Beginner interview questions for Rust in Solana Blockchain Development

Here are Most asking questions with answers on Rust in Solana Blockchain Development

Basics of Solana and Rust

1. What is Solana?
   Solana is a excessive-overall performance blockchain known for its speedy transaction speeds and coffee fees, the usage of Proof of History (PoH) for scalability.
2. Why use Rust for Solana clever contracts? Rust is memory-safe, speedy, and stops commonplace security troubles, making it ideal for blockchain development.
3. What is a Solana Program?
   A Solana Program is a clever agreement deployed at the Solana blockchain, written in Rust or C.
4. How does Solana differ from Ethereum?
   Solana makes use of PoH and parallel transaction execution, while Ethereum makes use of Proof of Stake (PoS) and serial execution.
5. How do you install Rust for Solana development?
   Install Rust using curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
6. What is the Solana CLI?
   It is a command-line tool to interact with the Solana blockchain. Install it using sh -c "$(curl -sSfL https://release.solana.com/stable/install)"
7. How do you create a new Solana program? cargo install --git https://github.com/solana-labs/anchor anchor-cli anchor init my_program
8. What is Anchor in Solana?
   Anchor is a Rust framework that simplifies Solana smart contract development with predefined macros and utilities.
9. What is the default programming model in Solana?
   Solana follows an account-based model rather than an Ethereum-like state machine.
10. How do Solana accounts work?
    Accounts store data and program state, acting as persistent storage for Solana programs.

Rust Programming in Solana

11. What Rust dependencies are needed for Solana smart contracts?
    • solana-program
    • borsh
    • anchor-lang
    • anchor-spl
12. What is the entry point of a Solana program? entrypoint!(process_instruction);
13. How do you serialize and deserialize data in Solana programs?
    Use Borsh for efficient serialization: #[derive(BorshSerialize, BorshDeserialize)] pub struct MyData { pub count: u64, }
14. How do you define a Solana instruction? #[derive(AnchorSerialize, AnchorDeserialize)] pub struct MyInstruction { pub amount: u64, }
15. How do you handle accounts in Solana? #[account(mut)] pub my_account: Account<'info, MyData>,
16. What is the difference between ProgramAccount and UncheckedAccount?
    ProgramAccount is a safe wrapper for deserialized accounts, while UncheckedAccount is a raw Solana account.
17. How do you implement a Solana program? #[program] pub mod my_program { use super::*; pub fn initialize(ctx: Context<Initialize>) -> ProgramResult { let my_account = &mut ctx.accounts.my_account; my_account.count = 0; Ok(()) } }
18. What is Context in Anchor?
    Context<T> provides access to accounts and program data.
19. How do you log messages in Solana smart contracts? msg!("Transaction executed successfully!");
20. What is AccountInfo in Solana?
    It is a struct that provides metadata about a Solana account, including its owner and lamports.

Solana Transactions & Accounts

21. What are lamports?
    The smallest unit of SOL (1 SOL = 1 billion lamports).
22. How do you send SOL in a Solana program? invoke( &system_instruction::transfer(&from.key, &to.key, amount), &[from.clone(), to.clone(), system_program.clone()], )
23. How do you check the balance of an account? solana balance <ACCOUNT_ADDRESS>
24. How do you create a PDA (Program Derived Address)? let pda = Pubkey::create_program_address(&[b"seed"], program_id)?;
25. What is CPI (Cross-Program Invocation) in Solana?
    Calling one Solana program from another.
26. How do you call another Solana program from within a program? invoke_signed( &instruction, &[account.clone()], &[&[b"seed", &[bump]]], )
27. What is the difference between invoke and invoke_signed?
    invoke_signed allows the use of PDAs with signatures.
28. How do you sign a transaction in Solana? solana transaction sign --signer <keypair.json>
29. How do you deploy a Solana program? solana program deploy target/deploy/my_program.so
30. How do you check the logs of a Solana program? solana logs

Solana Anchor Framework

31. What is #[account] in Anchor?
    A macro that defines account structures.
32. How do you initialize an account using Anchor? #[derive(Accounts)] pub struct Initialize<'info> { #[account(init, payer = user, space = 8 + 8)] pub my_account: Account<'info, MyData>, pub user: Signer<'info>, }
33. What does #[instruction(...)] do in Anchor?
    Passes extra parameters into the program.
34. What is the purpose of #[derive(Accounts)]?
    It simplifies account validation.
35. How do you generate an IDL (Interface Definition Language) for a Solana program? anchor build

Testing & Debugging

36. How do you test Solana smart contracts? anchor test
37. What testing framework is used in Solana?
    Mocha with JavaScript or Rust’s built-in test framework.
38. How do you simulate transactions locally? solana-test-validator

Advanced Topics

39. How do you upgrade a Solana program? solana program deploy --upgrade
40. What is a Token Account in Solana?
    A special account used for holding SPL tokens.
41. How do you mint an SPL token? spl-token mint <TOKEN_ADDRESS> <AMOUNT>

