Ton Appkit

AppKit Guide

Guide developers consuming @ton/appkit + @ton/appkit-react in their TON apps. Assume React, TypeScript, and TanStack Query basics, but explain TON/AppKit-specific decisions clearly.

For contributing to the @ton/kit monorepo, use kit-dev instead. This skill is for library-consumer answers: code the user's app would write, not package internals.

Response workflow

1. Classify the task first. If the user wants a complete feature quickly, prefer drop-in components. If they describe custom UX, use hooks. If they report stale data, real-time, network, or SSR symptoms, start with the relevant gotcha before writing code.
2. Give runnable integration shape. Include provider setup when the bug could come from missing QueryClientProvider, AppKitProvider, connector config, CSS import, or streaming providers. Avoid isolated hook snippets that omit required context.
3. Use AppKit semantics exactly. Balances are already-formatted decimal strings (TON or jetton units — never raw nano), transfer amounts are human-readable strings, mutations do not automatically invalidate caches, streaming is opt-in, and wallet state is client-only for SSR.
4. Name the tradeoff. Drop-in components are fastest and safest; hooks are for custom UX and require explicit loading/error/cache handling.

What do you want to do?

Drop-in components (<TonConnectButton />, <SendTonButton />, <SwapWidget />, etc.) are the fastest path. Use hooks only for custom UX.

For extended swap/staking/jetton recipes, see skill-reference/recipes.md.

Packages

• @ton/appkit — core SDK: AppKit class, actions, connectors (TonConnect), DeFi managers.
• @ton/appkit-react — React hooks, AppKitProvider, UI components.
• @tanstack/react-query — required peer dependency.

Quick Setup

import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
import { AppKit, Network, createTonConnectConnector } from '@ton/appkit';
import { AppKitProvider } from '@ton/appkit-react';
import '@ton/appkit-react/styles.css';

const queryClient = new QueryClient({
    defaultOptions: { queries: { refetchOnWindowFocus: false } },
});

const appKit = new AppKit({
    networks: {
        [Network.mainnet().chainId]: {
            apiClient: { url: 'https://toncenter.com', key: 'YOUR_API_KEY' },
        },
        // Keep testnet too so users on testnet wallets aren't silently rejected.
        // Drop it once you're production-only.
        [Network.testnet().chainId]: {
            apiClient: { url: 'https://testnet.toncenter.com', key: 'YOUR_API_KEY' },
        },
    },
    connectors: [
        createTonConnectConnector({
            tonConnectOptions: { manifestUrl: 'https://your-app.com/tonconnect-manifest.json' },
        }),
    ],
});

// QueryClientProvider MUST wrap AppKitProvider
function App() {
    return (
        <QueryClientProvider client={queryClient}>
            <AppKitProvider appKit={appKit}>{/* your app */}</AppKitProvider>
        </QueryClientProvider>
    );
}

For Next.js: add 'use client' to the providers file and gate wallet-dependent UI until mount, or use dynamic(() => import(...), { ssr: false }). There is no ssr flag on AppKitConfig — the SSR boundary is purely a React/Next concern, not an AppKit option. Wallet state (useAddress, balances, etc.) is client-only by construction; render a stable placeholder on the server and swap in wallet-dependent UI after useEffect/mount.

Browser polyfills (Vite / Webpack / Rspack)

@ton/core (transitive dep) uses Node's Buffer and process. Browser bundlers don't include these by default — without polyfills you get a white screen and ReferenceError: Buffer is not defined at runtime.

For Vite, install vite-plugin-node-polyfills and add it to vite.config.ts:

import { defineConfig } from 'vite';
import react from '@vitejs/plugin-react';
import { nodePolyfills } from 'vite-plugin-node-polyfills';
export default defineConfig({ plugins: [react(), nodePolyfills()] });

If the plugin clashes with your project (e.g. nested workspace, alias resolution warnings), use a manual polyfill instead — pnpm add buffer process, then create src/polyfills.ts:

import { Buffer } from 'buffer';
import process from 'process';
(globalThis as { Buffer?: typeof Buffer }).Buffer = Buffer;
(globalThis as { process?: typeof process }).process = process;

Import ./polyfills as the first line of main.tsx (before any AppKit code).

Next.js: no polyfill needed — Next's Webpack config handles Node globals automatically.

