Simple Bank (Deposit + Withdraw) - Vyper Typing CST Test

Mode:

Duration:

balances: public(HashMap[address, uint256])

@payable
@external
def deposit():
	self.balances[msg.sender] += msg.value

@external
def withdraw(amount: uint256):
	assert self.balances[msg.sender] >= amount
	self.balances[msg.sender] -= amount
	send(msg.sender, amount)Coding works best on desktop or with an external keyboard.

Simple Bank (Deposit + Withdraw) — Vyper Code

A tiny bank contract allowing users to deposit and withdraw ETH.

balances: public(HashMap[address, uint256])

@payable
@external
def deposit():
	self.balances[msg.sender] += msg.value

@external
def withdraw(amount: uint256):
	assert self.balances[msg.sender] >= amount
	self.balances[msg.sender] -= amount
	send(msg.sender, amount)

Vyper Language Guide

Vyper is a security-focused, Python-like smart contract programming language for the Ethereum Virtual Machine (EVM). It emphasizes simplicity, readability, and auditability-making it ideal for high-assurance smart contracts.

Primary Use Cases

▸High-assurance smart contracts
▸DeFi protocols and vaults
▸Governance and treasury contracts
▸Security-audited financial logic
▸Minimalistic EVM dApps

Notable Features

▸Python-like syntax
▸Strong typing and safety checks
▸No modifiers -> predictable flow
▸No inheritance -> reduced complexity
▸Built-in overflow/underflow protection

Origin & Creator

Vyper was created by the Ethereum Foundation with contributions from Vitalik Buterin and the research team. It emerged around 2017 as a safer alternative to Solidity.

Industrial Note

Vyper is heavily used in high-stakes DeFi protocols, DAO governance, staking pools, and security-critical Ethereum contracts where simplicity and predictability matter more than feature richness.

Quick Explain

▸Vyper syntax is inspired by Python but intentionally limited for security.
▸It removes complex features to reduce attack surfaces (no modifiers, no inheritance).
▸Compiled directly to Ethereum Virtual Machine bytecode.
▸Designed for formal verification and auditing.
▸Used by DeFi, security-critical dApps, and DAO contracts.

Core Features

▸Events and logs
▸Interfaces
▸Custom structs
▸ABI compatibility with Solidity
▸EVM-level optimization

Learning Path

▸Learn Python basics
▸Understand EVM
▸Write minimal contracts
▸Master Vyper syntax
▸Learn auditing & gas optimization

Practical Examples

▸Minimal ERC-20 token
▸Treasury vault
▸DAO voting contract
▸Time-locked withdrawals
▸Staking and reward distribution

Comparisons

▸Vyper vs Solidity: Vyper is safer but has fewer features.
▸Vyper vs Rust-based languages: Vyper is simpler but less powerful.
▸Vyper vs Yul: Vyper is high-level; Yul is low-level.
▸Vyper vs Cairo: Cairo targets STARK VMs; Vyper targets EVM.
▸Vyper vs Move: Move is resource-based; Vyper is minimalistic.

Strengths

▸High security and predictability
▸Easy to read and audit
▸Minimal attack surface
▸Formally verifiable
▸Ideal for critical DeFi contracts

Limitations

▸No inheritance
▸No modifiers
▸Limited built-in tooling vs Solidity
▸Smaller ecosystem
▸Not ideal for highly complex contracts

When NOT to Use

▸Highly complex inheritance-based systems
▸Large modular contract architectures
▸Contracts requiring inline assembly
▸Custom low-level opcodes
▸Massive multi-file OOP-style programs

Cheat Sheet

▸@external -> public function
▸@view -> read-only
▸@payable -> accept ETH
▸event Transfer: ...
▸struct User: ...

FAQ

▸Is Vyper safer than Solidity?
▸Yes - by design.
▸Is Vyper widely used?
▸Yes in DeFi and audited contracts.
▸Does Vyper support inheritance?
▸No - intentionally removed.
▸Is Vyper slower?
▸No - often more gas-efficient.
▸Can Vyper and Solidity interact?
▸Yes - ABI compatible.

30-Day Skill Plan

▸Week 1: Vyper syntax
▸Week 2: Events + functions
▸Week 3: Interfaces + ABI
▸Week 4: Security testing
▸Week 5: Build DeFi primitives

Final Summary

▸Vyper is a secure, minimal, Python-like EVM language.
▸Ideal for high-assurance and audited smart contracts.
▸No modifiers, no inheritance, less complexity.
▸Used widely in DeFi, DAOs, and financial logic.
▸Perfect for developers who value safety + clarity.

Project Structure

▸contracts/ - Vyper source files
▸tests/ - Python tests
▸scripts/ - deployment scripts
▸interfaces/ - .vy interface files
▸build/ - compiled artifacts

Monetization

▸Develop audited contracts
▸Write DeFi Vyper modules
▸Offer security audits
▸Sell DAO governance templates
▸Consult enterprise blockchain teams

Productivity Tips

▸Keep contracts small
▸Use interfaces wisely
▸Rely on Brownie for testing
▸Simplify state transitions
▸Avoid unnecessary features

Basic Concepts

▸Functions with strict typing
▸Events for logging
▸State variables with visibility
▸Custom structs
▸Fallback and default functions

Official Docs

More Vyper Typing Exercises

Simple Counter Contract Owner-Only Storage ERC20-Like Token (Minimal)Timestamp Locker Simple Voting Whitelist Access Event Logger Immutable Config Simple Multiplier

Practice Other Languages

C React Python C++Rust TypeScript Kotlin PHP Java C#Ruby Mql Cql N1ql Cypher

balances: public(HashMap[address, uint256])

@payable
@external
def deposit():
self.balances[msg.sender] += msg.value

@external
def withdraw(amount: uint256):
assert self.balances[msg.sender] >= amount
self.balances[msg.sender] -= amount
send(msg.sender, amount)

Coding works best on desktop or with an external keyboard.

Simple Bank (Deposit + Withdraw) — Vyper Code

A tiny bank contract allowing users to deposit and withdraw ETH.

balances: public(HashMap[address, uint256]) @payable @external def deposit(): self.balances[msg.sender] += msg.value @external def withdraw(amount: uint256): assert self.balances[msg.sender] >= amount self.balances[msg.sender] -= amount send(msg.sender, amount)

Vyper Language Guide

Primary Use Cases

▸High-assurance smart contracts
▸DeFi protocols and vaults
▸Governance and treasury contracts
▸Security-audited financial logic
▸Minimalistic EVM dApps

Notable Features

▸Python-like syntax
▸Strong typing and safety checks
▸No modifiers -> predictable flow
▸No inheritance -> reduced complexity
▸Built-in overflow/underflow protection

Origin & Creator

Vyper was created by the Ethereum Foundation with contributions from Vitalik Buterin and the research team. It emerged around 2017 as a safer alternative to Solidity.

Industrial Note

Vyper is heavily used in high-stakes DeFi protocols, DAO governance, staking pools, and security-critical Ethereum contracts where simplicity and predictability matter more than feature richness.