Wallet connection Connect Openloop over USB / Bluetooth, or connect a supported wallet via WalletConnect
Balances View your token balances and your gas (fee) assets
Manage tokens & networks Choose which token × network to show and send; add and remove them
Sending Enter a recipient and amount, then approve with the connected wallet
QR scanning Read a payment-request QR code to pre-fill the send form
History Review send history and export it as CSV
dApp integration (extension only) Connect to dApps in your browser and approve requested signatures on your Openloop device

1.2 What you can connect

2. Requirements

Openloop Pay ships in two forms: a browser extension (Chrome/Edge only) and a web app (https://www.crypto.haudi.jp/openloop/pay/app/). Which connection methods the web app can offer depends on the browser.

2.1 Web-app support matrix

Environment USB (WebHID) Bluetooth (BLE) Safari-extension bridge WalletConnect
Desktop Chrome / Edge ✓ – – ✓
Desktop Firefox – – – ✓
Desktop Safari (macOS) – – ✓ (requires the macOS Openloop Connect) ✓
Android Chrome / Samsung Internet – ✓ – ✓
Android Firefox – – – ✓
iPhone / iPad Safari – – ✓ (requires iOS Openloop Connect) ✓
iPhone / iPad Chrome / Firefox / Edge – – – ✓

2.2 Extension version

2.3 Using Openloop Pay in Safari (iPhone / iPad / Mac)

Safari does not implement WebHID or WebBluetooth, so it cannot talk to an Openloop device directly. Enabling the Safari extension bundled with the Openloop Connect app bridges Safari to the Openloop device.

Device App to install Path to the Openloop device
iPhone / iPad iOS Openloop Connect Bluetooth
Mac macOS Openloop Connect USB

This manual only covers what Openloop Pay does. For the Openloop Connect app itself, see the Openloop Connect user manual.

The steps below are for iPhone / iPad.

Setup:

  1. Install “Openloop Connect” from the App Store (iPhone / iPad).
  2. Open Settings → Safari → Extensions.
  3. Tap Openloop Connect and switch it On.
  4. Set Permissions → All Websites to Allow (recommended). Or grant only crypto.haudi.jp from the “AA” button next to Safari’s address bar → Website Settings when you first open Openloop Pay.
  5. Reopen Openloop Pay. The connect screen will now list your Openloop over Bluetooth.

Important — open Openloop Pay in Safari itself, not from a Home Screen icon. If you use “Add to Home Screen”, iOS runs the web app in a standalone window that is isolated from Safari, and Safari extensions do not run inside it — so the Openloop Connect bridge is unavailable and Bluetooth appears greyed out. This is an iOS platform limitation and cannot be fixed by any Safari extension setting. Always open Openloop Pay from a normal Safari tab (https://www.crypto.haudi.jp/openloop/pay/app/). (WalletConnect, §3.3, still works from a Home Screen icon because it does not need the extension.)

On a Mac the connection is over USB. With the Safari extension bundled in the macOS Openloop Connect enabled, Safari can use an Openloop device plugged in over USB (not Bluetooth). Note that on a Mac without the extension enabled, USB cannot be selected on the connect screen — use WalletConnect (QR code) instead (§3.3).

The iOS Openloop Connect app also works as a WalletConnect-compatible wallet (§3.3), independently of the Safari extension. WalletConnect works whether or not the Safari extension is enabled.

2.4 QR code reading

3. Connecting a wallet

When you open the app, the “Connect a wallet” screen appears. Choose how to connect.

3.1 Connect over USB (desktop)

  1. Connect Openloop to your desktop with USB.
  2. Choose Openloop (USB).
  3. In the browser’s device chooser, select your Openloop (first time only).
  4. Once connected, that account’s balances appear.

▲ Plug in only one Openloop. If two or more Openloop devices are connected over USB, the app cannot choose which one to use — so it may show the address and balances of a device you never picked (this can happen if, say, a second one is plugged in just to charge). Leave only the device you want to use plugged in, and unplug the rest.