First-touch send: self-transfer

For a safe end-to-end test of the send flow, use useAddress() as the recipient — the user sends 0.01 TON to themselves. Validates wallet, network, signing, and on-chain confirmation without risk:

const address = useAddress();
{address && <SendTonButton recipientAddress={address} amount="0.01" />}

For real recipients, paste a TON address from Tonkeeper (UQ… non-bounceable for wallets, EQ… bounceable for contracts). Random/made-up strings without valid checksums make Tonkeeper's simulator say "no changes to your account" and refuse to sign.

Hooks Reference

Hooks come from @ton/appkit-react. Queries return TanStack { data, isLoading, isError, error }. Mutations return { mutate, mutateAsync, isPending, error, data, reset }.

Wallet

useConnectors() · useConnect() · useDisconnect() · useSelectedWallet() · useAddress() · useConnectedWallets()

useConnect() returns a mutation; call it with mutate({ connectorId }), passing the connector's id from useConnectors() (not the connector object itself). On iOS, the deep link that opens the wallet only fires if connect() runs in the same synchronous tick as the user's click — any await before it kills the user-activation token and the wallet won't open.

const connectors = useConnectors();
const { mutate: connect, isPending } = useConnect();

// ✅ Good: synchronous in click handler
<button => connect({ connectorId: connector.id })}>Connect</button>

// ❌ Bad on iOS: awaiting before connect() loses the user gesture
<button () => {
    await analytics.track('connect_clicked'); // <-- breaks deep link on iOS
    connect({ connectorId: connector.id });
}}>Connect</button>

If you need side effects, fire-and-forget them (no await) or run them in mutation: { onSuccess }.

Balance & assets

• useBalance() / useBalanceByAddress({ address, network? }) — returns a decimal TON string already formatted with 9 decimals (e.g. "0.500000000" for a wallet holding 0.5 TON). It is NOT raw nano and NOT a bigint. Render directly or format with Intl.NumberFormat; do not pass it through formatUnits(_, 9) again — that re-slices on the decimal point and yields garbage like "0..500000000". Pass network explicitly for cross-network reads: useBalanceByAddress({ address, network: Network.testnet() }).
• useWatchBalance() / useWatchBalanceByAddress(...) — real-time updates (requires streaming provider)
• useJettons() — returns { jettons: Jetton[], addressBook }. Use data?.jettons, not data directly. Each Jetton.balance is already formatted via the jetton's own decimalsNumber (e.g. "1.5" for 1.5 USDT) — same rule: don't re-format with formatUnits. Image URLs live under info.image.smallUrl / info.image.url (note the Url suffix).
• useJettonBalanceByAddress({ jettonAddress, ownerAddress, jettonDecimals?, network? }) — note the param is ownerAddress, not address. Returns a pre-formatted decimal string in the jetton's own units (e.g. "1.5" for 1.5 USDT). If jettonDecimals isn't passed, AppKit looks it up from jetton metadata (one extra read). Same rule as useBalance: don't pass the result through formatUnits again.
• useJettonInfo({ address, network? }) — address is the jetton master contract address. Returns { name, symbol, decimals?, image, … } | null.
• useJettonWalletAddress({ jettonAddress, ownerAddress, network? }) — resolves the owner's individual jetton-wallet contract address for a given jetton.
• useWatchJettons() / useWatchJettonsByAddress(...) — real-time jetton list updates (requires streaming provider).
• useWatchBalanceByAddress({ address, network? }) — real-time balance for an arbitrary address.
• useNfts() — returns { nfts: NFT[], addressBook? }. Use data?.nfts, not data directly.
• useNft({ address }) (address is the NFT item's own contract address — NOT tokenAddress)

Sending

useTransferTon() · useTransferJetton() · useTransferNft() · useSendTransaction()

Call with mutate({ recipientAddress, amount: '0.5', comment? }). Amount is a human-readable string — AppKit converts using token decimals. The mutation's data resolves to SendTransactionResponse = { boc, normalizedBoc, normalizedHash } (object, not a bare string).

Param names differ per asset — easy to get wrong from intuition:

• TON: mutate({ recipientAddress, amount, comment? })
• Jetton: mutate({ jettonAddress, recipientAddress, amount, comment? }) — jettonAddress is the jetton master contract.
• NFT: mutate({ nftAddress, recipientAddress, amount?, comment? }) — nftAddress (NOT tokenAddress!) is the individual NFT item's contract address (nft.address from useNfts()). Optional amount is the forward TON (gas/notification), defaults are sensible. There is no <SendNftButton /> drop-in — compose from the hook.

