[Vue warn]: Invalid prop: type check failed Vue Origin: On your device OSI layer 7 · Application Last updated 5 Nov 2026

Vue: [Vue warn]: Invalid prop: type check failed for prop "count". Expected Number with value 5, got String with value "5"

A prop received a value of the wrong type.

Exact message you may see [Vue warn]: Invalid prop: type check failed for prop "count". Expected Number with value 5, got String with value "5"Invalid prop: type check failed for prop[Vue warn]: Invalid prop: type check failed for prop "user". Expected Object, got NullInvalid prop: custom validator check failed for prop
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Seen on: Vue

Meaning

Pass the right type: use :count="5" (bound) instead of count="5" (string). Update the prop definition or convert values. For several types use [String, Number]. Validators and required are separate warnings.

Common causes

  • Static attribute passes a string (count="5")
  • API data type differs
  • Prop declared with wrong type
  • null/undefined for a typed prop
  • Boolean casting with empty attr

⚡ Quick fix

  1. <Cmp :count="5" /> (v-bind)
  2. Allow multiple types: type: [Number, String]
  3. Convert data before passing

Detailed fix by platform

Vue

  1. defineProps<{ count: number }>()

How to diagnose

  1. Binding — : or static?
  2. Type — Declared?
  3. Data — Converted?

🔧 Still not fixed?

Many errors look alike. If the steps above didn’t solve it, one of these is probably what you’re facing:

Where this error sits

Origin: On your device. Errors that are often confused with or caused by this one (click to open):

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