Agent Skills: MultiversX Blockchain Data — `self.blockchain()` API Reference

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 multiversx-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);