Liquidity Providing Guide

This guide will walk you through creating a basic liquidity provision app using the STON.fi SDK and API in a React project. We'll integrate wallet connectivity with TonConnect (via @tonconnect/ui-react) to allow users to connect their TON wallet and provide liquidity to pools. The guide is beginner-friendly and assumes minimal React experience.

Note: In this demo, we will leverage Tailwind CSS for styling instead of using custom CSS. The setup for Tailwind CSS is already included in the instructions below, so you don't need to set it up separately.

Note: You can use any package manager (npm, yarn, pnpm, or bun) to set up your React project. In this tutorial, we'll demonstrate with pnpm.

---

Table of Contents

1. Introduction

2. Setting Up the Project

   1. Create a React App

   2. Installing the Required Packages

3. Connecting the Wallet

   1. Add the TonConnect Provider

   2. Create the TonConnect Manifest

   3. Add the Connect Wallet Button

4. Fetching Available Assets

5. Simulating Liquidity Provision

   1. Handling "Pool Already Exists"

6. Building the Transaction

7. Executing the Provision

8. Testing Your Provision

9. Conclusion

10. Live Demo

11. Next steps

---

1. Introduction

In this quickstart, we will build a minimal React app to:

• Connect to a TON wallet (via TonConnect UI).

• Fetch available tokens from STON.fi (via @ston-fi/api).

• Simulate liquidity provision (to see expected LP tokens).

• Execute a liquidity provision transaction on-chain (via @ston-fi/sdk).

We will use:

• @ston-fi/sdk – Helps build the payload for the actual liquidity provision transaction.

• @ston-fi/api – Lets us fetch asset lists and run liquidity provision simulations.

• @tonconnect/ui-react – Provides a React-based TON wallet connect button and utilities.

---

2. Setting Up the Project

2.1 Create a React App

First, check if you have pnpm installed:

pnpm --version

If pnpm is not installed, install it globally:

npm install -g pnpm

Create a new React + Vite project:

pnpm create vite --template react-ts

Provide a project name (e.g., stonfi-liquidity-app) and then:

cd stonfi-liquidity-app

2.2 Installing the Required Packages

In your project directory, install the required packages:

pnpm add @ston-fi/sdk @ston-fi/api @tonconnect/ui-react @ton/ton

Install Tailwind CSS and the Node.js polyfills plugin for Vite:

pnpm add tailwindcss @tailwindcss/vite vite-plugin-node-polyfills

Configure Vite by updating vite.config.js:

import { defineConfig } from "vite";
import react from "@vitejs/plugin-react";
import tailwindcss from "@tailwindcss/vite";
import { nodePolyfills } from "vite-plugin-node-polyfills";

export default defineConfig({
  plugins: [react(), tailwindcss(), nodePolyfills()],
});

In src/index.css, import Tailwind:

@import "tailwindcss";

You can also remove src/App.css (we don't need it), and remove the import statement import './App.css' from src/App.tsx.

After making these changes, you can verify that your app still runs correctly by starting the development server:

pnpm install
pnpm dev

Open http://localhost:5173. If you see a Vite/React starter page, everything is working correctly.

---

3. Connecting the Wallet

3.1 Add the TonConnect Provider

Open src/main.tsx and wrap your app in TonConnectUIProvider:

import React from "react";
import ReactDOM from "react-dom/client";
import { TonConnectUIProvider } from "@tonconnect/ui-react";
import "./index.css";
import App from "./App.tsx";

ReactDOM.createRoot(document.getElementById("root")!).render(
  <React.StrictMode>
    <TonConnectUIProvider 
    // For demo purposes, we're using a static manifest URL
    // Replace with your own: manifestUrl={`${window.location.origin}/tonconnect-manifest.json`}
    manifestUrl="https://gist.githubusercontent.com/mrruby/243180339f492a052aefc7a666cb14ee/raw/"
    >

      <App />
    </TonConnectUIProvider>
  </React.StrictMode>
);

Note: For the purposes of this demo, we're serving the manifest from a static source. In a real application, you should replace this with your own manifest URL that you'll create in the next step.

