Solidity Study Guide 2026
Everything you need to pass the Solidity exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📋 Solidity Exam Format at a Glance
📚 Solidity Topics to Study (25)
✍️ Sample Solidity Questions & Answers
1. Which Solidity type correctly declares a fixed-size byte array of exactly 32 bytes?
bytes32 is Solidity's built-in fixed-size byte array type that holds exactly 32 bytes.
2. What is the gas benefit of using `unchecked` arithmetic blocks in Solidity 0.8+?
Wrapping arithmetic in `unchecked {}` disables the compiler-inserted overflow checks, saving gas when you have already proven the values cannot overflow.
3. What is a 'price oracle manipulation' attack in DeFi?
Attackers use large capital (often flash loans) to move prices on a DEX that a protocol uses as an oracle, triggering profitable liquidations or under-collateralized borrows.
4. What does 'assert()' do differently from 'require()' in Solidity?
assert() consumes all remaining gas and is for invariant checks; require() refunds gas and is for preconditions.
5. What's an example of a calldata?
Calldata is a special data location in Solidity used for function arguments of external calls. It is a read-only, non-modifiable area that exists only for the duration of a function call. This data resides in the EVM's memory space, providing an efficient way to pass arguments without modifying persistent storage.
6. What vulnerability arises when Solidity arithmetic operations exceed the maximum or minimum value of the data type?
Integer overflow/underflow occurs when arithmetic results exceed the bounds of the integer type, wrapping around to unexpected values.