# FAQ > Frequently asked questions about Senddy. Source: https://www.senddy.com/docs/faq Last modified: 2026-08-02T02:33:05.000Z --- ## General ### What is Senddy? Senddy is a privacy-preserving payment platform that lets you hold, send, and spend digital dollars privately. It uses zero-knowledge proofs to verify transactions without revealing details like amounts, senders, or recipients. ### Is Senddy a bank? No. Senddy is not a bank. It is a non-custodial payment platform — your funds are held in audited smart contracts on the Base blockchain, not in a bank account. We cannot access, freeze, or control your funds. ### What currency does Senddy use? Senddy uses USDC, a digital dollar issued by Circle and backed 1:1 by US dollars and short-term treasuries. You don't need to know anything about cryptocurrency to use Senddy — when you deposit from your bank, the conversion happens automatically. ### Is Senddy free? Yes, Senddy is free to use for basic features. There are no monthly fees, no minimum balances, and no hidden charges. Transactions between Senddy users cost less than $0.005 to cover on-chain verification. ## Privacy ### How is my privacy protected? Every transaction uses a zero-knowledge proof that verifies the payment is valid without revealing the amount, sender, or recipient. Your balance is computed locally on your device — it's never stored on a server or visible on the blockchain. ### Can deposits be linked to my Senddy account? Senddy generates a fresh Base address for each direct USDC deposit instead of reusing your smart-wallet address. After the deposit is shielded, that address is retired. This removes the permanent recipient identifier that would otherwise make it easy to group all deposits into one Senddy account. The original blockchain transfer remains public. Observers can still see its source, amount, and timing, and these details may permit correlation. Repeatedly funding from the same self-custody wallet can also link those funding transfers to each other. ### Who can see my transactions? Only you. Unlike traditional banks and payment apps, Senddy's zero-knowledge technology ensures your transaction history is completely private. Not even Senddy can see your activity. ### Can Senddy freeze my funds? No. Senddy is non-custodial. Your funds are in a smart contract that only responds to valid zero-knowledge proofs signed with your private key. No one else can move your money. ### Does Senddy sell my data? Never. We have no transaction data to sell. Your activity is cryptographically hidden from everyone, including us. ## Money ### How do I add money? You can fund your Senddy account through: - **Bank transfer (ACH)** — Connect any of 12,000+ US banks - **Debit or credit card** — Visa, Mastercard - **Venmo or Cash App** — Transfer from existing payment apps - **Stablecoins** — Send USDC from Ethereum, Solana, Base, or other supported networks - **Direct deposit** — Route your paycheck to Senddy ### How do I withdraw? Withdraw to your bank account (ACH), to any Ethereum address, or cash out via supported payment methods. There are no minimum withdrawal amounts. ### How does yield work? Your balance earns yield automatically from trusted DeFi lending protocols. Rates are approximately 3-4% APY — roughly 10x what a traditional savings account pays. There are no lockup periods, and you can withdraw at any time. ### What is the Senddy Card? The Senddy Prepaid Card is a non-reloadable virtual card funded from your private USDC balance. Create a card for $5 to $1,000 and use it at supported U.S. online merchants. The current flow does not require an ID upload, but the card provider and issuer still apply normal transaction monitoring and program controls. ## Technical ### What blockchain is Senddy built on? Senddy runs on Base, a Layer 2 network built on Ethereum by Coinbase. Base provides fast finality, low costs, and the security of Ethereum. ### Do I need crypto knowledge? No. Senddy handles all blockchain interactions behind the scenes. You fund from your bank, send by username, and spend with a card. No wallets, gas tokens, or seed phrases required. ### How fast are transactions? Zero-knowledge proofs are generated on your device in 2-5 seconds. After that, the transaction is submitted to Base and confirms in seconds. Most payments feel instant. ### What if I lose my device? Your Senddy keys are derived from your login credentials (email, Google, or wallet signature). You can recover your account by signing in on a new device — your keys are deterministically regenerated, and the sync engine rebuilds your note state from on-chain data.