This is the low-level Auth0 SDK integration for framework-agnostic SPAs like Vanilla JS, Svelte, or SolidJS. If you're using React, Angular, or Vue, skip this and use their dedicated framework SDKs instead. The skill walks you through the full setup with real code: initializing the client, handling redirect callbacks, wiring up login/logout buttons, and calling protected APIs with access tokens. It includes a build verification step that actually runs npm run build and helps you fix common integration errors like missing env var prefixes or TypeScript target mismatches. The "When NOT to Use" section alone saves you from picking the wrong Auth0 package.
npx skills add https://github.com/auth0/agent-skills --skill auth0-spa-js