TypeScript

To get proper TypeScript support when accessing the Better Auth instance from Strapi, you need to extend Strapi's internal types.

Extending Strapi types

Create a new file in the types directory of your Strapi app:

types/better-auth.d.ts

import type {} from "@strapi/types/dist/core/strapi";

declare module "@strapi/types/dist/core/strapi" {
  interface StrapiInternalConfig {
    "better-auth": ReturnType<
      typeof import("../config/better-auth").default
    >;
  }

  interface Strapi {
    internal_config: StrapiInternalConfig;
  }
}

Once this file is in place, TypeScript will correctly type the Better Auth instance when you access it:

// Fully typed — no casting required
const auth = strapi.internal_config["better-auth"];