Free Crypto Wallet API — Multi-Chain HD Wallets via REST

Need to create crypto wallets, check balances, or send transactions from your app? The Frostbyte Wallet API gives you programmatic access to HD wallet creation across 9 blockchains, balance queries, transaction sending, and cross-chain token swaps — all through a REST interface.

Whether you’re building a DeFi aggregator, an AI agent with a crypto wallet, a portfolio tracker, or a payment system, this API handles the wallet infrastructure so you don’t have to run nodes or manage private keys yourself.

Quick Start — Create a Wallet

# Create a new HD wallet
curl -X POST "https://agent-gateway-kappa.vercel.app/v1/frostbyte-wallet/v1/wallet/create" \
  -H "x-api-key: YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{"chain": "ethereum"}'

{
  "walletId": "wal_7f3a9b2c",
  "chain": "ethereum",
  "address": "0x742d35Cc6634C0532925a3b844Bc9e7595f2bD08",
  "publicKey": "0x04a1b2c3...",
  "mnemonic": "abandon ability able about above absent ...",
  "derivationPath": "m/44'/60'/0'/0/0",
  "createdAt": "2026-03-04T12:00:00Z"
}

import requests

BASE = "https://agent-gateway-kappa.vercel.app/v1/frostbyte-wallet"
headers = {
    "x-api-key": "YOUR_KEY",
    "Content-Type": "application/json"
}

# Create wallet on Ethereum
resp = requests.post(
    f"{BASE}/v1/wallet/create",
    headers=headers,
    json={"chain": "ethereum"}
)

wallet = resp.json()
print(f"Address: {wallet['address']}")
print(f"Chain: {wallet['chain']}")

# IMPORTANT: Store the mnemonic securely!
print(f"Mnemonic: {wallet['mnemonic']}")

const BASE = "https://agent-gateway-kappa.vercel.app/v1/frostbyte-wallet";
const headers = {
  "x-api-key": "YOUR_KEY",
  "Content-Type": "application/json"
};

// Create wallet on Polygon
const resp = await fetch(`${BASE}/v1/wallet/create`, {
  method: "POST",
  headers,
  body: JSON.stringify({ chain: "polygon" })
});
const wallet = await resp.json();

console.log("Address:", wallet.address);
console.log("Chain:", wallet.chain);

API Endpoints

All endpoints are accessed via the gateway at https://agent-gateway-kappa.vercel.app/v1/frostbyte-wallet.

Check Wallet Balance

# Get balance for any address
curl -H "x-api-key: YOUR_KEY" \
  "https://agent-gateway-kappa.vercel.app/v1/frostbyte-wallet/v1/wallet/balance/0x742d35Cc6634C0532925a3b844Bc9e7595f2bD08?chain=ethereum"

{
  "address": "0x742d35Cc6634C0532925a3b844Bc9e7595f2bD08",
  "chain": "ethereum",
  "nativeBalance": "1.2345",
  "nativeSymbol": "ETH",
  "nativeValueUsd": "$2,469.00",
  "tokens": [
    {"symbol": "USDC", "balance": "500.00", "contract": "0xa0b8..."},
    {"symbol": "WETH", "balance": "0.5", "contract": "0xc02a..."}
  ]
}

Cross-Chain Token Swaps

Get a Swap Quote

# Get quote for ETH -> USDC swap
curl -H "x-api-key: YOUR_KEY" \
  "https://agent-gateway-kappa.vercel.app/v1/frostbyte-wallet/v1/swap/quote?chain=ethereum&fromToken=ETH&toToken=USDC&amount=1.0"

{
  "fromToken": "ETH",
  "toToken": "USDC",
  "fromAmount": "1.0",
  "toAmount": "2000.50",
  "priceImpact": "0.02%",
  "fee": "0.3%",
  "route": "ETH → WETH → USDC (Uniswap V3)",
  "estimatedGas": "150000",
  "validFor": 30
}

Execute the Swap

# Execute the swap
curl -X POST "https://agent-gateway-kappa.vercel.app/v1/frostbyte-wallet/v1/swap/execute" \
  -H "x-api-key: YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "walletId": "wal_7f3a9b2c",
    "chain": "ethereum",
    "fromToken": "ETH",
    "toToken": "USDC",
    "amount": "1.0",
    "slippage": 0.5
  }'

{
  "orderId": "swap_abc123",
  "status": "pending",
  "txHash": "0x1234...abcd",
  "estimatedCompletion": "2026-03-04T12:01:30Z"
}

Supported Chains

Use Cases

AI Agent with a Wallet

Give your AI agent the ability to hold, send, and receive crypto. Create a wallet during agent initialization, fund it, and let it autonomously make transactions based on its logic. See our tutorial: Crypto Portfolio Tracker.

Payment Processing

Accept crypto payments in your app. Create a unique wallet per customer/order, monitor for incoming transactions, and auto-forward funds to your main wallet.

Portfolio Tracker

Query balances across all 9 chains for a given address. Aggregate native tokens + ERC-20/SPL tokens to build a complete portfolio view.

DeFi Aggregator

Use the swap endpoints to find the best rates across DEXes. Get quotes from multiple chains and execute swaps with a single API call.

Pricing

Wallet operations cost 3 credits ($0.003) per API call: creating wallets, checking balances, listing transactions. Swap quotes are 1 credit. Swap execution is 10 credits plus a 0.3% fee on the swap amount.

You get 200 free credits when you create an API key — enough for 66 wallet operations or 200 swap quotes.

Compared to Alternatives

Security Notes

• Mnemonic phrases are returned once during wallet creation. Store them securely — they cannot be retrieved later.
• Private keys are derived from the mnemonic using BIP44 derivation paths. The API does not store private keys.
• API keys are scoped to your account. Rotate them if compromised.
• For production use, we recommend keeping large balances in cold storage and using API wallets for operational amounts only.

FAQ

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