Skip to main content
The Tonhub application implements two cryptocurrency exchange options:

​
General Access Scheme

  • “Exchange” / “Swap” Screen: from the main screen or products section, users can navigate to exchange method selection. When selecting “Exchanges”, a partner selection screen opens: DeDust.io and Changelly.
  • DeDust: clicking opens a fragment with WebView at https://tonhub.dedust.io/ (integration via TON Connect). Available only for regular wallets; when accessing through Ledger, the DeDust option is not displayed in the exchanges list.
  • Changelly: clicking opens a native exchange flow (select “receive” currency → select “send” currency → enter amount → create order → order screen with deposit address). Additionally, the app provides a Changelly widget (separate screen with WebView on widget.changelly.com). Changelly is available for both regular wallets and Ledger.

​
Changelly Integration

Changelly — a partner cryptocurrency exchange service. Users specify a currency pair (what to send / what to receive) and amount; receive a deposit address and after funds arrive — exchange to the selected currency. In Tonhub, the integration is implemented as a widget (Changelly page in WebView).

​
Exchange Process

  • Through “Exchanges” → select “Changelly” → opens a separate screen with WebView on widget.changelly.com Swap (select the asset the user wants to receive).
  • On the Swap screen, users select one of the currencies: TON, USDT (usdton), SOL, USDC (Solana). After selection, the “send” currency list opens (ChangellyListFragment) — list of Changelly-supported currencies for exchange to the selected one. This is followed by calculation (amount input, estimation, fees) and transaction creation through the Tonhub backend API. After creation, users proceed to the order screen (ChangellyOrderFragment): deposit address (payin), amount, rate, status. Users send funds to the specified address; the app can poll order status (resolve) and display updates.
  • Widget: separate screen (ChangellyFragment) opens https://widget.changelly.com with parameters (e.g., fromDefault: ton, toDefault: usdton, merchant_id, v: 3). Before first opening, users accept Changelly’s terms and policy (flag saved locally). Widget is only available in mainnet; in testnet, a message is displayed that the service is only available in mainnet.

​
API and Backend

All Changelly requests go through the Tonhub backend (connect.tonhubapi.com), the app does not call Changelly API directly:
  • GET /changelly/currencies?currencyTo= — list of currencies that can be exchanged for the selected one (currencyTo: USD, SOL, USDC, etc.). Response contains an array of currencies with fields ticker, name, image, blockchain, network, etc.
  • POST /changelly/estimate — exchange estimation: request body { toCurrency, fromCurrency, amount }. Response includes amount to receive, fees, rate, limits (min/max). The app checks limits and displays an error when exceeded (ChangellyLimitError).
  • POST /changelly/transaction/create — create exchange order. Request body: fromCurrency, toCurrency, network, amount, idempotencyKey, wallet (user’s wallet address). Response includes order data: payinAddress, payoutAddress, amountExpectedFrom, amountExpectedTo, networkFee, status, etc. Upon creation (in mainnet), an analytics event may be sent (e.g., Maestra).
  • POST /changelly/transaction/details — get order details by identifier.
  • POST /changelly/transaction/resolve — update/resolve order status (e.g., after user deposit).
  • POST /changelly/transactions — list of user’s exchange transactions (request body with address/parameters).
In the order, users see payinAddress (address to send the source currency to), order expiration (expiresAt), statuses (new, waiting, confirming, exchanging, sending, finished, failed, refunded, hold, expired, overdue, resolved). After sending funds, the app periodically requests status updates and displays results upon successful completion.

​
DeDust Integration

DeDust — a decentralized exchange (DEX) and interface for swaps in the TON network (including TON:left_right_arrow: tokens). In Tonhub, the integration is implemented by opening the DeDust partner page in WebView with wallet parameter substitution and TON Connect for transaction signing. All swap logic (pair selection, calculation, transaction sending) is performed on the DeDust website side; the app only provides the wallet and bridge.

​
DeDust Access

  • Through “Exchanges” → select “DeDust.io” → opens DedustFragment. DeDust is displayed in the exchanges list only if the wallet is not Ledger; when accessing through Ledger, the DeDust option is hidden.
  • Opens page https://tonhub.dedust.io/ with substituted query parameters:
    • address — current TON wallet address (bounceable depending on user setting).
    • utm_source, utm_content, ref — tonhub, extension, tonhub (source tag).
    • lang — current app language.
    • currency — user’s selected primary currency (for displaying equivalents).
    • themeStyle — light / dark according to app theme.
    • pushNotifications — true/false depending on push notification permission.
A TON Connect-compatible bridge is injected into WebView (tonhubBridgeSource + injectionEngine): the DeDust page can call connect, sendTransaction, signData, etc., requests are processed by the app, users confirm operations in Tonhub. Thus, users remain in the app while the swap is executed on DeDust’s side with transaction signing through Tonhub. On first DeDust opening, a terms confirmation screen is displayed (ConfirmLegal): title, description, links to DeDust’s terms and privacy policy (tonhub.dedust.io/docs/…). After acceptance, the flag is saved in local storage (skipLegalDeDust key), and on subsequent launches, WebView opens immediately.

​
Useful Links

Changelly DeDust