Codelyzer is an open-source tool in Angular 8 that sits on top of TSLint. It is used to check whether Angular TypeScript projects follow a set of rules or not. It also checks the errors in codes, not following pre-defined rules. It contains more than 50 rules for checking if an Angular application follows best practices. It runs on the tslint.json file and checks only the static code in Angular 8.

Codelyzer is by default inbuilt with the projects set up with the Angular command-line interface (CLI).