🪙 Stablecoin Transactions

Once your users have deposited funds, your platform needs to let them send, withdraw, or transfer stablecoins.
With Tatum’s blockchain transaction APIs, you can execute on-chain stablecoin transfers without handling private keys directly — or by using your own secure signing service.

📘

Blockchain Transfer API (Popular 💸)

• POST /v4/blockchain/token/transaction — Send ERC-20 stablecoins (USDC, USDT, DAI, etc.) between addresses.
• POST /v4/blockchain/transfer — Transfer native assets like ETH or MATIC.
• POST /v4/blockchain/transaction/broadcast — Broadcast a signed raw transaction.

Explore Docs →

Key Use Cases

• User Withdrawals: Let users send stablecoins to external wallets.
• Internal Transfers: Move assets between user-owned wallets managed by your platform.
• Merchant Payouts: Automate USDC/USDT payments to suppliers or vendors.
• Batch Payments: Queue multiple transfers and send them programmatically.
• Cross-App Integrations: Connect stablecoin transfers to your payment or reward systems.

Example – Send USDC from One Wallet to Another (cURL)

curl --request POST \
     --url 'https://api.tatum.io/v3/ethereum/transaction?testnetType=ethereum-sepolia' \
     --header 'accept: application/json' \
     --header 'content-type: application/json' \
     --header 'x-api-key: YOUR_API_KEY' \
     --header 'x-testnet-type: ethereum-sepolia' \
     --data '
{
  "currency": "USDC",
  "to": "0x687422eEA2cB73B5d3e242bA5456b782919AFc85",
  "amount": "100",
  "fromPrivateKey": "YOUR_PRIVATE_KEY"
}
'

const options = {
  method: 'POST',
  headers: {
    accept: 'application/json',
    'x-testnet-type': 'ethereum-sepolia',
    'content-type': 'application/json',
    'x-api-key': 'YOUR_API_KEY'
  },
  body: JSON.stringify({
    currency: 'USDC',
    to: '0x687422eEA2cB73B5d3e242bA5456b782919AFc85',
    amount: '100',
    fromPrivateKey: 'YOUR_PRIVATE_KEY'
  })
};

fetch('https://api.tatum.io/v3/ethereum/transaction?testnetType=ethereum-sepolia', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

Sample Response

{  
  "txId": "0x0a72d22977cbab734bb9b53b78e4a4e58d4f1f8d8131c6e1e086e5936cf10df2"  
}  

Recommended Flow

[User Action] → [App Backend] → [Tatum API Transaction Request] → [Blockchain Broadcast] → [Webhook Confirmation]  

1. User Initiates Transfer

User requests a withdrawal or transfer of a specific stablecoin.

2. App Calls Tatum API

Your backend uses the Blockchain Transfer endpoint to send the transaction.

3. Transaction Broadcast

Tatum signs (if private key provided) and broadcasts the transaction to the blockchain.

4. Confirmation

Once mined, your app receives a webhook from the Deposit Tracking system confirming the transfer if you have the Notifications setup on the address.

Optional: Offline Signing

If you prefer not to expose private keys to your backend, Tatum supports offline signing:

1. Generate the transaction payload using `ethblockchaintransfer` with `"signatureId"` instead of `"fromPrivateKey"`.
2. Sign it offline using your own key management or HSM.
3. Broadcast it later with `POST /v4/blockchain/transaction/broadcast`.  

This setup ensures secure, auditable handling of all withdrawals.

Example – Prepare a Transaction for Offline Signing

curl --request POST \
     --url 'https://api.tatum.io/v3/ethereum/transaction?testnetType=ethereum-sepolia' \
     --header 'accept: application/json' \
     --header 'content-type: application/json' \
     --header 'x-api-key: t-66a730ccccfd17001c479705-2f597d14ad7543f289a03418' \
     --header 'x-testnet-type: ethereum-sepolia' \
     --data '
{
  "currency": "USDC",
  "to": "0x687422eEA2cB73B5d3e242bA5456b782919AFc85",
  "amount": "100000",
  "signatureId": "YOUR_KMS_SIGNATURE_ID"
}
'

Gas & Fee Estimation

Before executing transfers, you can estimate the gas or miner fee using Tatum’s Fee Estimation API.

curl --request GET \
     --url https://api.tatum.io/v3/blockchain/fee/ETH \
     --header 'accept: application/json' \
     --header 'x-api-key: YOUR_API_KEY'

{
  "slow": 778433798,
  "medium": 778597061,
  "fast": 778876940,
  "baseFee": 778410475,
  "time": "2025-10-21T14:43:33.922Z",
  "block": 23626608
}

Use this to display estimated fees before user confirmation.

FAQs

Best Practices

• ✅ Always verify user balances before sending transfers (see Wallet Portfolio).
• 🧩 Use fee estimation before broadcasting to prevent out-of-gas failures.
• 🧱 Implement idempotent transaction logic — don’t resend the same withdrawal twice.
• 🔐 Use offline signing or custody integration for production-grade security.
• 🔁 Combine with Transaction Alerts to confirm delivery and update balances.

By integrating Tatum’s transaction APIs, your app gains secure, reliable stablecoin transfer capabilities across major blockchains — with minimal infrastructure and full flexibility.