The browser’s USB device chooser may not open inside the extension’s side panel. In that case, connect from a full tab. Once you’ve granted access, it reconnects without the chooser next time.

3.2 Connect over Bluetooth (smartphone)

  1. Turn on Openloop and enable Bluetooth.
  2. Start connecting in the app and pick your Openloop from the list.
  3. After pairing, that account’s balances appear.

The name in the list depends on your environment.

Environment Chooser Example
Android (Chrome) The browser’s own Bluetooth chooser Openloop (30:ED:A0:D4:BE:F6)
iPhone / iPad (Safari) Openloop Pay’s own list Openloop-BEF6
(for reference) Openloop Connect app The app’s own list Openloop-BEF6

On Android the browser’s chooser is used, so the device name appears simply as Openloop; when several are found the browser appends the Bluetooth address to tell them apart. On iPhone / iPad, Openloop Pay draws the list itself, so you see the same Openloop-BEF6 form as in Openloop Connect.

All of these are the same device. The last four characters (BE:F6 → BEF6 in the example) correspond. Use this to tell them apart if you own more than one Openloop.

3.3 Connect via WalletConnect

  1. Choose WalletConnect.
  2. Pick the wallet you want to connect (e.g. Openloop Connect) from the list, or scan the QR code.
  3. Approve the connection on the wallet’s side.

Right after connecting, the selected wallet may still be on the network it used last. If the network isn’t switched automatically when you send, set the network on the wallet’s side.

On macOS Safari you have to allow pop-ups. Safari blocks pop-up windows by default. When you pick Desktop (the Openloop Connect desktop app) from the WalletConnect list, Openloop Pay only opens the app after finishing a round trip to the relay server — and Safari treats a window opened that long after your click as a pop-up and blocks it, so nothing happens when you choose it. Open Safari’s Settings → Websites → Pop-up Windows and set crypto.haudi.jp to Allow. You do not need this if you connect to Openloop Connect on your phone by scanning the QR code, or if you use Chrome / Edge.

4. Checking balances

Once connected, the main screen shows:

You choose which tokens and networks appear under “Assets” in the next chapter, “Manage tokens & networks.” Gas native tokens appear automatically for the networks your assets are on, so you normally don’t need to select them separately.

4.1 Showing testnets

Turn on Show testnets to add testnet tokens and networks to the list (their gas coins are shown too). This is useful for testing. When it’s off, testnets appear neither in balances nor in the lists. Leave it off for normal use.

5. Manage tokens & networks

This screen is where you choose which tokens — and on which networks — to show and send. Open it from the Manage tokens & networks link on the connect screen, or the manage button (coin icon) on the balances screen.

The screen is divided into sections. The basic rule is: built-in items (shipped with the app) can’t be removed; added items (ones you brought in) can. Alternating sections have a tinted background to keep them visually separate.

Each screen has a breadcrumb at the top (e.g. Home › Manage tokens & networks › Add a token) so you can see where you are. Tap any crumb to jump straight to that screen. Back goes up one level.

5.1 Adding a token

  1. Press Add a token.
  2. Search by symbol or name.
  3. Pick a result to see the networks that token is available on.
  4. Check the networks you want to add it on (you can pick several). It’s added the moment you check it.

The network list also shows, dimmed, the networks where that token is available as a built-in token. You can see which of them are currently selected, but you can’t change them here — change those in the “Built-in tokens” section.

Networks this app has no RPC endpoint for can’t read balances or broadcast, so they aren’t listed. For a token or network that isn’t listed, use “Not found? Add manually” to enter a contract address or RPC by hand (at your own risk — shown as “unverified”).

5.2 Confirming a removal or a deletion

Anything that takes an entry off your list asks first. Removing and deleting are treated as different things.

Action What happens Confirmation title
Unchecking a box Only the selection goes. The definition stays, so checking it again brings it back Remove from your list
🗑 on an added token The definition itself is deleted. To use it again you must re-enter its address and decimals Delete token
🗑 on a network The network and the tokens on it are deleted Delete network

5.3 Export / import settings

Buttons at the bottom let you export / import your token and network settings (as a JSON file) — handy for moving your setup to another device. Importing shows a confirmation that it will overwrite your current settings, along with an integrity check.

