HDP Capabilities and API Surface

HDP exposes four capability groups in your Cairo module:

hdp.evm for EVM data
hdp.starknet for Starknet data
hdp.injected_state for injected trie state
hdp.unconstrained helpers for unconstrained reads

It also exposes execute_eth_call for provable EVM contract calls at a chosen historical block.

HDP object in your module

pub struct HDP {
    pub evm: EvmMemorizer,
    pub starknet: StarknetMemorizer,
    pub injected_state: InjectedStateMemorizer,
    pub unconstrained: UnconstrainedMemorizer,
}

1) `hdp.evm` (EVM memorizer)

Reads verified EVM data for a specific (chain_id, block_number, ...) key. Chain constants:

ETHEREUM_MAINNET_CHAIN_ID
ETHEREUM_TESTNET_CHAIN_ID
OPTIMISM_MAINNET_CHAIN_ID
OPTIMISM_TESTNET_CHAIN_ID

Header fields

Input key for all methods below: HeaderKey { chain_id, block_number }

API	Output	What it gives you
`header_get_parent`	`u256`	Parent block hash of the block header
`header_get_uncle`	`u256`	Uncle/ommer hash field from the header
`header_get_coinbase`	`u256`	Block proposer (beneficiary) address
`header_get_state_root`	`u256`	Global EVM state root for that block
`header_get_transaction_root`	`u256`	Transaction trie root for that block
`header_get_receipt_root`	`u256`	Receipt trie root for that block
`header_get_bloom`	`ByteArray`	Header bloom filter for event prefiltering
`header_get_difficulty`	`u256`	Block difficulty field
`header_get_number`	`u256`	Block number from the header
`header_get_gas_limit`	`u256`	Block gas limit
`header_get_gas_used`	`u256`	Total gas used in that block
`header_get_timestamp`	`u256`	Block timestamp
`header_get_mix_hash`	`u256`	Header mix hash field
`header_get_nonce`	`u256`	Header nonce field
`header_get_base_fee_per_gas`	`u256`	EIP-1559 base fee for the block
`header_get_blob_gas_used`	`u256`	Blob gas used (EIP-4844 field)
`header_get_excess_blob_gas`	`u256`	Excess blob gas (EIP-4844 field)
`header_get_requests_hash`	`u256`	Requests hash field from the header

Account fields

Input key for all methods below: AccountKey { chain_id, block_number, address }

API	Output	What it gives you
`account_get_nonce`	`u256`	Account nonce at the selected block
`account_get_balance`	`u256`	Account ETH balance at the selected block
`account_get_state_root`	`u256`	Account storage root
`account_get_code_hash`	`u256`	Account bytecode hash

Storage

API	Input	Output	What it gives you
`storage_get_slot`	`StorageKey { chain_id, block_number, address, storage_slot }`	`u256`	Value of a specific storage slot for a contract at that block

Block transactions

Input key for all methods below: BlockTxKey { chain_id, block_number, transaction_index }

API	Output	What it gives you
`block_tx_get_nonce`	`u256`	Nonce of a transaction by block/index
`block_tx_get_gas_price`	`u256`	Legacy gas price of the transaction
`block_tx_get_gas_limit`	`u256`	Gas limit set on the transaction
`block_tx_get_receiver`	`u256`	Recipient address (`to`)
`block_tx_get_value`	`u256`	Native token value transferred
`block_tx_get_v`	`u256`	Signature `v` component
`block_tx_get_r`	`u256`	Signature `r` component
`block_tx_get_s`	`u256`	Signature `s` component
`block_tx_get_chain_id`	`u256`	Transaction chain id
`block_tx_get_max_fee_per_gas`	`u256`	EIP-1559 max fee per gas
`block_tx_get_max_priority_fee_per_gas`	`u256`	EIP-1559 priority fee
`block_tx_get_max_fee_per_blob_gas`	`u256`	EIP-4844 max fee per blob gas
`block_tx_get_tx_type`	`u256`	Transaction type
`block_tx_get_sender`	`u256`	Sender address (`from`)
`block_tx_get_hash`	`u256`	Transaction hash

Block receipts

Input key for all methods below: BlockReceiptKey { chain_id, block_number, transaction_index }

API	Output	What it gives you
`block_receipt_get_status`	`u256`	Execution status of a transaction receipt
`block_receipt_get_cumulative_gas_used`	`u256`	Cumulative gas used at this receipt index
`block_receipt_get_bloom`	`ByteArray`	Receipt bloom for event filtering

Logs

Input key for all methods below: LogKey { chain_id, block_number, transaction_index, log_index }

API	Output	What it gives you
`log_get_address`	`u256`	Contract address that emitted the log
`log_get_topic0`	`u256`	First topic (usually event signature hash)
`log_get_topic1`	`u256`	Second indexed topic
`log_get_topic2`	`u256`	Third indexed topic
`log_get_topic3`	`u256`	Fourth indexed topic
`log_get_topic4`	`u256`	Fifth topic when present
`log_get_data`	`Array<u128>`	Unindexed event data payload