3.2 Create the TonConnect Manifest

Create a file named tonconnect-manifest.json in your public folder:

{
    "url": "https://stonfi-liquidity-demo.example.com",
    "name": "STON.fi Liquidity Provider",
    "iconUrl": "https://stonfi-liquidity-demo.example.com/icon-192x192.png"
}

Update with your own app name, domain, and icon.

3.3 Add the Connect Wallet Button

In src/App.tsx, import and add the TonConnectButton:

import { TonConnectButton } from "@tonconnect/ui-react";

function App() {
  return (
    <div className="flex flex-col items-center justify-center min-h-screen p-6">
      <h1 className="text-2xl font-bold mb-4">STON.fi Liquidity Demo</h1>
      <TonConnectButton />
    </div>
  );
}

export default App;

---

4. Fetching Available Assets

Let's fetch token data from STON.fi using StonApiClient. We'll filter by liquidity tags to keep the list manageable.

First, add new imports to the top of src/App.tsx:

import { useEffect, useState } from "react";
import { TonConnectButton } from "@tonconnect/ui-react";
import { StonApiClient, AssetTag, type AssetInfoV2  } from "@ston-fi/api";

Initialize the STON.fi API client:

const stonApiClient = new StonApiClient();

Add state variables for token management:

function App() {
  const [tokens, setTokens] = useState<AssetInfoV2[]>([]);
  const [tokenA, setTokenA] = useState<AssetInfoV2 | undefined>();
  const [tokenB, setTokenB] = useState<AssetInfoV2 | undefined>();
  const [amountA, setAmountA] = useState("");
  const [amountB, setAmountB] = useState("");

Add the token fetching logic:

  // Fetch assets at startup
  useEffect(() => {
    const fetchTokens = async () => {
      try {
        const assets = await stonApiClient.queryAssets({
          // Query only assets with medium or higher liquidity to ensure tradability
          condition: `${AssetTag.LiquidityVeryHigh} | ${AssetTag.LiquidityHigh} | ${AssetTag.LiquidityMedium}`,
        });

        setTokens(assets);

        // Initialize default selections
        setTokenA(assets[0]);
        setTokenB(assets[1]);
      } catch (err) {
        console.error("Failed to fetch tokens:", err);
      }
    };
    fetchTokens();
  }, []);

Add the token change handler:

  // Factory function for creating onChange handlers for token dropdowns
  // Uses composition to create reusable handlers for both token selectors
  const handleTokenChange =
    (setter: typeof setTokenA | typeof setTokenB) =>
    (event: { target: { value: string } }) => {
      const selected = tokens.find(
        (t) => t.contractAddress === event.target.value
      );
      if (selected) {
        setter(selected);
      }
    };

Replace the return statement with the enhanced UI:

  return (
    <div className="flex flex-col items-center justify-center min-h-screen bg-gradient-to-b from-blue-50 to-indigo-100 p-6">
      <div className="max-w-md w-full bg-white rounded-lg shadow p-6 space-y-6">
        {/* Application header with branding and wallet connection */}
        <div className="flex justify-between items-center">
          <h1 className="text-2xl font-bold text-indigo-700">
            STON.fi Liquidity
          </h1>
          <TonConnectButton />
        </div>
        <hr className="border-gray-200" />

        {/* Main application interface (conditional on token data availability) */}
        {tokens.length > 0 ? (
          <>
            {/* Token A selection dropdown */}
            <div>
              <label className="block mb-1 text-sm font-medium text-gray-600">
                Token A
              </label>
              <select
                className="w-full p-2 border rounded"
                onChange={handleTokenChange(setTokenA)}
                value={tokenA?.contractAddress || ""}
              >
                {tokens.map((tok) => (
                  <option key={tok.contractAddress} value={tok.contractAddress}>
                    {tok.meta?.symbol ?? "Token"}
                  </option>
                ))}
              </select>
            </div>

            {/* Token B selection dropdown */}
            <div>
              <label className="block mb-1 text-sm font-medium text-gray-600">
                Token B
              </label>
              <select
                className="w-full p-2 border rounded"
                onChange={handleTokenChange(setTokenB)}
                value={tokenB?.contractAddress || ""}
              >
                {tokens.map((token) => (
                  <option
                    key={token.contractAddress}
                    value={token.contractAddress}
                  >
                    {token.meta?.symbol ?? "Token"}
                  </option>
                ))}
              </select>
            </div>

