vercel/next.js · error

Axes can only be defined for variable fonts.

Error message

Axes can only be defined for variable fonts.

What it means

Thrown by options_from_request() when an `axes` array is provided for a font that is NOT a variable font. Custom axes (opsz, slnt, etc.) only exist on variable fonts; the validator checks supports_variable_weight (any weight === 'variable') before allowing axes.

Source

Thrown at crates/next-core/src/next_font/google/options.rs:179

        }
    }

    let display = argument.display.unwrap_or_else(|| rcstr!("swap"));

    if !ALLOWED_DISPLAY_VALUES.contains(&display.as_str()) {
        anyhow::bail!(
            "Invalid display value {} for font {}.\nAvailable display values: {}",
            display,
            font_family,
            ALLOWED_DISPLAY_VALUES.join(", ")
        )
    }

    if let Some(axes) = argument.axes.as_ref()
        && !axes.is_empty()
    {
        if !supports_variable_weight {
            anyhow::bail!("Axes can only be defined for variable fonts.")
        }

        if weights != FontWeights::Variable {
            anyhow::bail!(
                "Axes can only be defined for variable fonts when the weight property is \
                 nonexistent or set to `variable`."
            )
        }
    }

    Ok(NextFontGoogleOptions {
        font_family,
        weights,
        styles,
        display,
        preload: argument.preload.unwrap_or(true),
        selected_variable_axes: argument.axes,
        fallback: argument.fallback,

View on GitHub (pinned to 0ae8c72462)

Solutions

1. Remove the `axes` property for non-variable fonts.
2. Switch to a variable variant of the font (one offering 'variable' weight) to use custom axes.
3. Verify the font supports the axes you want via the Google Fonts variable axes listing.

Example fix

// before
const font = Archivo_Black({ subsets: ['latin'], axes: [{ tag: 'slnt', min: -10, max: 0 }] })
// after
const font = Archivo_Black({ subsets: ['latin'] }) // not a variable font

When it happens

Trigger: Passing `axes: [...]` to a non-variable Google font (one whose available weights don't include 'variable').

Common situations: Assuming a font is variable when it isn't; copy-pasting an axes config from a variable font example onto a static font.

Related errors

• Axes can only be defined for variable fonts when the weight
• Unexpected `variable` in weight array for font {}. You only
• Only zero or one arguments to font functions are currently s
• Missing weight for {}. Available weights: {}
• Unknown weight {} for font {}. Available weights: {}

AI-assisted analysis of vercel/next.js@0ae8c72462 (2026-08-06). Data as JSON: /api/errors/6e6be992cef636af. Report an issue: GitHub.