Developer Docs

Developer Guide: SDK Integration

A comprehensive guide for developers to integrate StableFlow’s cross-chain transfers into your applications.

Getting Started

Installation

npm install stableflow-ai-sdk

Prerequisites

Node.js: Version 16 or higher
JWT Token: Required for API access
TypeScript (recommended): For full type safety

API Configuration

Basic Setup

import { OpenAPI, SFA } from 'stableflow-ai-sdk';

// Configure API endpoint
OpenAPI.BASE = 'https://api.stableflow.ai';

// Set your JWT token
OpenAPI.TOKEN = 'your-jwt-token-here';

Configuration Options

Option

Type

Description

Required

OpenAPI.BASE

string

API endpoint URL

Yes

OpenAPI.TOKEN

string

JWT authentication token

Yes

OpenAPI.WITH_CREDENTIALS

boolean

Include credentials in requests

OpenAPI.HEADERS

object

Additional request headers

Core Functions

1. `getTokens()`

Retrieves the list of all supported tokens across different blockchains.

Signature

SFA.getTokens(): Promise<TokenResponse[]>

Returns

Array of TokenResponse objects containing:

interface TokenResponse {
  assetId: string;        // Unique asset identifier
  blockchain: string;     // Network ID (e.g., 'eth', 'arb', 'pol')
  symbol: string;         // Token symbol (e.g., 'USDT', 'USDC')
  decimals: number;       // Token decimals (e.g., 6, 18)
  address?: string;       // Contract address
  price?: string;         // Current price in USD
}

Example Usage

// Fetch all supported tokens
const tokens = await SFA.getTokens();

// Filter USDT tokens
const usdtTokens = tokens.filter(t => t.symbol === 'USDT');

// Get tokens for specific network
const ethTokens = tokens.filter(t => t.blockchain === 'eth');

// Find specific token
const arbUsdc = tokens.find(
  t => t.blockchain === 'arb' && t.symbol === 'USDC'
);

Use Cases

Building token selection UI
Validating supported tokens
Getting current token prices
Discovering available networks

2. `getQuote()`

Requests a quote for cross-chain token swap, including fees, estimated time, and deposit address.

Signature

SFA.getQuote(request: QuoteRequest): Promise<QuoteResponse>

Request Parameters

interface QuoteRequest {
  // Testing mode (true = no real deposit address)
  dry: boolean;
  
  // Swap calculation type
  swapType: 'EXACT_INPUT' | 'EXACT_OUTPUT';
  
  // Slippage tolerance in basis points (100 = 1%)
  slippageTolerance: number;
  
  // Source token asset ID
  originAsset: string;
  
  // Where user deposits funds
  depositType: 'ORIGIN_CHAIN' | 'NEAR';
  
  // Destination token asset ID
  destinationAsset: string;
  
  // Amount in token's smallest unit
  amount: string;
  
  // Refund address if swap fails
  refundTo: string;
  
  // Refund location
  refundType: 'ORIGIN_CHAIN' | 'NEAR';
  
  // Recipient address for destination tokens
  recipient: string;
  
  // Recipient location
  recipientType: 'DESTINATION_CHAIN' | 'NEAR';
  
  // Quote expiration time (ISO 8601)
  deadline: string;
  
  // Optional: max wait time for quote in milliseconds
  quoteWaitingTimeMs?: number;
}

Response

interface QuoteResponse {
  quote: {
    depositAddress: string;      // Address to send tokens to
    amountIn: string;             // Input amount (smallest unit)
    amountInFormatted: string;    // Input amount (human-readable)
    amountOut: string;            // Output amount (smallest unit)
    amountOutFormatted: string;   // Output amount (human-readable)
    minAmountOut: string;         // Minimum output after slippage
    amountInUsd: string;          // Input value in USD
    amountOutUsd: string;         // Output value in USD
    timeEstimate: number;         // Estimated completion time (seconds)
    appFee?: AppFee;              // Fee breakdown
  };
  swapDetails: SwapDetails;       // Detailed swap information
  transactionDetails: TransactionDetails;  // Transaction parameters
}

