What is a smart contract?
DefinitionA smart contract is a program stored on a blockchain that runs automatically when it receives a transaction, exactly as its code says. Tokens, decentralized exchanges and on-chain escrow are all smart contracts, and they carry out their rules without a middleman.
How smart contracts work
A smart contract has its own address on the blockchain, a balance and some stored data. When you send it a transaction, the network’s nodes run the same code and agree on the result, so the outcome doesn’t depend on trusting a company to carry it out.
Running code costs fees, paid in the network’s coin: gas on Ethereum and other EVM networks, energy on Tron and TON on TON. On TON, even your wallet is a smart contract, and new wallets usually use the W5 version.
Everyday examples
You probably use smart contracts already, often without noticing:
- Tokens: USDT and other tokens are contracts that track who holds what
- Escrow: funds stay locked until both sides confirm or a dispute is resolved
- Swaps: decentralized exchanges trade tokens from pools of liquidity
- Gift and payment contracts that release funds when a condition is met
Risks to understand
Code runs exactly as written, bugs included. A flaw in a contract can let attackers drain it, and transfers it makes can’t simply be undone. Some contracts are upgradeable or have an owner with special powers, such as freezing tokens, so “on-chain” doesn’t automatically mean nobody is in control.
Using a contract can also grant it permissions. A token approval lets a contract spend your tokens until you revoke it, which is why phishing sites ask for approvals.
Smart contracts in Waletifi
Waletifi uses smart contracts where trust matters most. In P2P trading, the seller’s USDT is locked in an on-chain escrow contract before you pay. On Raste, each order is paid into its own escrow contract on TON, gift links use a one-off gift contract, and your TON wallet itself is a W5 contract.
