NG0300 Angular Origin: On your device Last updated 15 Oct 2026

Angular: NG0300: Multiple components match node with tagname app-x: A and B

Two components in scope share the same selector, so Angular cannot decide which one renders for that tag.

Exact message you may see NG0300: Multiple components match node with tagnameMultiple components match node with tagnametwo components match the same selector
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Seen on: Angular TypeScript

Meaning

A given element can be matched by only one component. It happens when two components (or modules) declare the same selector, when a duplicate component is imported twice through different NgModules, or when a library component clashes with yours.

Common causes

  • Two components with identical selector values in scope
  • The same component declared in two NgModules
  • Own component selector clashes with a library one (app-button vs a UI kit)
  • Copy-pasted component not renamed
  • Standalone import list containing two components with one selector

⚡ Quick fix

  1. Give each component a unique selector prefix
  2. Remove one of the duplicate imports/declarations
  3. Search the project for the selector named in the message

Detailed fix by platform

Angular CLI

  1. Search quickly: grep -rn "selector: 'app-x'" src/
  2. Set a project prefix in angular.json ("prefix": "acme") and regenerate

How to diagnose

  1. Selector — Which two components are named?
  2. Scope — Where are both imported or declared?
  3. Origin — Library or own code?

🔧 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):

Cannot find control with name — Angular: Error: Cannot find control with name: 'email' (reactive forms) (Angular)Cannot find control w…Could not find the builder's node package — Angular CLI: Could not find the '@angular-devkit/build-angular:browser' builder's node package / Cannot find module '@angular-devkit/build-angular/package.json' (Angular)Could not find the bu…exceeded maximum budget — Angular build: Error: bundle initial exceeded maximum budget. Budget 1.00 MB was not met by 120.00 kB with a total of 1.12 MB (Angular)exceeded maximum budg…NG0912 — Angular: NG0912: Component ID generation collision detected. Components 'A' and 'B' with selector 'app-x' use the same ID (Angular)NG0912NG6008 — Angular: NG6008: Component X is standalone, and cannot be declared in an NgModule. Did you mean to import it instead? (Angular)NG6008NG8001 — Angular: NG8001: 'app-item' is not a known element — verify that it is included in the component's imports (Angular)NG8001Schema validation failed with the following errors — Angular CLI: Schema validation failed with the following errors: Data path "" must NOT have additional properties(xyz) (Angular)Schema validation fai…NG0300

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