2) `hdp.starknet` (Starknet memorizer)

Reads verified Starknet data for a specific (chain_id, block_number, ...) key. Chain constants:

STARKNET_MAINNET_CHAIN_ID
STARKNET_TESTNET_CHAIN_ID

Header fields

Input key for all methods below: HeaderKey { chain_id, block_number }

API	Output	What it gives you
`header_get_block_number`	`felt252`	Starknet block number
`header_get_state_root`	`felt252`	Global Starknet state root
`header_get_sequencer_address`	`felt252`	Sequencer address for that block
`header_get_block_timestamp`	`felt252`	Block timestamp
`header_get_transaction_count`	`felt252`	Number of transactions in the block
`header_get_transaction_commitment`	`felt252`	Transaction commitment value
`header_get_event_count`	`felt252`	Number of events in the block
`header_get_event_commitment`	`felt252`	Event commitment value
`header_get_parent_block_hash`	`felt252`	Parent block hash
`header_get_state_diff_commitment`	`felt252`	State diff commitment
`header_get_state_diff_length`	`felt252`	State diff length
`header_get_l1_gas_price_in_wei`	`felt252`	L1 gas price (wei unit field)
`header_get_l1_gas_price_in_fri`	`felt252`	L1 gas price (fri unit field)
`header_get_l1_data_gas_price_in_wei`	`felt252`	L1 data gas price (wei unit field)
`header_get_l1_data_gas_price_in_fri`	`felt252`	L1 data gas price (fri unit field)
`header_get_receipts_commitment`	`felt252`	Receipts commitment value
`header_get_l1_data_mode`	`felt252`	L1 data availability mode field
`header_get_protocol_version`	`felt252`	Protocol version field

Storage

API	Input	Output	What it gives you
`storage_get_slot`	`StorageKey { chain_id, block_number, address, storage_slot }`	`felt252`	Value of a specific Starknet storage slot at that block

3) `hdp.injected_state` (InjectedState memorizer)

Works with labeled trie-like injected state you provide for a run.

API	Input	Output	What it gives you
`read_injected_state_trie_root(label)`	`label: felt252`	`Option<felt252>`	Current root for the labeled injected trie
`read_key(label, key)`	`label: felt252, key: felt252`	`Option<felt252>`	Value for a key in the labeled injected trie
`write_key(label, key, value)`	`label: felt252, key: felt252, value: felt252`	`felt252`	Writes a value and returns the updated trie root

4) `hdp.unconstrained` / unconstrained helpers

API	Input	Output	What it gives you
`evm_account_get_bytecode(key)`	`AccountKey { chain_id, block_number, address }`	`ByteCode`	Contract bytecode for an EVM account at a chosen block

5) `execute_eth_call` (provable EVM call)

execute_eth_call lets you perform a provable EVM contract call at a chosen historical block.

Item	What it means
Input `HDP`	Access to HDP-backed verified chain state
Input `TimeAndSpace { chain_id, block_number }`	Selects which chain and historical block to execute against
Input `sender`	Caller address context for the call
Input `target`	Contract being called
Input `calldata`	ABI-encoded function selector + arguments
Output `success`	Whether the call execution succeeded
Output `return_data`	Raw return bytes from the contract
Output `gas_used`	Gas consumed by the call execution
Output `state`	Post-call execution state object

See the dedicated page for details and patterns:

Provable EVM Contract Calls (execute_eth_call)

Data Processor (HDP)

AI Skill

Setup and Run

Core Concepts

Guides and Examples

Reference

HDP object in your module

1) `hdp.evm` (EVM memorizer)

Header fields

Account fields

Storage

Block transactions

Block receipts

Logs

2) `hdp.starknet` (Starknet memorizer)

Header fields

Storage

3) `hdp.injected_state` (InjectedState memorizer)

4) `hdp.unconstrained` / unconstrained helpers

5) `execute_eth_call` (provable EVM call)

Data Processor (HDP)

AI Skill

Setup and Run

Core Concepts

Guides and Examples

Reference

​HDP object in your module

​1) hdp.evm (EVM memorizer)

​Header fields

​Account fields

​Storage

​Block transactions

​Block receipts

​Logs

​2) hdp.starknet (Starknet memorizer)

​Header fields

​Storage

​3) hdp.injected_state (InjectedState memorizer)

​4) hdp.unconstrained / unconstrained helpers

​5) execute_eth_call (provable EVM call)

HDP object in your module

1) `hdp.evm` (EVM memorizer)

Header fields

Account fields

Storage

Block transactions

Block receipts

Logs

2) `hdp.starknet` (Starknet memorizer)

Header fields

Storage

3) `hdp.injected_state` (InjectedState memorizer)

4) `hdp.unconstrained` / unconstrained helpers

5) `execute_eth_call` (provable EVM call)