multica-ai/multica · error

value must be a number

Error message

value must be a number

What it means

validatePropertyValue requires number-type property values to arrive as a JSON number, which Go's encoding/json decodes into float64. Sending the number as a string, boolean, object, or array fails this type assertion. Note the code does no range or integer check — only the JSON type matters.

Source

Thrown at server/internal/handler/property.go:345

		}
		return json.Marshal(sanitizeNullBytes(s))
	case "url":
		s, ok := v.(string)
		if !ok {
			return nil, errors.New("value must be a URL string")
		}
		s = strings.TrimSpace(s)
		if len(s) > maxPropertyURLValueLen {
			return nil, fmt.Errorf("value must be %d characters or fewer", maxPropertyURLValueLen)
		}
		u, err := url.Parse(s)
		if err != nil || (u.Scheme != "http" && u.Scheme != "https") || u.Host == "" {
			return nil, errors.New("value must be an http(s) URL")
		}
		return json.Marshal(s)
	case "number":
		if _, ok := v.(float64); !ok {
			return nil, errors.New("value must be a number")
		}
		return json.Marshal(v)
	case "checkbox":
		if _, ok := v.(bool); !ok {
			return nil, errors.New("value must be true or false")
		}
		return json.Marshal(v)
	case "date":
		s, ok := v.(string)
		if !ok {
			return nil, errors.New("value must be a date string in YYYY-MM-DD format")
		}
		if _, err := time.Parse("2006-01-02", s); err != nil {
			return nil, errors.New("value must be a date string in YYYY-MM-DD format")
		}
		return json.Marshal(s)
	case "select":
		s, ok := v.(string)

View on GitHub (pinned to 2c0912b6ec)

Solutions

1. Send a raw JSON number: {"value": 42} not {"value": "42"}
2. Parse form input with Number(...) before building the payload
3. For values exceeding float64 precision, be aware the backend stores float64 — round or clamp client-side

Example fix

// before
{ value: "42" }
// after
{ value: 42 }

if (def.type === 'number') {
  const n = Number(value);
  if (Number.isNaN(n)) throw new Error('Property expects a JSON number');
  payload.value = n;
}

function isNumberPropertyValue(v: unknown): v is number {
  return typeof v === 'number' && Number.isFinite(v);
}

When it happens

Trigger: PUT/PATCH a number property with {"value": "42"} (quoted), {"value": true}, or {"value": {"n": 42}}. Typical when HTML form inputs produce strings and the client forgets to parse them, or a strict-typed client sends BigInt as a string.

Common situations: Form submissions where quantity/estimate fields arrive as text; spreadsheet imports mapping cells to strings; JSON.stringify of values already stringified once.

Related errors

• value cannot be empty (use DELETE to unset a property)
• value must be a URL string
• value must be an http(s) URL
• value must be true or false
• value must be a date string in YYYY-MM-DD format

AI-assisted analysis of multica-ai/multica@2c0912b6ec (2026-08-15). Data as JSON: /api/errors/7bc257a1ab853b8b. Report an issue: GitHub.