d2lang/d2 · error

"%v" is not a valid font in our system

Error message

"%v" is not a valid font in our system

What it means

The "font" style key must name a font family present in d2fonts.D2_FONT_TO_FAMILY. The value is checked case-insensitively; unknown names produce this error naming the offending value.

Source

Thrown at d2graph/d2graph.go:409

		if err != nil {
			return errors.New(`expected "3d" to be true or false`)
		}
		s.ThreeDee.Value = value
	case "multiple":
		if s.Multiple == nil {
			break
		}
		_, err := strconv.ParseBool(value)
		if err != nil {
			return errors.New(`expected "multiple" to be true or false`)
		}
		s.Multiple.Value = value
	case "font":
		if s.Font == nil {
			break
		}
		if _, ok := d2fonts.D2_FONT_TO_FAMILY[strings.ToLower(value)]; !ok {
			return fmt.Errorf(`"%v" is not a valid font in our system`, value)
		}
		s.Font.Value = strings.ToLower(value)
	case "font-size":
		if s.FontSize == nil {
			break
		}
		f, err := strconv.Atoi(value)
		if err != nil || (f < 8 || f > 100) {
			return errors.New(`expected "font-size" to be a number between 8 and 100`)
		}
		s.FontSize.Value = value
	case "font-color":
		if s.FontColor == nil {
			break
		}
		if !color.ValidColor(value) {
			return errors.New(`expected "font-color" to be a valid named color ("orange"), a hex code ("#f0ff3a"), or a gradient ("linear-gradient(red, blue)")`)
		}

View on GitHub (pinned to 0d69dca6f5)

Solutions

1. Use a built-in family name listed in d2fonts.D2_FONT_TO_FAMILY (lowercase matching)
2. Register a custom font by providing the TTF files via the font flags so the family becomes valid
3. Fix spelling/spacing of the font name

Example fix

// before
x.style.font: Arial
// after
x.style.font: Source Sans Pro

if _, ok := d2fonts.D2_FONT_TO_FAMILY[strings.ToLower(fontName)]; !ok {
	// invalid font family — register via --font-* flags or pick a built-in
}

func validFontFamily(v string) bool {
	_, ok := d2fonts.D2_FONT_TO_FAMILY[strings.ToLower(v)]
	return ok
}

if err := obj.SetStyle("font", v); err != nil {
	return fmt.Errorf("font %q unavailable: %v", v, err)
}

When it happens

Trigger: Setting `style.font` on a shape/element to a value not in D2_FONT_TO_FAMILY — e.g. `font: Arial` or `font: Comic Sans` instead of built-in families like Source Sans Pro, Source Code Pro, or custom fonts loaded via loadFonts.

Common situations: Assuming any system-installed font works, forgetting to register a custom font family via the --font-* flags, or using a font name with wrong spacing/casing combined with missing registration.

Related errors

• expected "shadow" to be true or false
• expected "3d" to be true or false
• expected "multiple" to be true or false
• expected "font-size" to be a number between 8 and 100
• expected "font-color" to be a valid named color ("orange"),

AI-assisted analysis of d2lang/d2@0d69dca6f5 (2026-08-31). Data as JSON: /api/errors/609bdc1b5913daf9. Report an issue: GitHub.