nautechsystems/nautilus_trader · error

invalid price `{value}` at precision {precision}: {e}

Error message

invalid price `{value}` at precision {precision}: {e}

What it means

After the string parses as a Decimal, parse_price calls Price::from_decimal_dp to build a Nautilus Price at the requested precision. This error means the decimal value is out of Price's representable range at that precision (or the precision conversion itself failed) — e.g. a price far beyond the fixed-precision mantissa capacity, or more fractional digits than the requested precision can hold without loss. The value and precision are included in the message.

Source

Thrown at crates/adapters/lighter/src/common/parse.rs:99

        anyhow::anyhow!("Quantity overflow for ticks={ticks}, decimals={decimals}: {e}")
    })
}

/// Converts a decimal string into a Nautilus [`Price`] at the requested precision.
///
/// # Errors
///
/// Returns an error if the string is not a decimal, if `precision` exceeds
/// [`MAX_DECIMALS`], or if the resulting value is out of range.
pub fn parse_price(value: &str, precision: u8) -> anyhow::Result<Price> {
    anyhow::ensure!(
        precision <= MAX_DECIMALS,
        "price precision {precision} exceeds maximum {MAX_DECIMALS}",
    );
    let decimal =
        Decimal::from_str(value).map_err(|e| anyhow::anyhow!("invalid price `{value}`: {e}"))?;
    Price::from_decimal_dp(decimal, precision)
        .map_err(|e| anyhow::anyhow!("invalid price `{value}` at precision {precision}: {e}"))
}

/// Converts a decimal string into a non-negative Nautilus [`Quantity`].
///
/// Zero is allowed because Lighter sends zero-size book levels to delete
/// existing orders.
///
/// # Errors
///
/// Returns an error if the string is not a decimal, if `precision` exceeds
/// [`MAX_DECIMALS`], if the value is negative, or if the resulting quantity
/// is out of range.
pub fn parse_quantity(value: &str, precision: u8) -> anyhow::Result<Quantity> {
    anyhow::ensure!(
        precision <= MAX_DECIMALS,
        "size precision {precision} exceeds maximum {MAX_DECIMALS}",
    );
    let decimal =

View on GitHub (pinned to 18893faf8b)

Solutions

  1. Check that the precision argument matches the market's actual price_decimals from orderBookDetails.
  2. Validate the price against the instrument's price band / plausible range before parsing and reject absurd values upstream.
  3. Verify the raw payload — a value this large usually indicates a corrupted or fabricated message; drop the update and log the raw string.
  4. If legitimate values are being rejected, confirm you are not accidentally passing an exponent-scaled mantissa instead of the human-readable price.

Example fix

// before
let price = parse_price(value_str, precision)?;
// after
let price = parse_price(value_str, market.price_decimals)?;
anyhow::ensure!(price > Price::zero(), "price {} out of band", price);
Defensive patterns

Strategy: validation

Validate before calling

fn price_plausible(value: &str, max_price: f64) -> bool {
    value.parse::<f64>().map(|v| v.is_finite() && v > 0.0 && v <= max_price).unwrap_or(false)
}

Try / catch

match parse_price(raw, precision) {
    Ok(p) => p,
    Err(e) if e.to_string().contains("at precision") => {
        tracing::error!(raw = %raw, "price out of Price range; dropping update");
        return Ok(());
    }
    Err(e) => return Err(e.into()),
}

Prevention

When it happens

Trigger: Calling parse_price with a valid decimal string whose magnitude overflows Price's fixed-point range (astronomically large value), or a value with more decimal places than the requested precision in contexts where from_decimal_dp rejects the conversion.

Common situations: A corrupt or malicious feed payload with a 30-digit price; misconfigured precision (e.g. precision=2 for a value like "0.000001"); test cases probing Price bounds with f64::MAX-style literals.

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/15b964ae5034c13c. Report an issue: GitHub.