Smart Contract Labs
Hands-on practice with real on-chain interactions on Sepolia testnet.
intermediateSepolia
ERC-20 Approve Lab
Call approve() on a real token, estimate gas before signing, and verify the Approval event on-chain.
- →Read current allowance(owner, spender) before acting
- →Simulate the call to get a gas estimate before signing
- →Sign and broadcast approve() with your wallet
- →Verify the Approval event in the transaction logs
beginnerSepolia
ERC-20 Token Inspector
Call view functions on a live ERC-20 contract on Sepolia. No wallet required to read.
- →Call view functions: name(), symbol(), decimals()
- →Read totalSupply() and format it correctly with decimals
- →Query balanceOf() for any address
- →Understand the difference between raw uint256 and formatted values
intermediateHardhat Local
Hardhat Counter Lab
Interact with a Counter contract on your local Hardhat node. No testnet ETH needed — instant confirmations.
- →Start a local Hardhat node and deploy the Counter contract
- →Connect MetaMask to localhost:8545 (chain 31337)
- →Read on-chain state: count() and owner()
- →Call increment(), decrement(), and reset() (access control)
- →Inspect Incremented / Decremented events in the transaction monitor
beginnerSepolia
Transaction Lifecycle Lab
Send a real Sepolia transaction and observe every phase: pending → confirming → confirmed.
- →Connect wallet and switch to Sepolia testnet
- →Send a 0 ETH self-transaction (only gas cost)
- →Track tx hash, pending state, and block confirmation
- →Verify the transaction on Etherscan
intermediateSepolia
Swap & Staking Simulation Lab
Walk through a token swap (approve + execute) and a staking lifecycle (stake → earn → unstake). Real balance reads on Sepolia; swap and stake steps are simulated.
- →Read live token balance and simulate a swap quote with slippage tolerance
- →Approve a router contract via a real on-chain call
- →Observe the full swap state machine: pending → confirming → success
- →Configure a staking position with lock duration and projected APY
- →Walk through the stake → rewards → unstake lifecycle and its QA checklist