Example Usage

import { QuoteRequest } from 'stableflow-ai-sdk';

const quoteRequest: QuoteRequest = {
  dry: false,  // Get real deposit address
  swapType: QuoteRequest.swapType.EXACT_INPUT,
  slippageTolerance: 100,  // 1%
  
  // Swap from Arbitrum USDT to Ethereum USDT
  originAsset: 'nep141:arb-0xfd086bc7cd5c481dcc9c85ebe478a1c0b69fcbb9.omft.near',
  destinationAsset: 'nep141:eth-0xdac17f958d2ee523a2206206994597c13d831ec7.omft.near',
  
  amount: '1000000',  // 1 USDT (6 decimals)
  
  depositType: QuoteRequest.depositType.ORIGIN_CHAIN,
  refundTo: '0xYourArbitrumAddress',
  refundType: QuoteRequest.refundType.ORIGIN_CHAIN,
  
  recipient: '0xYourEthereumAddress',
  recipientType: QuoteRequest.recipientType.DESTINATION_CHAIN,
  
  deadline: new Date(Date.now() + 24 * 60 * 60 * 1000).toISOString(),
};

const quote = await SFA.getQuote(quoteRequest);

console.log('Deposit to:', quote.quote.depositAddress);
console.log('You will receive:', quote.quote.amountOutFormatted);
console.log('Estimated time:', quote.quote.timeEstimate, 'seconds');

Important Notes

dry: true: Testing mode, no real deposit address
dry: false: Production mode, returns real deposit address
Amount Format: Always use smallest token unit (e.g., 1 USDT = 1000000 for 6 decimals)
Deadline: Must be a future timestamp in ISO 8601 format
Address Validation: Ensure addresses match the respective network format

3. `submitDepositTx()`

Notifies StableFlow that you've sent tokens to the deposit address.

Signature

SFA.submitDepositTx(request: SubmitDepositTxRequest): Promise<SubmitDepositTxResponse>

Request Parameters

interface SubmitDepositTxRequest {
  txHash: string;           // Transaction hash from blockchain
  depositAddress: string;   // Deposit address from quote
}

Response

interface SubmitDepositTxResponse {
  success: boolean;
  message?: string;
}

Example Usage

// After sending tokens to deposit address
const txHash = '0x123...abc';  // From blockchain transaction
const depositAddress = quote.quote.depositAddress;

const result = await SFA.submitDepositTx({
  txHash,
  depositAddress,
});

if (result.success) {
  console.log('Transaction submitted successfully!');
}

When to Call

After sending tokens to depositAddress
After transaction is confirmed on blockchain
Before checking execution status

4. `getExecutionStatus()`

Checks the current status of a cross-chain swap.

Signature

SFA.getExecutionStatus(depositAddress: string): Promise<GetExecutionStatusResponse>

Parameters

Parameter

Type

Description

depositAddress

string

Deposit address from quote

Response

interface GetExecutionStatusResponse {
  status: 'pending' | 'processing' | 'completed' | 'failed';
  depositTxHash?: string;
  destinationTxHash?: string;
  message?: string;
  updatedAt: string;
}

Example Usage

const status = await SFA.getExecutionStatus(depositAddress);

switch (status.status) {
  case 'pending':
    console.log('Waiting for deposit confirmation...');
    break;
  case 'processing':
    console.log('Swap in progress...');
    break;
  case 'completed':
    console.log('Swap completed!');
    console.log('Destination tx:', status.destinationTxHash);
    break;
  case 'failed':
    console.log('Swap failed:', status.message);
    break;
}

Polling Example

async function waitForCompletion(depositAddress: string) {
  const maxAttempts = 60;  // 5 minutes with 5s interval
  
  for (let i = 0; i < maxAttempts; i++) {
    const status = await SFA.getExecutionStatus(depositAddress);
    
    if (status.status === 'completed') {
      return status;
    }
    
    if (status.status === 'failed') {
      throw new Error(status.message);
    }
    
    // Wait 5 seconds before next check
    await new Promise(resolve => setTimeout(resolve, 5000));
  }
  
  throw new Error('Timeout waiting for swap completion');
}

Working Examples

The SDK includes a complete web application example demonstrating real-world usage.