Security in Solana Smart Contracts

42. What are common security risks in Solana smart contracts?

• Missing account validation
• Unchecked arithmetic overflows
• Privilege escalation attacks
• Unvalidated cross-program invocations

43. How do you prevent reentrancy attacks in Solana?
    Solana transactions are atomic, preventing external reentrancy. However, ensure proper account validation and program flow.
44. What is an unchecked account in Solana?
    UncheckedAccount allows access to any account but does not enforce ownership or data validation.
45. How do you ensure only the expected user modifies an account?

if ctx.accounts.my_account.owner != ctx.accounts.signer.key {
    return Err(ProgramError::IncorrectProgramId);
}

46. How do you verify the signer of a transaction?

if !ctx.accounts.signer.is_signer {
    return Err(ProgramError::MissingRequiredSignature);
}

47. How do you securely transfer tokens in Solana?
    Use the spl-token program with explicit authorization checks before transfers.
48. How can you prevent integer overflows in Solana programs?
    Use Rust’s checked_add(), checked_sub(), and checked_mul() instead of direct arithmetic.
49. What is require! in Anchor?
    A macro to enforce conditions:

require!(amount > 0, ErrorCode::InvalidAmount);

50. How do you validate a PDA (Program Derived Address) before using it?

let (expected_pda, _) = Pubkey::find_program_address(&[b"seed"], program_id);
require!(pda.key == expected_pda, ErrorCode::InvalidPDA);

51. How do you restrict instruction execution to the program owner?
    Validate the program ID before processing logic.
52. How do you ensure that an instruction modifies an account only if necessary?
    Use AccountInfo::is_writable to check before modifying.
53. How do you prevent unauthorized CPI (Cross-Program Invocations)?
    Validate accounts before executing invoke or invoke_signed.

DeFi on Solana

54. What is an AMM (Automated Market Maker) on Solana?
    A decentralized protocol that facilitates trading via liquidity pools (e.g., Raydium, Serum).
55. How do you interact with an AMM using Rust?
    Use the serum_dex or raydium crate for programmatic trading.
56. What is a Solana lending protocol?
    A protocol like Solend or Jet that enables lending and borrowing of assets.
57. How do you create a DeFi vault on Solana?

• Define a vault account
• Store deposited funds
• Implement a withdrawal function with ownership validation

58. How do you interact with the Solana Token Program?

let mint = ctx.accounts.token_mint.key();
let authority = ctx.accounts.user.key();
let amount = 100;
let cpi_accounts = Transfer {
    from: ctx.accounts.source.to_account_info(),
    to: ctx.accounts.destination.to_account_info(),
    authority: ctx.accounts.owner.to_account_info(),
};

59. How do you calculate swap rates in a Solana AMM?
    Use the constant product formula:

x * y = k

where x and y are reserves of two assets, and k is a constant.

60. How do you create a staking smart contract in Solana?

• Store staked token balance
• Apply time-based rewards
• Ensure proper withdrawals

61. How do you prevent flash loan attacks in Solana DeFi protocols?

• Use time-based lockups
• Verify collateralization ratios
• Implement withdrawal limits

NFT Development on Solana

62. What is an NFT on Solana?
    A unique, non-fungible token following the Metaplex standard.
63. What is Metaplex?
    A framework for creating, managing, and selling NFTs on Solana.
64. How do you mint an NFT on Solana?

metaplex upload assets/
metaplex create_candy_machine

65. How do you create an NFT metadata account?

let metadata = Metadata {
    name: "MyNFT".to_string(),
    symbol: "NFT".to_string(),
    uri: "https://example.com/metadata.json".to_string(),
};

66. What is a Candy Machine?
    A Metaplex protocol that automates NFT minting.
67. How do you transfer an NFT in Solana?
    Use the spl-token transfer instruction.
68. What are royalties in Solana NFTs?
    Fees paid to the original creator on resale, enforced by the Metaplex standard.
69. How do you list an NFT for sale on a Solana marketplace?

• Use Metaplex auctions
• Interact with the Solana Program Library (SPL)

70. How do you verify NFT ownership in Solana?
    Check the token account’s metadata.
71. How do you create a fractionalized NFT on Solana?

• Create SPL tokens representing fractional ownership.

Solana Validator Setup

72. What is a Solana Validator?
    A node that validates transactions and secures the network.
73. How do you set up a Solana validator?

solana-install init
solana-validator --identity validator-keypair.json

74. How do you generate a validator keypair?

solana-keygen new --outfile validator-keypair.json

75. How do you check the current Solana epoch?

solana epoch-info

76. How do you stake SOL as a validator?

solana create-stake-account stake-keypair.json 1000

77. How do you monitor validator performance?

solana-validator-monitor

78. How much SOL is required to run a validator?
    The amount varies, but 10 SOL+ is recommended for transaction fees.
79. How do you vote as a validator?
    Validators must create a vote account and submit votes to confirm transactions.
80. How do you update a Solana validator?

solana-install update

81. What is a delinquent validator in Solana?
    A validator that fails to produce blocks for several epochs.
82. How do you exit validator mode?

solana-validator exit