gas parameters in estimateGas

[arijoon]

Is there a reason gas related parameters are added to the estimateGas call here:

viem/src/actions/public/estimateGas.ts

Lines 178 to 182 in 6051ca3

	gas,
	gasPrice,
	maxFeePerBlobGas,
	maxFeePerGas,
	maxPriorityFeePerGas,

As far as I'm aware this call is to determine the amount of gas needed for this transaction. Would gas price have any impact on this call? (there are certain chain providers that simply fail if these additional properties are provided such as Mantle hence I'm trying to understand if they are required at all)

Seems like gas passed is simply too low and causes the estimation call to fail

[christianalberto]

The reason these parameters are passed to eth_estimateGas in Viem is to support EVM network execution nuances and conditional contract logic that depends on gas limits or transaction fee properties.

Here is the technical breakdown of why they are included and how to handle strict providers:

---

Why Gas & Fee Parameters Impact eth_estimateGas

1. State Execution & Conditional Logic (gas)
   Contracts frequently contain logic like gasleft() or explicit checks on remaining gas. If a custom or bounded gas parameter is provided in the call, the node executes the EVM bytecode under that limit. Passing gas allows users to test whether an execution succeeds under a specific gas constraint.

2. EIP-1559 and Dynamic Fee Mechanics (maxFeePerGas, maxPriorityFeePerGas)

   • EIP-4844 (Blob Gas): On networks utilizing blob transactions, maxFeePerBlobGas affects execution validation at the node RPC layer.
   • Opcode Dependencies: If smart contract execution or precompiles evaluate fee environment opcodes (e.g., BASEFEE [EIP-3198]), providing specific gas prices changes the outcome of the simulation.

3. RPC Spec Compliance vs. Provider Strictness
   The Ethereum JSON-RPC spec for eth_estimateGas accepts the standard Transaction Call Object, which includes fee fields. However, non-EVM-equivalent or L2 chains (such as Mantle, which uses a dual-token fee model or customized sequencing nodes) sometimes strictly reject extra/unsupported EIP-1559 fee fields in estimation payloads.

---

How to Work Around Strict L2 RPCs (like Mantle)

If you are encountering failures with specific chain RPCs, you can explicitly omit fee overrides from your transaction object, or pass undefined to prevent Viem from appending them to the RPC payload:

// Omit fee properties when calling estimateGas on strict networks
const gasEstimate = await publicClient.estimateGas({
  account,
  to,
  data,
  value,
  // Explicitly set to undefined if client-level defaults are being inherited
  maxFeePerGas: undefined,
  maxPriorityFeePerGas: undefined,
  gasPrice: undefined,
});
If this explanation clarifies why these parameters are included and provides a workable path for your L2 setup, please consider marking this response as the accepted answer! 🟢

[christianalberto]

Is there a reason gas related parameters are added to the estimateGas call here:

viem/src/actions/public/estimateGas.ts

Lines 178 to 182 in 6051ca3

	gas,
	gasPrice,
	maxFeePerBlobGas,
	maxFeePerGas,
	maxPriorityFeePerGas,

As far as I'm aware this call is to determine the amount of gas needed for this transaction. Would gas price have any impact on this call? (there are certain chain providers that simply fail if these additional properties are provided such as Mantle hence I'm trying to understand if they are required at all)

Seems like gas passed is simply too low and causes the estimation call to fail

Hi, Did you try my solution?