Signing

useSignText() · useSignBinary() · useSignCell()

Network

useNetwork() (selected wallet's network, undefined if not connected) · useDefaultNetwork() returns [defaultNetwork, setDefaultNetwork] · useNetworks() · useBlockNumber()

For mainnet/testnet apps, configure both networks and make reads explicit when the UI lets users choose a network:

const [network, setNetwork] = useDefaultNetwork();
const { data: balance } = useBalanceByAddress({ address, network });
<button => setNetwork(Network.mainnet())}>Mainnet</button>
<button => setNetwork(Network.testnet())}>Testnet</button>

DeFi

• Swap: useSwapQuote({ from, to, amount, slippageBps? }) · useBuildSwapTransaction() · useSwapProviders() · useSwapProvider()
• Staking: useStakingProviders() · useStakingQuote({ amount, direction }) · useBuildStakeTransaction() · useStakedBalance({ userAddress })

When you compose these into a custom UI (instead of <SwapWidget /> / <StakingWidget />), you own loading and error state for every step: useSwapQuote().isLoading for the quote, useBuildSwapTransaction().isPending for the build, useSendTransaction().isPending for the send. Disable the submit button on the active step's pending flag, render the active step's error.message, and call reset() for retry. The widgets handle this for you; the hooks deliberately don't.

Crypto Onramp (buy TON/jettons with crypto from another chain)

Onramp lets a user deposit crypto on a source chain (e.g. USDT on Arbitrum) and receive TON or a jetton. It needs a provider registered in AppKit config — same providers: [] array as swap/staking/streaming. The widget renders nothing useful until one is registered:

import { createLayerswapProvider } from '@ton/appkit/crypto-onramp/layerswap';
import { createDecentProvider } from '@ton/appkit/crypto-onramp/decent';

const appKit = new AppKit({
    networks: { /* ... */ },
    providers: [
        createLayerswapProvider(),                 // config optional
        createDecentProvider({ apiKey: 'KEY' }),   // apiKey required
    ],
});

Hooks (from @ton/appkit-react):

• useCryptoOnrampProviders() — all registered onramp providers (array). useCryptoOnrampProvider() returns [selected, setSelected] tuple.
• useCryptoOnrampProviderById({ id }) — one provider by id. Param is id.
• useCryptoOnrampProviderMetadata({ providerId }) — provider display metadata (name/logo/refundAddressMode). Synchronous (no query) and the param here is providerId, not id — the two onramp hooks disagree on the name, easy to get wrong.
• useCryptoOnrampSupportedCurrencies({ providerId? }) — { source[], destination[] } lists. Cached aggressively (1h stale).
• useCryptoOnrampQuote({ amount, sourceCurrency, targetCurrency, recipientAddress, isSourceAmount?, providerId? }) — query; returns a CryptoOnrampQuote with sourceAmount/targetAmount/rate in base units (not decimal strings — unlike useBalance).
• useCreateCryptoOnrampDeposit() — mutation; call mutateAsync({ quote, refundAddress }). Returns { depositId, address, amount, memo?, expiresAt? } — the address/memo the user must send funds to.
• useCryptoOnrampStatus({ depositId, providerId }) — poll status; 'pending' | 'success' | 'failed'. Auto-disabled until depositId is set.

Drop-in <CryptoOnrampWidget defaultDestination={{ address: 'ton' }} defaultSource={{ chain, address }} /> handles all of this. Use the hooks only for custom UX, and own loading/error per step like swap.

Custom providers

useCustomProvider<T>(id) retrieves an app-defined provider you registered yourself (providers: [myProvider], where myProvider.type === 'custom'). The argument is a positional string id, not an object — unlike every other hook here. Pass your provider's interface as the generic to narrow the return type:

const provider = useCustomProvider<MyProvider>('my-provider'); // MyProvider | undefined
if (!provider) return <p>Provider not registered</p>;

There is no runtime check that the registered provider matches T — the generic is a cast. You own ensuring the id maps to the shape you claim.