Anything that could not be imported is listed with the reason (no endpoint could be determined / it has no name and currency symbol / its explorer URL does not start with https:// / it matches an entry in Openloop’s own table, and so on). Nothing is dropped silently.

6. Sending

6.1 Steps to send

  1. In the send panel, choose the token (currency × network) you want to send.
  2. Enter the recipient (type an address, or pick one from the address book).
  3. Enter the amount. You can only enter it down to that token’s number of decimal places (USDC: 6, JPYC: 18). Anything finer leaves Send disabled.
  4. Press Send.
  5. A confirmation screen appears. Check the recipient (shown in full), the amount, and the network.
  6. Press Approve and sign with the connected wallet (e.g. the Openloop device).
  7. When the send completes, the transaction ID and a link to the block explorer are shown.

6.2 About the confirmation screen

6.3 Address book

You can save a recipient with a label of your choice. Next time, just pick it from the address book to fill in the recipient.

7. Loading a payment from a QR code

When you read a payment-request QR code, the send panel’s fields (token, recipient, amount) are filled in automatically. There are two ways to read it.

7.1 Read with the in-app scanner

  1. Press the QR button at the top right of the send panel.
  2. The camera starts; point it at the QR code (it reads automatically).
  3. If the camera isn’t available, you can paste the code instead.

7.2 Read with the stock camera (printed QR)

A printed payment link posted by a store can be read with your phone’s stock camera. It shows a link; tapping it opens Openloop Pay with the payment pre-filled.

7.3 What happens after reading

A standard format (EIP-681) is used so printed paper QRs work. Split QR formats like BBQr are not used.

8. Switching accounts

A single Openloop has multiple accounts. Use Switch account on the wallet card to change which account is shown and used for sending.

9. History and CSV export

Your send records appear in the History on the main screen.

History is stored only on your device (browser). It is never sent to any external server.

10. dApp integration (extension only)

The browser-extension build of Openloop Pay can connect directly to dApps (decentralized apps) on the web. Connection and signature requests from a dApp are relayed through Openloop Pay to your Openloop device, where you always review and approve the final action on-device.

The web app and the smartphone build do not integrate with dApps. To connect to dApps, install the Openloop Pay extension in your desktop browser.

10.1 How dApp connections work

10.2 See which sites are connected

You can check the list of sites currently allowed to see your wallet at any time.

  1. Tap ⓘ to open the Info screen.
  2. Choose Settings ›.
  3. Choose dApp connections ›.
  4. Every connection is listed, each showing the tab number and connect time, plus the site’s host name.

Connections are per browser tab. Opening and connecting the same site in more than one tab creates a separate connection on its own row (in the example above, app.uniswap.org appears twice — as “Tab 1” and “Tab 3”). Closing a tab automatically ends that tab’s connection, and disconnecting is done per tab.

10.3 Disconnect one tab, or disconnect all

10.4 When the side panel is closed

If a dApp requests an action (signing, switching accounts, …) while the Openloop Pay side panel is closed, a small hint popup appears. Press Open to open the side panel, then retry the action in the dApp.

11. Security

Openloop Pay is built to help you send safely.

11.1 Precautions

12. Troubleshooting

The camera isn’t available / permission is denied
Allow camera use in your browser settings. You may be able to allow it from the camera icon in the address bar. Some browsers (such as an extension side panel) can’t use the camera; in that case, paste the code instead.
An address or balance I don’t recognise is shown (USB)
Check whether two or more Openloop devices are connected over USB. With more than one connected, the app cannot choose which to use and may show the one you didn’t pick. Leave only the device you want to use plugged in, unplug the rest, and connect again.
The USB Openloop doesn’t appear in the chooser (extension)
The USB chooser may not open in the extension side panel. Try connecting from a full tab. Also, if Openloop Connect or similar is using the same device, USB may be occupied and unavailable.
A network I want to add isn’t listed
Networks this app has no RPC endpoint for can’t read balances or broadcast, so they aren’t listed. If you know the RPC, add it by hand from “Not found? Add manually.”
WalletConnect shows “cannot connect”
The connection may be taking time to establish. Wait a moment and try again.
The send confirmation won’t close / there’s no response
It’s waiting for a response from the connected wallet. Close it with Cancel and try again.
The network doesn’t match
The WalletConnect wallet may be on a different network than the one you want to send on. Set the network on the wallet’s side.