            {/* Amount input fields (side by side layout) */}
            <div className="flex space-x-4">
              <div className="flex-1">
                <label className="block mb-1 text-sm font-medium text-gray-600">
                  Amount A
                </label>
                <input
                  type="number"
                  className="w-full p-2 border rounded"
                  placeholder="0.0"
                  value={amountA}
                  onChange={(e) => setAmountA(e.target.value)}
                />
              </div>
              <div className="flex-1">
                <label className="block mb-1 text-sm font-medium text-gray-600">
                  Amount B
                </label>
                <input
                  type="number"
                  className="w-full p-2 border rounded"
                  placeholder="0.0"
                  value={amountB}
                  onChange={(e) => setAmountB(e.target.value)}
                />
              </div>
            </div>
          </>
        ) : (
          <p>Loading tokens...</p>
        )}
      </div>
    </div>
  );
}

---

5. Simulating Liquidity Provision

We'll call the simulateLiquidityProvision function on the StonApiClient to get simulation results.

Add additional imports to the top of the file:

import { useTonAddress } from "@tonconnect/ui-react";
import { type LiquidityProvisionSimulation } from "@ston-fi/api";
import { fromNano } from "@ton/ton";

Add utility functions for converting token amounts:

// Convert floating point string amount into integer base units string
// Essential for blockchain transactions which use integer arithmetic
function toBaseUnits(amount: string, decimals?: number) {
  return Math.floor(parseFloat(amount) * 10 ** (decimals ?? 9)).toString();
}

// Convert integer base units back to a fixed 2-decimal string for display
function fromBaseUnits(baseUnits: string, decimals?: number) {
  return (parseInt(baseUnits) / 10 ** (decimals ?? 9)).toFixed(2);
}

Add wallet address and simulation state:

function App() {
  const walletAddress = useTonAddress();
  
  // ... existing state variables ...
  
  const [simulation, setSimulation] = useState<
    LiquidityProvisionSimulation | Error | undefined
  >();

Add useEffect to reset simulation when tokens change:

  // Reset simulation when tokens change
  useEffect(() => {
    setSimulation(undefined);
  }, [tokenA, tokenB]);

Add the simulation handler after the existing handleTokenChange function:

  const handleSimulationClick = async () => {
    if (!tokenA || !tokenB || !amountA || !amountB) {
      alert("Please select tokens and enter amounts");
      return;
    }

    try {
      // Retrieve available pools for tokens pair
      const pools = (
        await stonApiClient.getPoolsByAssetPair({
          asset0Address: tokenA.contractAddress,
          asset1Address: tokenB.contractAddress,
        })
      ).filter((pool) => !pool.deprecated);

      const pool = pools[0];

      if (!pool) {
        throw new Error(
          `Pools for ${tokenA.meta?.symbol} ${tokenB.meta?.symbol} tokens not found`
        );
      }

      // Retrieve simulation
      const simulation = await stonApiClient.simulateLiquidityProvision({
        provisionType: "Balanced",
        tokenA: tokenA.contractAddress,
        tokenB: tokenB.contractAddress,
        tokenAUnits: toBaseUnits(amountA, tokenA?.meta?.decimals),
        poolAddress: pool.address,
        slippageTolerance: "0.001",
        walletAddress,
      });

      setSimulation(simulation);
      setAmountB(fromBaseUnits(simulation.tokenBUnits, tokenB?.meta?.decimals));
    } catch (e) {
      setSimulation(new Error(e instanceof Error ? e.message : String(e)));
    }
  };

Add the simulation button after the amount input fields:

            <div className="flex space-x-4">
              <div className="flex-1">
                <label className="block mb-1 text-sm font-medium text-gray-600">
                  Amount A
                </label>
                <input
                  type="number"
                  className="w-full p-2 border rounded"
                  placeholder="0.0"
                  value={amountA}
                  onChange={(e) => setAmountA(e.target.value)}
                />
              </div>
              <div className="flex-1">
                <label className="block mb-1 text-sm font-medium text-gray-600">
                  Amount B
                </label>
                <input
                  type="number"
                  className="w-full p-2 border rounded"
                  placeholder="0.0"
                  value={amountB}
                  onChange={(e) => setAmountB(e.target.value)}
                />
              </div>
            </div>