Web Demo Application

Location: examples/web-demo/

Features

â Real wallet connection (MetaMask)
â Network switching
â Token balance checking
â Quote generation
â Transaction execution
â Status tracking

Running the Example

cd examples/web-demo
npm install
npm run dev

Key Files to Study

app.ts - Main application logic
- Wallet connection: connectWallet()
- Network switching: switchNetwork()
- Getting quotes: handleGetQuote()
- Executing swaps: executeBridge()

Network Configuration

const SUPPORTED_NETWORKS = [
  {
    id: 'eth',
    name: 'Ethereum',
    chainId: 1,
    usdtContract: '0xdac17f958d2ee523a2206206994597c13d831ec7',
    usdtAssetId: 'nep141:eth-0xdac17f958d2ee523a2206206994597c13d831ec7.omft.near',
    decimals: 6
  },
  // ... more networks
];

ERC20 Token Transfer

// Create contract instance
const erc20Abi = ['function transfer(address to, uint256 amount) returns (bool)'];
const usdtContract = new ethers.Contract(
  fromNetwork.usdtContract,
  erc20Abi,
  signer
);

// Execute transfer
const tx = await usdtContract.transfer(depositAddress, amount);
await tx.wait();

Learning Path

Start with: Understanding the flow in app.ts
Study: Network configuration and asset IDs
Review: Error handling patterns
Examine: UI/UX best practices
Customize: Adapt for your use case

Best Practices

1. Error Handling

Always wrap SDK calls in try-catch blocks:

import { ApiError } from 'stableflow-ai-sdk';

try {
  const quote = await SFA.getQuote(request);
} catch (error) {
  if (error instanceof ApiError) {
    switch (error.status) {
      case 400:
        // Invalid request parameters
        console.error('Bad request:', error.body);
        break;
      case 401:
        // Authentication failed
        console.error('Invalid JWT token');
        break;
      case 404:
        // Resource not found
        console.error('Endpoint not found');
        break;
      default:
        console.error('API error:', error.message);
    }
  } else {
    // Network or other errors
    console.error('Unexpected error:', error);
  }
}

2. Token Amount Conversion

Always convert human-readable amounts to smallest units:

import { ethers } from 'ethers';

// Human-readable to smallest unit
const decimals = 6;  // USDT decimals
const humanAmount = '100.5';  // 100.5 USDT
const smallestUnit = ethers.parseUnits(humanAmount, decimals);
// Result: 100500000n

// Smallest unit to human-readable
const formatted = ethers.formatUnits(smallestUnit, decimals);
// Result: '100.5'

3. Deadline Management

Set reasonable deadlines:

// Good: 24 hours from now
const deadline = new Date(Date.now() + 24 * 60 * 60 * 1000).toISOString();

// Bad: Past timestamp
const badDeadline = new Date('2020-01-01').toISOString();  // â

// Bad: Too short
const tooShort = new Date(Date.now() + 60 * 1000).toISOString();  // â

4. Network Validation

Validate network compatibility:

async function validateNetworks(fromNetwork: string, toNetwork: string) {
  if (fromNetwork === toNetwork) {
    throw new Error('Source and destination networks must be different');
  }
  
  const tokens = await SFA.getTokens();
  const fromTokens = tokens.filter(t => t.blockchain === fromNetwork);
  const toTokens = tokens.filter(t => t.blockchain === toNetwork);
  
  if (fromTokens.length === 0) {
    throw new Error(`Network ${fromNetwork} not supported`);
  }
  
  if (toTokens.length === 0) {
    throw new Error(`Network ${toNetwork} not supported`);
  }
}

