📋 Smart Contracts
Last verified: April 2026Self-executing code on a blockchain. A smart contract runs exactly as programmed when conditions are met — no intermediary, no human required to enforce it.
What a smart contract is
A smart contract is a program stored on a blockchain that runs automatically when its conditions are met. Think of it as a vending machine rather than a cashier: you put in the right input, and it dispenses the right output, with no human needed to approve or process the deal. Once deployed, it executes exactly as written, the same way every time, visible to anyone, and — usually — unchangeable. This is the technology that turned blockchains from simple payment ledgers into general-purpose platforms.
How they work
A developer writes the contract's rules in code and deploys it to a blockchain that supports smart contracts (Ethereum was the pioneer; many others now do too). The code lives at an address, and anyone can interact with it by sending a transaction. The network's computers all execute the code and agree on the result, so the outcome is trustworthy without any party being in charge. The contract can hold and move funds, enforce conditions, and call other contracts.
Composability: the Lego effect
Because smart contracts are open and can call one another, they combine like Lego bricks. A user can take tokens from a lending contract, use them as collateral in a trading contract, and deposit the result into a yield contract — all in a single transaction. This "composability" is what makes decentralised finance so powerful and so fast-moving: developers build on each other's contracts without asking permission.
The risks
Smart contracts are only as good as their code, and code has bugs. Because they're often immutable and hold real money, a flaw can be catastrophic and irreversible — DeFi protocols and bridges have lost enormous sums to exploits. Audits by security firms reduce this risk but don't eliminate it. The lesson for users: favour established, audited contracts, and understand that interacting with a smart contract means trusting its code, not a company you can call.
What they enable
Smart contracts power most of what's interesting in crypto beyond simple payments: decentralised exchanges, lending markets, stablecoins, NFTs, DAOs, and on-chain games. Whenever you hear about a "protocol" or a "dApp" (decentralised application), there are smart contracts underneath doing the work.
Smart contracts and DAOs
One striking use of smart contracts is the DAO — a Decentralised Autonomous Organisation. Instead of a company run by executives, a DAO encodes its rules (how funds are spent, how votes are counted) in smart contracts, and token holders vote on decisions that the contracts then execute automatically. It's an experiment in running an organisation as transparent code rather than through trusted management — powerful, but only as sound as the code and the community behind it.
The India angle
For an Indian user, the practical point is that interacting with a smart contract — swapping, lending, staking — is transacting in Virtual Digital Assets, so the 30% tax and 1% TDS rules apply, and each interaction is a record to keep. The contract won't withhold tax or issue a statement; that responsibility is yours, especially when using DeFi protocols rather than an Indian exchange.