mvx-blockchain-data

name	mvx-blockchain-data
description	Read on-chain state in MultiversX smart contracts. Use when accessing caller info, account balances, block timestamps, ESDT token metadata, local roles, code metadata, or any data from self.blockchain().

MultiversX Blockchain Data — self.blockchain() API Reference

Complete reference for reading on-chain state in MultiversX smart contracts (SDK v0.64+).

Caller & Account Info

Method	Returns	Description
.get_caller()	ManagedAddress	Address that initiated the current call
.get_sc_address()	ManagedAddress	This contract's own address
.get_owner_address()	ManagedAddress	Contract owner address
.check_caller_is_owner()	()	Panics if caller != owner. Equivalent to #[only_owner].
.check_caller_is_user_account()	()	Panics if caller is a smart contract (not an EOA).
.is_smart_contract(address)	bool	Check if an address is a smart contract
.get_shard_of_address(address)	u32	Get shard ID for an address

// Owner-only guard (manual alternative to #[only_owner])
self.blockchain().check_caller_is_owner();

// Prevent contract-to-contract calls (anti-flash-loan)
self.blockchain().check_caller_is_user_account();

// Check if target is a SC before sending
let is_sc = self.blockchain().is_smart_contract(&target);

Balances

Method	Returns	Description
.get_balance(address)	BigUint	EGLD balance of any address
.get_sc_balance(token_id, nonce)	BigUint	This contract's balance of any token (EGLD or ESDT). token_id is impl AsRef<TokenId>.
.get_esdt_balance(address, token_id, nonce)	BigUint	ESDT balance of any address. token_id is &EsdtTokenIdentifier.

// Check own EGLD balance
let egld = self.blockchain().get_balance(&self.blockchain().get_sc_address());

// Check own ESDT balance (simpler via get_sc_balance)
let balance = self.blockchain().get_sc_balance(&my_token_id, 0u64);

Block Info

Current Block

Method	Returns	Description
.get_block_timestamp_seconds()	TimestampSeconds	Block timestamp in seconds (v0.63+)
.get_block_timestamp_millis()	TimestampMillis	Block timestamp in milliseconds (v0.63+)
.get_block_nonce()	u64	Block nonce (height)
.get_block_round()	u64	Block round
.get_block_epoch()	u64	Current epoch
.get_block_round_time_millis()	DurationMillis	Round duration in ms (v0.63+)
.get_block_random_seed()	ManagedByteArray<48>	48-byte random seed

Previous Block

Method	Returns	Description
.get_prev_block_timestamp_seconds()	TimestampSeconds	Previous block timestamp (seconds)
.get_prev_block_timestamp_millis()	TimestampMillis	Previous block timestamp (ms)
.get_prev_block_nonce()	u64	Previous block nonce
.get_prev_block_round()	u64	Previous block round
.get_prev_block_epoch()	u64	Previous epoch
.get_prev_block_random_seed()	ManagedByteArray<48>	Previous block random seed

Epoch Start Info

Method	Returns	Description
.get_epoch_start_block_timestamp_millis()	TimestampMillis	When current epoch started
.get_epoch_start_block_nonce()	u64	Block nonce at epoch start
.get_epoch_start_block_round()	u64	Block round at epoch start

Deprecated Timestamp Methods (Do NOT Use)

Deprecated	Replacement	Since
.get_block_timestamp()	.get_block_timestamp_seconds()	v0.63
.get_block_timestamp_ms()	.get_block_timestamp_millis()	v0.63
.get_prev_block_timestamp()	.get_prev_block_timestamp_seconds()	v0.63
.get_prev_block_timestamp_ms()	.get_prev_block_timestamp_millis()	v0.63
.get_block_round_time_ms()	.get_block_round_time_millis()	v0.63
.epoch_start_block_timestamp_ms()	.get_epoch_start_block_timestamp_millis()	v0.63
.epoch_start_block_timestamp_millis()	.get_epoch_start_block_timestamp_millis()	v0.63.1
.epoch_start_block_nonce()	.get_epoch_start_block_nonce()	v0.63.1
.epoch_start_block_round()	.get_epoch_start_block_round()	v0.63.1

Transaction Info

Method	Returns	Description
.get_tx_hash()	ManagedByteArray<32>	Current transaction hash
.get_gas_left()	u64	Remaining gas
.get_state_root_hash()	ManagedByteArray<32>	State root hash

ESDT Token Metadata

Method	Returns	Description
.get_esdt_token_data(address, token_id, nonce)	EsdtTokenData	Full token data (amount, attributes, creator, royalties, URIs, etc.)
.get_esdt_token_type(address, token_id, nonce)	EsdtTokenType	Token type enum (Fungible, NonFungible, SemiFungible, Meta)
.get_token_attributes::<T>(token_id, nonce)	T: TopDecode	Deserialized NFT/SFT attributes from this contract's account
.get_current_esdt_nft_nonce(address, token_id)	u64	Last minted nonce for a token on an address