13. Specifications

13.1 Supported tokens (built-in)

Openloop Pay supports tokens on EVM chains (Ethereum and EVM-compatible chains) and on TRON. The following five stablecoins ship built in and are ready to send and receive without any setup.

Token Supported mainnets
JPYC Ethereum / Polygon / Avalanche C-Chain / Kaia (4 chains)
USDC Ethereum / Polygon / Avalanche C-Chain / Base / Arbitrum One / OP Mainnet / TRON (7 chains; on the EVM chains this is Circle-issued native USDC)
USDT Ethereum / Polygon / TRON (3 chains)
TUSD TRON (1 chain)
USDD TRON (1 chain)

Testnet JPYC ships on Sepolia / Polygon Amoy / Avalanche Fuji / Kaia Kairos (4 chains — enable Show testnets, §4.1). On the TRON testnets (Shasta / Nile) a test tUSDT is provided.

TRON tokens cannot be added. The five built-in entries above (the TRON column) are the full set. The dictionary search and manual add described in §13.3 are for the EVM chains only.

13.2 Supported networks (built-in)

Type Networks
Mainnets (8) Ethereum / Polygon / Avalanche C-Chain / Base / Arbitrum One / OP Mainnet / Kaia / TRON
Testnets (3) Sepolia / Polygon Amoy / Base Sepolia

The TRON testnets (TRON Shasta / TRON Nile) are treated as added networks, the same as Avalanche Fuji. Selecting them in a built-in token’s network column enables them.

Each network ships with a public RPC endpoint (publicnode family) and a block-explorer URL.

The TronGrid endpoints for TRON ship with the app and cannot be changed.

13.3 Added tokens and networks

This whole section is EVM-only. On TRON you can neither add tokens nor change the endpoint (§13.1, §13.2).

13.4 dApp integration (extension only)

The browser-extension build talks to dApps over the following standards.

Item Supported
Provider API EIP-1193 (the window.ethereum interface)
Provider discovery EIP-6963 (Multi Injected Provider Discovery — coexists with other wallets)
Chain ID EIP-155 / CAIP-2
RPC methods eth_requestAccounts / eth_accounts / eth_chainId / eth_sendTransaction (EIP-1559 type-2 tx) / personal_sign / eth_signTypedData_v3 / eth_signTypedData_v4 (EIP-712) / wallet_switchEthereumChain (EIP-3326) / wallet_addEthereumChain (EIP-3085)
Not supported eth_signTypedData_v1 (legacy — dropped, no type info) / eth_sign (blind-signing of an opaque hash — a strong red warning is shown if requested)
Access grants Granted and revoked per tab (the tab where a dApp is open) (§10)

13.5 WalletConnect

13.6 Payment-request QR

13.7 Web app vs. browser extension

Item Web app Browser extension (Chrome / Edge)
Runs on Desktop and smartphone Desktop only
Openloop (USB) Yes (WebHID-capable browser) Yes (may need full-tab consent)
Openloop (Bluetooth) Yes (supported smartphones) No (blocked by extension permissions)
WalletConnect Yes Yes
dApp integration (EIP-6963 / EIP-1193) No Yes
Camera QR scan Yes Limited (may not work in the side panel)
Open from payment link Yes Yes
Storage for history / address book In the browser In the extension storage

14. Contact

If you have any questions or trouble, please contact us.

Haudi Crypto, Inc. Email: support@crypto.haudi.jp

You can also open the version, links to each document, and the settings screen (payment sound, dApp connections) from the in-app info (ⓘ) button.

Related documents: Terms of Service / Privacy Policy / Licenses