5. Status Polling

Implement exponential backoff:

async function pollStatus(depositAddress: string) {
  let delay = 2000;  // Start with 2 seconds
  const maxDelay = 30000;  // Max 30 seconds
  const maxAttempts = 100;
  
  for (let i = 0; i < maxAttempts; i++) {
    const status = await SFA.getExecutionStatus(depositAddress);
    
    if (status.status === 'completed' || status.status === 'failed') {
      return status;
    }
    
    await new Promise(resolve => setTimeout(resolve, delay));
    
    // Exponential backoff
    delay = Math.min(delay * 1.5, maxDelay);
  }
  
  throw new Error('Polling timeout');
}

Common Use Cases

Use Case 1: Simple USDT Bridge

Bridge USDT from Ethereum to Arbitrum:

// 1. Get tokens to find asset IDs
const tokens = await SFA.getTokens();
const ethUsdt = tokens.find(t => t.blockchain === 'eth' && t.symbol === 'USDT');
const arbUsdt = tokens.find(t => t.blockchain === 'arb' && t.symbol === 'USDT');

// 2. Create quote request
const quoteRequest: QuoteRequest = {
  dry: false,
  swapType: QuoteRequest.swapType.EXACT_INPUT,
  slippageTolerance: 100,
  originAsset: ethUsdt.assetId,
  destinationAsset: arbUsdt.assetId,
  amount: ethers.parseUnits('100', 6).toString(),  // 100 USDT
  depositType: QuoteRequest.depositType.ORIGIN_CHAIN,
  refundTo: userEthAddress,
  refundType: QuoteRequest.refundType.ORIGIN_CHAIN,
  recipient: userArbAddress,
  recipientType: QuoteRequest.recipientType.DESTINATION_CHAIN,
  deadline: new Date(Date.now() + 24 * 60 * 60 * 1000).toISOString(),
};

// 3. Get quote
const quote = await SFA.getQuote(quoteRequest);

// 4. Transfer USDT to deposit address
const usdtContract = new ethers.Contract(
  '0xdac17f958d2ee523a2206206994597c13d831ec7',
  ['function transfer(address to, uint256 amount) returns (bool)'],
  signer
);
const tx = await usdtContract.transfer(
  quote.quote.depositAddress,
  ethers.parseUnits('100', 6)
);
await tx.wait();

// 5. Submit transaction
await SFA.submitDepositTx({
  txHash: tx.hash,
  depositAddress: quote.quote.depositAddress,
});

// 6. Monitor status
const finalStatus = await pollStatus(quote.quote.depositAddress);
console.log('Bridge completed!', finalStatus.destinationTxHash);

Use Case 2: Dynamic Token Selection

Let users choose any supported token pair:

async function buildTokenPairSelector() {
  const tokens = await SFA.getTokens();
  
  // Group by network
  const byNetwork = tokens.reduce((acc, token) => {
    if (!acc[token.blockchain]) {
      acc[token.blockchain] = [];
    }
    acc[token.blockchain].push(token);
    return acc;
  }, {} as Record<string, TokenResponse[]>);
  
  // Build UI options
  const networks = Object.keys(byNetwork);
  
  return {
    networks,
    getTokensForNetwork: (network: string) => byNetwork[network],
    findToken: (network: string, symbol: string) =>
      byNetwork[network]?.find(t => t.symbol === symbol),
  };
}