            {/* Simulation trigger button with validation */}
            <button
              onClick={handleSimulationClick}
              className="w-full bg-indigo-500 hover:bg-indigo-600 text-white font-medium py-2 rounded"
            >
              Simulate
            </button>

Add the simulation results display after the simulate button:

            {simulation ? (
              simulation instanceof Error ? (
                <p className="text-red-600 text-sm">{simulation.message}</p>
              ) : (
                <>
                  <div className="p-4 bg-gray-50 rounded border border-gray-200 text-sm overflow-x-auto break-all max-w-full">
                    <p className="font-semibold text-gray-800">
                      Simulation Result
                    </p>
                    <ul className="list-disc list-inside mt-2 space-y-1 text-gray-700">
                      {Object.entries({
                        "Provision Type": simulation.provisionType,
                        "Pool Address": simulation.poolAddress,
                        "Router Address": simulation.routerAddress,
                        "Token A": simulation.tokenA,
                        "Token B": simulation.tokenB,
                        "Token A Units": fromBaseUnits(
                          simulation.tokenAUnits,
                          tokenA?.meta?.decimals
                        ),
                        "Token B Units": fromBaseUnits(
                          simulation.tokenBUnits,
                          tokenB?.meta?.decimals
                        ),
                        "LP Account": simulation.lpAccountAddress,
                        "Estimated LP": fromNano(simulation.estimatedLpUnits),
                        "Min LP": fromNano(simulation.minLpUnits),
                        "Price Impact": simulation.priceImpact,
                      }).map(([label, value]) => (
                        <li key={label}>
                          <span className="font-medium">{label}:</span>{" "}
                          <span className="break-all">{value}</span>
                        </li>
                      ))}
                    </ul>
                  </div>
                </>
              )
            ) : null}

---

6. Building the Transaction

Go to TON Center and get your API key.

Then create a .env file in the root of your project and add your API key there:

VITE_TON_API_KEY=your_api_key_here

Now let's build the transaction using @ston-fi/sdk:

Add new imports to top of file and initialize TON JSON-RPC client:

import { useTonConnectUI } from "@tonconnect/ui-react";
import { dexFactory } from "@ston-fi/sdk";
import { TonClient, fromNano } from "@ton/ton";

// TON JSON-RPC client for blockchain interactions
const tonApiClient = new TonClient({
  endpoint: "https://toncenter.com/api/v2/jsonRPC",
  apiKey: import.meta.env.VITE_TON_API_KEY,
});

Add handleProvideLiquidityClick callback after handleSimulationClick callback:

const [tonConnectUI] = useTonConnectUI();

const handleProvideLiquidityClick = async () => {
  if (!simulation || simulation instanceof Error) {
    alert("Simulation is not valid");
    return;
  }

  const tonAsset = tokens.find((token) => token.kind === "Ton");
  if (!tonAsset) {
    alert("TON asset info not found");
    return;
  }

  try {
    // Retrieve router metadata
    const routerMetadata = await stonApiClient.getRouter(
      simulation.routerAddress
    );

    // Create contract instances
    const { Router, pTON } = dexFactory(routerMetadata);
    const router = tonApiClient.open(Router.create(routerMetadata.address));
    const pTon = pTON.create(routerMetadata.ptonMasterAddress);

    const isTonAsset = (contractAddress: string) =>
      contractAddress === tonAsset.contractAddress;

    const buildTransaction = async (args: {
      sendAmount: string;
      sendTokenAddress: string;
      otherTokenAddress: string;
    }) => {
      const params = {
        userWalletAddress: walletAddress,
        minLpOut: simulation.minLpUnits,
        sendAmount: args.sendAmount,
        otherTokenAddress: isTonAsset(args.otherTokenAddress)
          ? pTon.address
          : args.otherTokenAddress,
      };

