Learn Vyper - 10 Code Examples & CST Typing Practice Test

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.

View all 10 Vyper code examples →

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

Learn VYPER with Real Code Examples

Updated Nov 25, 2025

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Code Sample Descriptions

Simple Counter Contract

count: public(uint256)

@external
def __init__():
    self.count = 0

@external
def increment():
    self.count += 1

@external
def reset():
    self.count = 0

A minimal counter smart contract using Vyper with increment and reset functions.

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Owner-Only Storage

owner: public(address)
message: public(String[100])

@external
def __init__():
    self.owner = msg.sender
    self.message = ""

@external
def set_message(new_message: String[100]):
    assert msg.sender == self.owner
    self.message = new_message

A contract where only the owner can update a stored message.

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Simple Bank (Deposit + Withdraw)

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)

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

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ERC20-Like Token (Minimal)

total_supply: public(uint256)
balances: public(HashMap[address, uint256])

@external
def __init__(_s: uint256):
    self.total_supply = _s
    self.balances[msg.sender] = _s

@external
def transfer(to: address, amount: uint256):
    assert self.balances[msg.sender] >= amount
    self.balances[msg.sender] -= amount
    self.balances[to] += amount

A simplified ERC20-style token for demonstration purposes.

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Timestamp Locker

unlock_time: public(uint256)

@payable
@external
def __init__(_unlock: uint256):
    self.unlock_time = _unlock

@external
def withdraw():
    assert block.timestamp >= self.unlock_time
    send(msg.sender, self.balance)

A simple timelock contract where ETH can only be withdrawn after a specific timestamp.

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Simple Voting

yes: public(uint256)
no: public(uint256)

@external
def vote(choice: bool):
    if choice:
        self.yes += 1
    else:
        self.no += 1

A tiny voting system with yes/no votes.

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Whitelist Access

owner: public(address)
whitelist: public(HashMap[address, bool])

@external
def __init__():
    self.owner = msg.sender

@external
def add_user(user: address):
    assert msg.sender == self.owner
    self.whitelist[user] = True

@external
def restricted_action():
    assert self.whitelist[msg.sender] == True

A contract that allows only whitelisted addresses to perform an action.

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Event Logger

event Log:
    creator: address
    message: String[100]

@external
def fire(msg: String[100]):
    log Log(msg.sender, msg)

A simple example of Vyper events.

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Immutable Config

CONFIG: immutable(uint256)

@external
def __init__(v: uint256):
    CONFIG = v

@external
def get_config() -> uint256:
    return CONFIG

Shows how to use `immutable` variables in Vyper.

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Simple Multiplier

factor: public(uint256)

@external
def __init__(_factor: uint256):
    self.factor = _factor

@external
def multiply(x: uint256) -> uint256:
    return x * self.factor

A utility contract that multiplies a number by a constant stored in the contract.

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Frequently Asked Questions about Vyper

What is Vyper?

What are the primary use cases for Vyper?

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

What are the strengths of Vyper?

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

What are the limitations of Vyper?

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

How can I practice Vyper typing speed?

CodeSpeedTest offers 10+ real Vyper code examples for typing practice. You can measure your WPM, track accuracy, and improve your coding speed with guided exercises.

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Code Sample Descriptions

Simple Counter Contract

count: public(uint256)

@external
def __init__():
    self.count = 0

@external
def increment():
    self.count += 1

@external
def reset():
    self.count = 0

A minimal counter smart contract using Vyper with increment and reset functions.

Let’s Try →

Owner-Only Storage

owner: public(address)
message: public(String[100])

@external
def __init__():
    self.owner = msg.sender
    self.message = ""

@external
def set_message(new_message: String[100]):
    assert msg.sender == self.owner
    self.message = new_message

A contract where only the owner can update a stored message.

Let’s Try →

Simple Bank (Deposit + Withdraw)

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)

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

Let’s Try →

ERC20-Like Token (Minimal)

total_supply: public(uint256)
balances: public(HashMap[address, uint256])

@external
def __init__(_s: uint256):
    self.total_supply = _s
    self.balances[msg.sender] = _s

@external
def transfer(to: address, amount: uint256):
    assert self.balances[msg.sender] >= amount
    self.balances[msg.sender] -= amount
    self.balances[to] += amount

A simplified ERC20-style token for demonstration purposes.

Let’s Try →

Timestamp Locker

unlock_time: public(uint256)

@payable
@external
def __init__(_unlock: uint256):
    self.unlock_time = _unlock

@external
def withdraw():
    assert block.timestamp >= self.unlock_time
    send(msg.sender, self.balance)

A simple timelock contract where ETH can only be withdrawn after a specific timestamp.

Let’s Try →

Simple Voting

yes: public(uint256)
no: public(uint256)

@external
def vote(choice: bool):
    if choice:
        self.yes += 1
    else:
        self.no += 1

A tiny voting system with yes/no votes.

Let’s Try →

Whitelist Access

owner: public(address)
whitelist: public(HashMap[address, bool])

@external
def __init__():
    self.owner = msg.sender

@external
def add_user(user: address):
    assert msg.sender == self.owner
    self.whitelist[user] = True

@external
def restricted_action():
    assert self.whitelist[msg.sender] == True

A contract that allows only whitelisted addresses to perform an action.

Let’s Try →

Event Logger

event Log:
    creator: address
    message: String[100]

@external
def fire(msg: String[100]):
    log Log(msg.sender, msg)

A simple example of Vyper events.

Let’s Try →

Immutable Config

CONFIG: immutable(uint256)

@external
def __init__(v: uint256):
    CONFIG = v

@external
def get_config() -> uint256:
    return CONFIG

Shows how to use `immutable` variables in Vyper.

Let’s Try →

Simple Multiplier

factor: public(uint256)

@external
def __init__(_factor: uint256):
    self.factor = _factor

@external
def multiply(x: uint256) -> uint256:
    return x * self.factor

A utility contract that multiplies a number by a constant stored in the contract.

Let’s Try →

Frequently Asked Questions about Vyper

What is Vyper?

What are the primary use cases for Vyper?

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

What are the strengths of Vyper?

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

What are the limitations of Vyper?

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

How can I practice Vyper typing speed?

CodeSpeedTest offers 10+ real Vyper code examples for typing practice. You can measure your WPM, track accuracy, and improve your coding speed with guided exercises.