Drop-in Components

Full-featured React components from @ton/appkit-react. They handle their own state, loading, and errors:

Render-prop pattern for custom UI with built-in state:

<SwapWidget tokens={tokens}>{(ctx) => <YourUI {...ctx} />}</SwapWidget>

Query Key Prefixes

For invalidateQueries / removeQueries. TanStack prefix-matches on the first array element — passing queryKey: ['balance'] invalidates every ['balance', { address: A, network: M }], ['balance', { address: B, network: T }], etc. You rarely need to enumerate addresses; matching by the bare prefix is enough.

Four Critical Patterns

1. Real-time updates (streaming)

Streaming is opt-in. Two requirements: register a provider + mount the watch hook.

import { createTonCenterStreamingProvider } from '@ton/appkit';

const appKit = new AppKit({
    networks: { /* ... */ },
    providers: [
        createTonCenterStreamingProvider({ network: Network.mainnet(), apiKey: 'KEY' }),
    ],
});

function BalanceDisplay() {
    const { data: balance } = useBalance(); // already-formatted decimal string like "0.5"
    useWatchBalance(); // writes WS updates into useBalance cache
    return <p>{balance ?? '—'} TON</p>;
}

Without both, useBalance is one-shot.

Streaming-provider auth quirks (keyless != work):

• createTonCenterStreamingProvider({ network, apiKey }) — apiKey is optional; keyless works but is heavily rate-limited.
• createTonApiStreamingProvider({ network, apiKey }) — apiKey is effectively required. Keyless WebSocket connections to wss://tonapi.io/streaming/v2/ws are closed by the gateway with HTTP 401; the provider then reconnects in a loop and floods the console with WebSocket error lines. Get a token from https://tonconsole.com or fall back to createTonCenterStreamingProvider if you want a keyless option.

2. Cache after mutations

Mutations don't auto-invalidate. Use invalidateQueries after transfers and removeQueries after disconnect:

const queryClient = useQueryClient();

// After transfer: invalidate so the next render refetches
useTransferTon({
    mutation: { onSuccess: () => queryClient.invalidateQueries({ queryKey: ['balance'] }) },
});

// After disconnect: remove entirely so old wallet's data can't flash
useDisconnect({
    mutation: {
        onSuccess: () => {
            ['balance', 'nfts', 'nft', 'jettons', 'jetton-balance', 'jetton-info', 'jetton-wallet-address', 'stakedBalance'].forEach(key =>
                queryClient.removeQueries({ queryKey: [key] }),
            );
        },
    },
});

removeQueries is correct on disconnect because there's no wallet to refetch for — leaving stale entries would flash the old wallet's data before the new wallet loads.

For a stronger guarantee when wallet switches happen mid-flight (pending tx, hooks holding stale data), wrap wallet-scoped UI with key={address} so React remounts the whole subtree on address change:

const address = useAddress();
return <WalletScopedUI key={address ?? 'disconnected'} />;

This kills any in-flight mutation state, useState, and refs tied to the previous wallet — cleanest fix for "spinner stuck forever after switching wallets". Combine with removeQueries on disconnect for the cache layer.

3. Transaction confirmation is not instant

useTransferTon / useSendTransaction resolve when the wallet accepts the tx — not when it's confirmed on-chain. Balances won't reflect the change immediately even after onSuccess. data is SendTransactionResponse = { boc, normalizedBoc, normalizedHash } — an object, not a bare BOC string. Two patterns:

// (a) Drop-in: <TransactionProgress /> tracks the tx until finalized
const { mutate, data } = useTransferTon();
{data && <TransactionProgress boc={data.boc} => /* now confirmed */} />}

// (b) Hooks: invalidate on accept; the next refetch picks up the new state once on-chain
useTransferTon({
    mutation: { onSuccess: () => queryClient.invalidateQueries({ queryKey: ['balance'] }) },
});

To track a tx by hash (e.g. backend webhook lookup), use data.normalizedHash.

Pair with useWatchBalance() + streaming if you want the balance to refresh the instant confirmation lands without a manual refetch.

4. Transaction error handling

const { mutate, isPending, error, reset } = useTransferTon();
const isUserRejection = (err: Error) => /reject|cancel|abort/i.test(err.message);

<button disabled={isPending} => mutate(params)}>Send</button>
{error && (
    <>
        <p>{isUserRejection(error) ? 'Cancelled' : `Error: ${error.message}`}</p>
        <button again</button>
    </>
)}

Disable only on isPending, not isError (button must re-enable so user can retry). Use reset() for retry. For swap/staking, @ton/appkit exports DefiError (with DefiErrorCode) for typed handling.