      // TON requires proxy contract, Jettons use direct transfer
      if (isTonAsset(args.sendTokenAddress)) {
        return await router.getProvideLiquidityTonTxParams({
          ...params,
          proxyTon: pTon,
        });
      } else {
        return await router.getProvideLiquidityJettonTxParams({
          ...params,
          sendTokenAddress: args.sendTokenAddress,
        });
      }
    };

    // Generate transaction parameters for both tokens
    // Different methods are used for TON vs Jetton tokens due to blockchain mechanics
    const txParams = await Promise.all([
      buildTransaction({
        sendAmount: simulation.tokenAUnits,
        sendTokenAddress: simulation.tokenA,
        otherTokenAddress: simulation.tokenB,
      }),
      buildTransaction({
        sendAmount: simulation.tokenBUnits,
        sendTokenAddress: simulation.tokenB,
        otherTokenAddress: simulation.tokenA,
      }),
    ]);

    // Format transaction messages for TonConnect sendTransaction interface
    const messages = txParams.map((txParam) => ({
      address: txParam.to.toString(),
      amount: txParam.value.toString(),
      payload: txParam.body?.toBoc().toString("base64"),
    }));

    // Trigger TonConnect modal for user transaction approval
    await tonConnectUI.sendTransaction({
      validUntil: Date.now() + 5 * 60 * 1000, // Transaction valid for 5 minutes
      messages,
    });
  } catch (e) {
    alert(`Error: ${e}`);
  }
};

Add Provide Liquidity button after the simulation results div:

                    {Object.entries({
                      "Provision Type": simulation.provisionType,
                      "Pool Address": simulation.poolAddress,
                      "Router Address": simulation.routerAddress,
                      "Token A": simulation.tokenA,
                      "Token B": simulation.tokenB,
                      "Token A Units": fromBaseUnits(
                        simulation.tokenAUnits,
                        tokenA?.meta?.decimals
                      ),
                      "Token B Units": fromBaseUnits(
                        simulation.tokenBUnits,
                        tokenB?.meta?.decimals
                      ),
                      "LP Account": simulation.lpAccountAddress,
                      "Estimated LP": fromNano(simulation.estimatedLpUnits),
                      "Min LP": fromNano(simulation.minLpUnits),
                      "Price Impact": simulation.priceImpact,
                    }).map(([label, value]) => (
                      <li key={label}>
                        <span className="font-medium">{label}:</span>{" "}
                        <span className="break-all">{value}</span>
                      </li>
                    ))}
                  </ul>
                </div>

                <button
                  onClick={handleProvideLiquidityClick}
                  className="w-full bg-green-500 hover:bg-green-600 text-white font-medium py-2 rounded mt-4"
                >
                  Provide Liquidity
                </button>
                </>

              )
            ) : null}

---

7. Executing the Provision

After clicking "Provide Liquidity", your wallet will prompt you to confirm and sign. The transaction will:

1. Send token A and token B to the router contract

2. Add liquidity to the pool

3. Mint LP tokens to your LP wallet

---

8. Testing Your Provision

1. Start the dev server:

pnpm dev

1. Open http://localhost:5173

2. Connect your TON wallet

3. Select two tokens and enter amounts

4. Simulate to see expected LP tokens

5. Click "Provide Liquidity" to execute the transaction

6. Check your wallet for the new LP tokens

---

9. Conclusion

You've built a minimal React app that:

• Connects to a TON wallet

• Fetches tokens from STON.fi

• Simulates liquidity provision

• Handles both new and existing pools

• Executes the provision transaction

---

10. Live Demo

With this Replit demo, you can:

• Open the project directly in your browser

• Fork the Replit to make your own copy

• Run the application to see it in action

• Explore and modify the code to learn how it works

• Experiment with different features and UI changes

Alternatively, you can run this example locally by cloning the GitHub repository:

git clone https://github.com/mrruby/stonfi-liquidity-app.git
cd omniston-swap-app
pnpm install
pnpm dev

This will start the development server and you can access the app at http://localhost:5173.

Also remeber to add your TON API key to the .env file from Building the Transaction step.

---

10. Next steps

For more advanced features you can add:

• Dynamic slippage controls

• Burn liquidity read about it in the SDK docs
• See the SDK Liquidity docs for more details