Fee model

Overview

Like other rollups (e.g., ZKsync), Via Network must cover the cost of publishing transactions from L2 back to L1. Because of this, fees on Via Network depend on:

• Layer‑1 gas prices

• DA layer gas cost parameters

• L2 minimum gas price parameters

These combine to form an L2 gas price that balances fair fee pricing and operational cost recovery.

The core output of this model is a set of values called the batch fee inputs, including:

• l1_gas_price: the scaled L1 gas price

• fair_l2_gas_price: the L2 gas price that transactions must pay

• fair_pubdata_price: the scaled pubdata price for publishing data

These values are passed to the rest of the system to determine final transaction fees.

Fee Model Structure

The Via Network fee model is composed of three main pieces:

1. Fee parameter provider – supplies real‑time L1 price information.

2. Batch fee input calculator – computes the fair L2 gas price and pubdata price.

3. Clipping logic – enforces operational caps to ensure continuity GitHub

Term	Meaning
L1 Gas Price	Cost (in base tokens) to publish on the Layer‑1 chain (scaled).
Fair L2 Gas Price	A baseline gas price that L2 transactions must meet, covering overhead and minimum thresholds.
Fair Pubdata Price	A price for bytes of pubdata, tied to the base L1 price.

Deriving the Fee

Get L1 Prices

Via’s fee model starts by querying the Bitcoin L1 price from an external provider for:

• l1_gas_price: the L1 gas price history

• l1_pubdata_price: the estimated cost per pubdata unit

These come from an implementation of ViaBaseTokenRatioProvider.

Compute Fair L2 Gas Price

The fair L2 gas price is computed based on batch overheads and a minimum L2 gas price provided in the configuration. The formula is:

let mut fair_l2_gas_price = gas_price_satoshi + config.minimal_l2_gas_price;

Where:

• batch_overhead_l1_gas: L1 gas cost per batch (operational overhead)

• config.max_gas_per_batch: max gas units per batch

• config.minimal_l2_gas_price: minimum allowable L2 gas price

This produces a fair L2 gas price that covers overheads and respects the configured minimum

Pubdata Price

Via uses the scaled L1 pubdata price parameter (relatively constant cost on DA layer) directly as the fair pubdata price:

let mut fair_pubdata_price = scaled_l1_pubdata_price;

This price roughly tracks how much it costs to post data to DA layer(Celestia).

When submitting a transaction, your effective gas cost will depend on:

• Current L1 gas price (from real feeds)

• Pubdata pricing tied to DA pubdata cost

• L2 minimum gas price.

These combine to give a per‑unit L2 gas price for your transaction, ensuring both fair pricing and operational cost coverage.

MAX_TRANSACTION_GAS_LIMIT

A recommended maximal amount of gas that a transaction can spend on computation is MAX_TRANSACTION_GAS_LIMIT=1125899906842624.

Reference:

• For the full Rust source, see: Github

• Zksync fee model