DeFi Basics

Welcome to the Intermediate track. You finished the Beginner lessons knowing what blockchains, wallets, keys, and coins are. Now you will learn what people actually do with that technology — starting with one of its biggest ideas: Decentralised Finance, or DeFi.

> Educational note: This lesson explains how DeFi works. It is not financial advice, and nothing here is a suggestion to use, deposit into, or invest in any protocol.

Banking Without Banks

Decentralised Finance (DeFi) is a set of financial services built on public blockchains — mostly Ethereum and similar networks. Lending, borrowing, trading, and earning interest all happen through smart contracts: code that executes automatically when conditions are met.

Compare that with traditional finance. To earn interest on savings in India, you open a bank account, the bank lends your money out, keeps most of the profit, and pays you a small cut. In DeFi, you interact directly with a smart contract: you deposit crypto, borrowers borrow it, and the interest flows to you automatically.

For now, just remember: smart contracts are the engine; DeFi is the car.

What Can You Do in DeFi?

Lend and earn interest

You deposit crypto into a lending protocol — a smart contract that pools deposits from many users. Borrowers draw from the pool and pay interest, which is distributed to lenders automatically. Interest rates adjust in real time based on supply and demand: when many people want to borrow, rates rise; when few do, rates fall.

Borrow against your crypto

You can lock up crypto as collateral and borrow other crypto against it. Because there is no credit check, the loan is over-collateralised — you might lock up ₹1,50,000 worth of crypto to borrow ₹1,00,000. If your collateral's value drops too far, the smart contract automatically sells some of it to repay the loan. This automatic sale is called liquidation, and it is one of DeFi's harshest lessons for beginners.

Swap tokens instantly

Decentralised exchanges (DEXs) let you trade one token for another directly from your wallet — no account, no KYC, no order book. The most common design uses liquidity pools: big pots of token pairs that anyone can trade against. Prices are set by a mathematical formula based on the ratio of tokens in the pool.

Provide liquidity and earn fees

You can deposit a pair of tokens into a liquidity pool. Every time someone trades against that pool, they pay a small fee — and you earn a share of it, proportional to your deposit.

Yield farming

This is the practice of moving funds between protocols chasing the highest returns — lending here, providing liquidity there, collecting reward tokens everywhere. It can be profitable and is extremely complex and risky. Treat it as advanced territory, not a starting point.

Try it yourself: mental exercise

Imagine you have ₹10,000 in a savings account earning 4% a year. Now imagine a DeFi lending pool offering a much higher rate on a crypto deposit. Before you touch it, list three questions you would want answered first. (Good answers: what happens if the smart contract has a bug? What happens if the token's price crashes? Can I withdraw anytime, or is there a lock-up?) If you cannot answer those, you are not ready to deposit — and that instinct is exactly right.

The Risks Are Real

DeFi's honesty requires stating this plainly: people lose money in DeFi regularly, and usually through one of these channels:

• Smart-contract bugs. Code can have flaws. When a bug is exploited, entire pools can be drained in seconds, and there is no customer support to reverse it. Even audited protocols have been hacked.
• Impermanent loss. When you provide liquidity and the two tokens' prices move apart, you can end up with less value than if you had simply held the tokens. The trading fees you earn may not cover the difference. The name is misleading — the loss becomes very permanent if you withdraw while prices are diverged.
• Rug pulls. Some projects are outright scams: anonymous teams launch a token, attract deposits, then disappear with the funds. If the team is anonymous and the code is unaudited, assume the worst.
• Liquidation cascades. In a market crash, falling collateral triggers automatic liquidations, which push prices down further, triggering more liquidations. Borrowers can lose their collateral in minutes during extreme volatility.
• Oracle manipulation. Smart contracts rely on oracles — data feeds that report real-world prices. If an attacker manipulates the price feed, the contract acts on false information.

A Beginner's Mindset for DeFi

If you ever explore DeFi beyond reading about it, these principles separate learners from casualties:

1. Start with established, audited protocols. The ones that have operated for years, published multiple security audits, and hold large amounts of value are still risky — but far less risky than a two-week-old project promising triple-digit returns.
2. Use small amounts you can afford to lose. Your first DeFi interaction should be an amount so small that losing all of it would not affect your life. This is tuition, not investment.
3. Read the documentation. Every legitimate protocol publishes docs explaining exactly how it works. If you cannot find docs — or cannot understand them — do not deposit.
4. Beware of yields that look too good. In finance, extraordinary returns always come with extraordinary risk. A protocol offering 100% annual returns is not a gift; it is a warning sign.
5. Never deposit life savings. No matter how safe something looks, smart-contract risk can never be reduced to zero.

DeFi in the Indian Context

A few India-specific points worth knowing:

• No regulatory safety net. Indian regulators have not licensed DeFi protocols, and there is no deposit insurance. If a protocol is exploited, there is no authority to appeal to — Indian or otherwise.
• Taxes still apply. Every DeFi interaction — swapping, earning interest, receiving rewards — can be a taxable event under India's 30% crypto tax regime, with 1% TDS on transfers. DeFi's complexity makes record-keeping harder, not optional. The tax lesson later in this track will cover this properly.
• INR on-ramps. You cannot deposit rupees directly into a DeFi protocol. You buy crypto on an Indian exchange first, move it to your own wallet, then interact with DeFi. Each hop adds fees and tax considerations.

*Tax note: crypto tax rules can change — the 30% rate and 1% TDS described here were current as of September 2026. Verify the latest rules before filing.*

Key Takeaways

• DeFi recreates financial services — lending, borrowing, trading — using smart contracts instead of banks.
• The main activities are lending, borrowing against collateral, swapping on DEXs, providing liquidity, and yield farming.
• The main risks are smart-contract bugs, impermanent loss, rug pulls, liquidations, and oracle manipulation.
• A beginner's approach: established protocols only, tiny amounts, read the docs, distrust extraordinary yields.
• In India, DeFi has no regulatory protection and every interaction can trigger the 30% tax — track everything.
• This lesson is educational only. Nothing here suggests using or investing in any protocol.