No-wallet fallback

When the user has no TON wallet installed (no browser extension, no Tonkeeper on the device), <TonConnectButton /> still works — but the experience changes:

• On mobile without Tonkeeper installed, the universal link opens the App Store / Google Play install flow.
• On desktop without a browser-extension wallet, TonConnect opens a modal with QR codes — the user scans from their mobile wallet to connect. This is intentional and works without any code from you.

For a custom Connect button, you can detect emptiness via useConnectors() and render a fallback CTA:

const connectors = useConnectors();
if (connectors.length === 0) {
    return (
        <a href="https://tonkeeper.com/download" target="_blank" rel="noreferrer">
            Install Tonkeeper to continue
        </a>
    );
}

But for most apps the right answer is just use <TonConnectButton /> and rely on TonConnect's built-in universal/QR/install-redirect flow — it covers all three cases (extension, mobile-installed, mobile-not-installed → install link, desktop → QR) without you wiring it.

Common Gotchas

1. QueryClientProvider wraps AppKitProvider — not the other way around. AppKitProvider doesn't create its own QueryClient.
2. useBalance returns a pre-formatted TON decimal string (e.g. "0.500000000"), not raw nano and not bigint. Same for useJettons().data.jettons[i].balance (formatted using the jetton's own decimals). Render directly or format with Intl.NumberFormat; calling formatUnits(balance, 9) again will re-slice the string on the decimal point and produce "0..500000000".
3. Amounts are strings ('0.5', not 500000000n). AppKit applies token decimals internally.
4. Streaming is opt-in — needs both a provider in config and useWatchBalance mounted.
5. Network mismatch breaks transactions — if the connected wallet is on testnet but your defaultNetwork is mainnet (or vice versa), TonConnect rejects the tx and your useTransferTon mutation lands in error with a network-mismatch message. Set defaultNetwork, expose switching with useDefaultNetwork(), and pass network into address-based reads. Check before sending:

   const walletNetwork = useNetwork();
   const [defaultNetwork] = useDefaultNetwork();
   const networkMismatch = walletNetwork && walletNetwork.chainId !== defaultNetwork.chainId;
   

   Mainnet chainId -239, testnet -3.
6. iOS deep links need synchronous click — call connect() directly in the handler, no await before it (see Wallet section above for the anti-pattern).
7. Telegram Mini App return — configure tonConnectOptions.actionsConfiguration.returnStrategy.
8. React 19 / Next 15 hook errors — check @tonconnect/ui-react version + run pnpm why react for duplicates.
9. <StakingWidget /> + keyless TonCenter = HTTP 429 cascade — while the widget is mounted, its internal queries poll with refetchInterval: 5000 (three queries: provider info, staked/token balances, quote), and each refresh can hit several TonCenter endpoints (getPoolBalance / getPoolData / APY). The Tonstakers provider itself has NO internal timer — registering createTonstakersProvider() alone causes no traffic; it only adds a 30s-TTL cache around on-demand reads. With a keyless apiClient: { url: 'https://toncenter.com' }, the widget's polling quickly exhausts the IP's anonymous TonCenter quota and cascades HTTP 429s into otherwise-unrelated reads (useBalance, useJettons, useNfts). Symptom: balance/jettons/nfts hang or fail, staking widget itself stays empty. Fix: set a real TonCenter apiKey on the apiClient, or don't mount <StakingWidget /> until you have one.
10. <SwapWidget /> swallows build/send errors silently — its ctx.error carries only client-side validation messages. Failures from useBuildSwapTransaction (e.g. Omniston returning Internal server error: 5: [hash], an expired quote, no liquidity at execution time) and from useSendTransaction become unhandled promise rejections: the Continue button appears to do nothing, no toast, no in-widget error. Diagnose in DevTools Console (look for Unhandled rejection: SwapError: …). If you're composing your own UI via the render-prop, wrap ctx.sendSwapTransaction() in try/catch and surface the error yourself, or attach a window.addEventListener('unhandledrejection', ...) handler. For custom flows, the hooks (useSwapQuote → useBuildSwapTransaction → useSendTransaction) each expose their own error field — use them directly instead.