Aptos Blockchain & Move Language Expert

Aptos is a Layer 1 blockchain with the Move programming language, designed for safe and scalable smart contracts.

When to Use

• Writing Move smart contracts
• Understanding Move type system (abilities, generics, resources)
• Using Aptos framework modules (coin, fungible_asset, object)
• Token standards (Coin, Fungible Asset, Digital Asset/NFT)
• Gas optimization and testing
• dApp integration with TypeScript SDK

Move Language Fundamentals

Abilities - Move's Core Feature

Every type has abilities that control what you can do with it:

// Resource that can be stored globally
struct Balance has key, store {
    coins: u64
}

// Value type that behaves like a primitive
struct Point has copy, drop, store {
    x: u64,
    y: u64
}

// No abilities = must be explicitly handled (hot potato)
struct Receipt {
    amount: u64
}

Generics and Phantom Types

// Type parameter with ability constraint
struct Box<T: store> has key {
    value: T
}

// Phantom type - zero runtime cost, type safety only
struct Coin<phantom CoinType> has store {
    value: u64
}

// Different types can't be mixed
let btc: Coin<BTC> = Coin { value: 100 };
let eth: Coin<ETH> = Coin { value: 50 };
// btc + eth → compile error!

Global Storage Operations

// Store resource at signer's address
public fun initialize(account: &signer) {
    move_to(account, MyResource { value: 0 });
}

// Read resource (requires acquires annotation)
public fun get_value(addr: address): u64 acquires MyResource {
    borrow_global<MyResource>(addr).value
}

// Modify resource
public fun set_value(addr: address, val: u64) acquires MyResource {
    borrow_global_mut<MyResource>(addr).value = val;
}

// Check existence
public fun exists_at(addr: address): bool {
    exists<MyResource>(addr)
}

// Remove and return resource
public fun destroy(addr: address): MyResource acquires MyResource {
    move_from<MyResource>(addr)
}

Signer - Authentication

use std::signer;

// Only the account owner can call this
public entry fun transfer(
    sender: &signer,
    recipient: address,
    amount: u64
) acquires Balance {
    let sender_addr = signer::address_of(sender);
    // sender proves ownership of sender_addr
}

Visibility Modifiers

module example {
    // Private (default) - only within module
    fun internal() { }

    // Public - callable from anywhere
    public fun library_fn() { }

    // Friend - only from declared friend modules
    public(friend) fun restricted() { }

    // Entry - transaction entry point
    public entry fun user_action(account: &signer) { }
}

Aptos Framework (0x1)

Core Modules

Coin Standard (0x1::coin)

use aptos_framework::coin;

// Register to receive a coin type
public entry fun register<CoinType>(account: &signer) {
    coin::register<CoinType>(account);
}

// Transfer coins
public entry fun transfer<CoinType>(
    from: &signer,
    to: address,
    amount: u64
) {
    coin::transfer<CoinType>(from, to, amount);
}

// Check balance
public fun balance<CoinType>(addr: address): u64 {
    coin::balance<CoinType>(addr)
}

Fungible Asset Standard (0x1::fungible_asset)

Modern, flexible token standard:

use aptos_framework::fungible_asset::{Self, FungibleAsset, Metadata};
use aptos_framework::primary_fungible_store;

// Create fungible asset metadata
public fun create_fa(creator: &signer): Object<Metadata> {
    let constructor_ref = object::create_named_object(creator, b"MY_FA");
    
    primary_fungible_store::create_primary_store_enabled_fungible_asset(
        &constructor_ref,
        option::none(), // max supply
        utf8(b"My Token"),
        utf8(b"MTK"),
        8, // decimals
        utf8(b"https://example.com/icon.png"),
        utf8(b"https://example.com"),
    );
    
    object::object_from_constructor_ref(&constructor_ref)
}

// Transfer FA
public entry fun transfer_fa(
    sender: &signer,
    metadata: Object<Metadata>,
    recipient: address,
    amount: u64
) {
    primary_fungible_store::transfer(sender, metadata, recipient, amount);
}

Object Model (0x1::object)

Composable, transferable objects:

use aptos_framework::object::{Self, Object, ConstructorRef};

struct MyObject has key {
    value: u64
}

// Create object
public 

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