// EsdtTokenData fields:
pub struct EsdtTokenData<M: ManagedTypeApi> {
    pub token_type: EsdtTokenType,
    pub amount: BigUint<M>,
    pub frozen: bool,
    pub hash: ManagedBuffer<M>,
    pub name: ManagedBuffer<M>,
    pub attributes: ManagedBuffer<M>,  // raw bytes — use get_token_attributes for typed
    pub creator: ManagedAddress<M>,
    pub royalties: BigUint<M>,         // 0-10000 (basis points)
    pub uris: ManagedVec<M, ManagedBuffer<M>>,
}

// Read NFT attributes as a typed struct
#[derive(TopDecode)]
struct MyNftAttributes {
    level: u8,
    power: u64,
}

let attrs: MyNftAttributes = self.blockchain()
    .get_token_attributes::<MyNftAttributes>(&nft_token_id, nft_nonce);

ESDT Status & Roles

Method	Returns	Description
.is_esdt_frozen(address, token_id, nonce)	bool	Whether token is frozen for this address
.is_esdt_paused(token_id)	bool	Whether token transfers are globally paused
.is_esdt_limited_transfer(token_id)	bool	Whether token has limited transfer enabled
.get_esdt_local_roles(token_id)	EsdtLocalRoleFlags	Bitmask of roles this contract has for the token

// Check roles before minting
let roles = self.blockchain().get_esdt_local_roles(&token_id);
require!(
    roles.has_role(&EsdtLocalRole::NftCreate),
    "Contract lacks NftCreate role"
);

Code Inspection

Method	Returns	Description
.get_code_metadata(address)	CodeMetadata	Contract code metadata (upgradeable, readable, payable flags)
.get_code_hash(address)	ManagedBuffer	Hash of contract WASM code
.is_builtin_function(name)	bool	Whether a function name is a protocol built-in

Native Token

Method	Returns	Description
.get_native_token()	ManagedRef<TokenId>	Returns EGLD-000000 as a TokenId
.is_native_token(token_id)	bool	Checks if a TokenId is EGLD-000000

Validators

Method	Returns	Description
.get_cumulated_validator_rewards()	BigUint	Validator rewards accrued to this contract

Back-Transfers (After Cross-Contract Calls)

Method	Returns	Description
.get_back_transfers()	BackTransfers	All tokens returned from a sync/async call
.reset_back_transfers()	()	Clears current back-transfers (prevents double-reading)

See the mvx-cross-contract-calls skill for full back-transfer patterns.

Common Patterns

Time-Based Logic

let now = self.blockchain().get_block_timestamp_seconds();
let deadline = self.deadline().get();
require!(now < deadline, "Deadline passed");

Shard-Aware Operations

let caller_shard = self.blockchain().get_shard_of_address(
    &self.blockchain().get_caller()
);
let sc_shard = self.blockchain().get_shard_of_address(
    &self.blockchain().get_sc_address()
);
let same_shard = caller_shard == sc_shard;
// If same shard, can use sync calls; otherwise need async

Token Property Validation

fn validate_nft(&self, token_id: &EsdtTokenIdentifier, nonce: u64) {
    let sc_addr = self.blockchain().get_sc_address();
    let data = self.blockchain().get_esdt_token_data(&sc_addr, token_id, nonce);
    require!(data.amount > 0u64, "NFT not owned");
    require!(!data.frozen, "Token is frozen");
}

Balance Check Before Transfer

let sc_balance = self.blockchain().get_sc_balance(&token_id, 0u64);
require!(sc_balance >= amount, "Insufficient contract balance");
self.tx().to(&recipient).esdt((token_id, 0u64, amount)).transfer();

Anti-Patterns

// BAD: Using deprecated get_block_timestamp() — returns raw u64
let ts = self.blockchain().get_block_timestamp();

// GOOD: Use typed timestamp (v0.63+)
let ts = self.blockchain().get_block_timestamp_seconds();

// BAD: Storing raw u64 timestamps, mixing seconds/millis
self.last_action().set(self.blockchain().get_block_timestamp_millis().as_u64_millis());

// GOOD: Store typed timestamps
self.last_action().set(self.blockchain().get_block_timestamp_seconds());

// BAD: get_balance to check own EGLD — requires passing own address
let bal = self.blockchain().get_balance(&self.blockchain().get_sc_address());

// GOOD: Use get_sc_balance which handles EGLD via native token detection
let bal = self.blockchain().get_sc_balance(&self.blockchain().get_native_token(), 0u64);