Use Case 3: Fee Calculator

Calculate bridge fees before execution:

async function calculateFees(
  fromToken: TokenResponse,
  toToken: TokenResponse,
  amount: string
) {
  const quoteRequest: QuoteRequest = {
    dry: true,  // Testing mode
    swapType: QuoteRequest.swapType.EXACT_INPUT,
    slippageTolerance: 100,
    originAsset: fromToken.assetId,
    destinationAsset: toToken.assetId,
    amount,
    // ... other required fields
  };
  
  const quote = await SFA.getQuote(quoteRequest);
  
  const feeUsd = parseFloat(quote.quote.amountInUsd) - 
                 parseFloat(quote.quote.amountOutUsd);
  const feePercent = (feeUsd / parseFloat(quote.quote.amountInUsd)) * 100;
  
  return {
    feeUsd: feeUsd.toFixed(4),
    feePercent: feePercent.toFixed(2),
    estimatedTime: quote.quote.timeEstimate,
    minimumReceived: quote.quote.amountOutFormatted,
  };
}

Troubleshooting

Common Issues

1. "Invalid token" Error

Cause: Using incorrect assetId format

Solution: Always get asset IDs from getTokens():

const tokens = await SFA.getTokens();
const token = tokens.find(t => 
  t.blockchain === 'eth' && t.symbol === 'USDT'
);
// Use: token.assetId

2. "Deadline is not valid" Error

Cause: Deadline is in the past or incorrect format

Solution: Use ISO 8601 format with future timestamp:

const deadline = new Date(Date.now() + 24 * 60 * 60 * 1000).toISOString();

3. Authentication Errors

Cause: Missing or invalid JWT token

Solution:

ð Apply for JWT Token Here

After receiving your token, set it before any API calls:

OpenAPI.TOKEN = 'your-valid-token';

4. Network Mismatch

Cause: Wallet on wrong network when sending transaction

Solution: Check and switch network before transaction:

const currentChainId = await window.ethereum.request({ 
  method: 'eth_chainId' 
});

if (currentChainId !== expectedChainId) {
  await window.ethereum.request({
    method: 'wallet_switchEthereumChain',
    params: [{ chainId: expectedChainId }],
  });
}

5. Transaction Stuck

Cause: Transaction not confirmed on blockchain

Solution: Wait for confirmation before submitting:

const tx = await usdtContract.transfer(depositAddress, amount);
const receipt = await tx.wait();  // Wait for confirmation
console.log('Confirmed in block:', receipt.blockNumber);

// Now submit to StableFlow
await SFA.submitDepositTx({ txHash: tx.hash, depositAddress });

Additional Resources

SDK Repository

GitHub: stableflow-ai/stableflow-ai-sdk
Examples: examples/ directory
Issues: Report bugs via GitHub Issues

StableFlow Platform

Website: https://app.stableflow.ai/
API Access: Apply for JWT token
Documentation: Latest API specs

Community

Discord: Join our community
Twitter: @StableFlowAI

Summary

Quick Reference

Function

Purpose

Required Fields

getTokens()

List supported tokens

JWT Token

getQuote()

Get swap quote

JWT Token, QuoteRequest

submitDepositTx()

Notify deposit

JWT Token, txHash, depositAddress

getExecutionStatus()

Check swap status

JWT Token, depositAddress

Integration Checklist

Happy Building!

For questions or support, visit our GitHub repository or join our Discord community.

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Table of Contents

Getting Started

Installation

Prerequisites

API Configuration

Basic Setup

Configuration Options

Core Functions

1. getTokens()

2. getQuote()

3. submitDepositTx()

4. getExecutionStatus()

Working Examples

Web Demo Application

Best Practices

1. Error Handling

2. Token Amount Conversion

3. Deadline Management

4. Network Validation

5. Status Polling

Common Use Cases

Use Case 1: Simple USDT Bridge

Use Case 2: Dynamic Token Selection

Use Case 3: Fee Calculator

Troubleshooting

Common Issues

Additional Resources

SDK Repository

StableFlow Platform

Community

Summary

Quick Reference

Integration Checklist

Happy Building!

1. `getTokens()`

2. `getQuote()`

3. `submitDepositTx()`

4. `getExecutionStatus()`