Derived max fee per gas {max_fee} wei exceeds ceiling {max_f

Error message

Derived max fee per gas {max_fee} wei exceeds ceiling {max_fee_per_gas_wei} wei

What it means

derive_fees computes a max fee per gas from a buffered base fee plus a priority fee and enforces a configured ceiling max_fee_per_gas_wei. It bails when the derived max fee exceeds that ceiling, so callers never sign a transaction whose fee cap exceeds policy. The priority fee is returned unchanged alongside.

Source

Thrown at crates/adapters/blockchain/src/execution/transaction.rs:368

///
/// # Errors
///
/// Returns an error if the derived max fee exceeds `max_fee_per_gas_wei` or the arithmetic
/// overflows.
pub fn derive_fees(
    base_fee_per_gas_wei: u128,
    priority_fee_per_gas_wei: u128,
    base_fee_buffer_bps: u32,
    max_fee_per_gas_wei: u128,
) -> anyhow::Result<(u128, u128)> {
    let max_fee = compute_max_fee(
        base_fee_per_gas_wei,
        priority_fee_per_gas_wei,
        base_fee_buffer_bps,
    )?;

    if max_fee > max_fee_per_gas_wei {
        anyhow::bail!(
            "Derived max fee per gas {max_fee} wei exceeds ceiling {max_fee_per_gas_wei} wei"
        );
    }

    Ok((max_fee, priority_fee_per_gas_wei))
}

/// Computes the EIP-1559 max fee per gas: the base fee with `base_fee_buffer_bps` applied
/// plus the priority fee, without applying any ceiling.
///
/// # Errors
///
/// Returns an error if the arithmetic overflows.
pub fn compute_max_fee(
    base_fee_per_gas_wei: u128,
    priority_fee_per_gas_wei: u128,
    base_fee_buffer_bps: u32,
) -> anyhow::Result<u128> {

View on GitHub (pinned to 18893faf8b)

Solutions

Raise the max_fee_per_gas_wei ceiling to accommodate current network base fee plus buffer and priority fee.
Reduce base_fee_buffer_bps or the priority fee so the derived max fee fits under the ceiling.
Refresh base fee data from the latest block — a stale/spiked base_fee_per_gas_wei input may be the cause.
If the ceiling is a hard policy limit, delay or skip the transaction until base fee falls rather than raising the ceiling.

Example fix

// before
let (max_fee, tip) = derive_fees(50_000_000_000, 2_000_000_000, 2000, 40_000_000_000)?; // derived > 40 gwei ceiling
// after
let (max_fee, tip) = derive_fees(50_000_000_000, 2_000_000_000, 2000, 75_000_000_000)?; // ceiling raised

Defensive patterns

Strategy: validation

Validate before calling

fn fees_within_ceiling(base_fee: u128, tip: u128, bps: u32, ceiling: u128) -> bool {
    let max_fee = base_fee * (10_000 + bps as u128) / 10_000 + tip;
    max_fee <= ceiling
}
// verify config before calling derive_fees

Try / catch

match derive_fees(base_fee, tip, bps, ceiling) {
    Err(e) if e.to_string().contains("exceeds ceiling") => /* defer tx or raise ceiling per policy */,
    Err(e) => return Err(e),
    Ok((max_fee, tip)) => (max_fee, tip),
}

Prevention

Derive fee ceilings from live network conditions with headroom, not hardcoded values
Refresh base fee from the latest block before each signing
Treat ceiling breaches as a signal to delay, not to clamp fees below estimate
Alert when sustained base-fee levels approach the configured ceiling

When it happens

Trigger: Calling derive_fees (or prepare_and_sign_with_anchors) when base_fee_per_gas_wei plus its base_fee_buffer_bps buffer plus priority_fee_per_gas_wei exceeds max_fee_per_gas_wei — e.g. a network base-fee spike or a ceiling configured below current chain fees.

Common situations: Volatile base fee during congestion exceeding a static configured ceiling; max_fee_per_gas configured too low for current network conditions; base-fee buffer bps set too aggressively; stale fee data cached from a calmer period.

Understand the failure class

Background: "value must be between 0 and 1" / "out of range" / "must not be negative" errors: fixing range-validation failures across open-source libraries — this error's family across 42 libraries.

Related errors

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/24169ddc4e81cbd0. Report an issue: GitHub.