Collators aggregate parachain transactions block candidates and producing state transition proofs for validators based on those blocks.

Heima is a specialized identity and data verification blockchain powered by Polkadot Relay chain.

HEI holders own and govern the protocol. Heima’s investors include LD Capital, Digital Renaissance, Signum Capital, and others.

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Heima

# Heima Fees Methodology

## 1. Overview

The Heima fees metric measures the total transaction fees paid by users across both the native Heima parachain (L1) and the Heima EVM layer (L2). This metric captures the economic activity and network usage of the Heima protocol by aggregating all user-paid transaction costs, including base fees and tips, converted to USD values.

The calculation combines direct fee events from the native parachain with derived fees from EVM layer transactions, using sophisticated account mapping to ensure accurate attribution of costs to legitimate user activities.

## 2. Data sources

- **Heima parachain events**: System and transaction events including `NewAccount`, `TransactionFeePaid`, `Executed`, `Withdraw`, and `Deposit` events from various pallets (system, evm, ethereum, balances)
- **Blockchain transaction data**: Heima parachain block timestamps, transaction hashes, and extrinsic identifiers for temporal and transactional context
- **External price data**: End-of-day price feeds from CoinGecko for the Heima token to enable USD conversion
- **Account mapping data**: Substrate SS58 addresses and derived EVM addresses for cross-layer transaction attribution

## 3. Step-by-step calculation

### Component A: L1 native chain fees
- **Purpose**: Captures transaction fees paid on the native Heima parachain
- **Logic**: Extracts `TransactionFeePaid` events from successful transactions in the Heima blockchain events. Each event contains the base transaction `amount` and optional `tip` paid by users. The raw values are converted from 18-decimal blockchain units to standard token amounts by dividing by 1e18. Only transactions marked as successful are included to avoid counting failed transaction attempts.
- **Key fields**: `block_timestamp` for temporal aggregation, `amount` and `tip` for fee calculation, `extrinsic_hash` for transaction identification, `success` flag for filtering

### Component B: L2 EVM layer fees  
- **Purpose**: Derives transaction fees from balance changes in the Heima EVM layer
- **Logic**: Identifies EVM transactions through `Executed` events in the evm pallet, then matches these to corresponding balance `Withdraw` and `Deposit` events in the ethereum pallet. Uses account mapping to ensure the balance change signer matches the EVM transaction executor, preventing capture of system-level operations. Withdrawal amounts represent fees paid, while deposits represent refunds, so the net amount (withdraw - deposit) gives the actual fee per transaction.
- **Key fields**: `extrinsic_id` for linking EVM executions to balance changes, `transaction_fee` from balance event amounts, `signer_address` for account matching

### Component C: Account mapping
- **Purpose**: Creates mapping between Substrate parachain addresses and EVM addresses for cross-layer transaction attribution
- **Logic**: Extracts parachain accounts from system `NewAccount` events, decodes SS58-formatted addresses to hexadecimal format using base58 decoding, then derives corresponding EVM addresses using the standard keccak256 hash function with "evm:" prefix (H160::from(keccak256("evm:" + substrate_account)[12..32])). This mapping ensures L2 fee attribution only includes legitimate user transactions where the same account initiated both the EVM execution and the balance changes.
- **Key fields**: `parachain_account` as the original substrate address, `evm_account` as the derived EVM address

### Final aggregation
- **Combining components**: L1 and L2 fees are summed separately by day, then combined using a union operation to create a unified daily fee total for the Heima protocol
- **Currency conversion**: Daily fee amounts in native Heima tokens are converted to USD using end-of-day CoinGecko price feeds for the Heima token, applying the `convert_usd_cg` macro with coingecko_id 'heima'
- **Time aggregation**: All timestamps are truncated to daily boundaries using `timestamp_trunc(timestamp, day)` to ensure consistent daily aggregation across both L1 and L2 components
- **Final calculation**: The metric represents the sum of (L1_amount + L1_tip + L2_net_fees) × Heima_USD_price for each day, standardized through the `finalize_metric_fees` macro with forward-fill strategy for missing days

*This methodology was automatically generated by Token Terminal's methodology analyzer.*

Total value users pay to use a protocol (gross fees, user-paid fees).

HeimaHEI

Fees

Fees

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