Spark Fi — Earn Real Yield on Your Stablecoins
The Spark Fi platform lets you deposit USDC, USDT, ETH, and PYUSD into audited on-chain savings accounts and watch your balance grow — transparently, automatically, every block.
Open the App Learn How It WorksWhy Spark Fi
Most savings products hide their mechanics behind opaque terms. Spark Fi's protocol publishes every rate change on-chain the moment it happens. Here is what that means in practice.
Rates you can actually verify
The APY shown in the interface is the same number encoded in the smart contract. No marketing inflators, no undisclosed fees reducing your return.
No lock-up, no minimums
Deposit $1 or $1 million. Withdraw tomorrow or in three years. Standard savings accounts on the Spark Fi platform impose zero mandatory holding periods.
Non-custodial by design
Your funds sit in audited Ethereum smart contracts — not in a company bank account. The team behind Spark Fi cannot freeze, redirect, or confiscate deposited assets.
Backed by battle-tested collateral
Yields are generated from over-collateralised lending activity. Ethereum's smart contract model enforces liquidation rules automatically if collateral falls below the required threshold.
How It Works
Getting started takes less time than making a cup of coffee. Below is the full flow from zero to earning.
Connect your wallet
Use any EIP-1193 compatible wallet — MetaMask, Coinbase Wallet, WalletConnect-enabled apps. The Spark Fi platform does not store credentials.
Pick a savings account
Choose between spUSDC (currently 3.65 % APY), spUSDT, spETH, spPYUSD, and USDS. Each account is a separate ERC-4626 vault with its own rate feed. Check the knowledge base for a side-by-side comparison.
Approve and deposit
Sign a one-time ERC-20 approval, then confirm the deposit transaction. Gas costs on Ethereum Mainnet typically run $2–$8 at normal congestion. Polygon-based deployments cost a fraction of that.
Yield accrues every block
Interest compounds continuously. Your vault token balance (spUSDC, for example) increases in real time — no manual claiming needed.
Withdraw whenever you want
Redeem your vault tokens for the underlying asset at any time. The contract calculates your exact share of accrued yield at the moment of withdrawal. Read about the team's approach to liquidity management.
Key Features
ERC-4626 vault standard
Every savings account follows the Ethereum-native ERC-4626 vault spec, making it composable with Forge-based testing suites and hundreds of third-party integrations without custom adapter code.
Multi-asset support
Five assets live right now: USDC, USDT, USDS, ETH, PYUSD. The development team is evaluating additional stablecoins in parallel with Polygon expansion talks.
On-chain rate transparency
APY updates are written to the contract — not just the frontend. Anyone can query the rate directly using a block explorer, no API key required.
SPK governance token
The SPK token lets holders vote on protocol parameters — including interest rate models and supported collateral types. Governance proposals go through a public timelock before execution.
SparkLend borrowing
Want leverage? SparkLend — the lending arm of Spark Fi's protocol — lets you post collateral and borrow against it. Rates are variable and determined by utilisation curves, not a committee.
Sandbox mode
New to DeFi? Try every feature with simulated funds in Sandbox mode before risking real assets. It runs against a forked Mainnet state, so numbers reflect real market conditions.
Higher-yield opportunities
Beyond standard savings, Spark Fi surfaces curated higher-yield vaults — like Sky stUSDS at 7.16 % APY — with clear risk disclosures alongside each option.
Spark Fi by the Numbers
These figures reflect the protocol's scale as of early 2025. They change frequently — the live dashboard on the app shows real-time data.
FAQ
What is Spark Fi?
Spark Fi is a decentralized savings protocol built on Ethereum. You deposit stablecoins or ETH into audited smart contracts and earn a transparent, on-chain APY — no bank, no middleman, no hidden fees.
How do I start earning on Spark Fi?
Connect a Web3 wallet. Pick a savings account — USDC, USDT, ETH, or PYUSD. Enter the amount, confirm two transactions (approve + deposit), and yield starts accruing immediately. The whole process takes under five minutes.
Is Spark Fi safe and audited?
The Spark Fi platform's smart contracts have been reviewed by multiple independent security firms. The protocol is fully non-custodial — assets are held in on-chain vaults, not in any company's balance sheet. No single entity can access user funds. Read the full security overview.
Can I withdraw at any time if I need liquidity?
Yes. Standard savings vaults have no lock-up. Withdrawals process instantly on-chain, subject to available liquidity in the vault. The liquidity dashboard (linked from the app header) shows the real-time buffer before your transaction.
Why should I use Spark Fi instead of a traditional savings account?
Traditional savings accounts pay rates set privately and changed without notice. Spark Fi's protocol encodes rates in smart contracts visible to anyone. The difference is not just higher APY — it's verifiability. Anyone can audit the math at any block height.
Which networks does Spark Fi support?
Spark Fi is live on Ethereum Mainnet today. The team behind Spark Fi is actively assessing deployment on additional EVM networks, including Polygon, to bring gas costs down for smaller depositors. Follow official channels for announcements.