aws-amplify

AWS Amplify Gen 2 Best Practices

Amplify Gen 2 is a TypeScript-first, code-first full-stack platform. Embrace its opinionated nature to build robust applications efficiently.

1. Code Organization & Backend Structure

Always define your backend resources (Auth, Data, Functions) in their dedicated TypeScript files within the amplify/ directory. This ensures type safety and leverages Amplify's convention-over-configuration.

❌ BAD: Mixing resource definitions

// amplify/backend.ts
import { defineBackend } from '@aws-amplify/backend';
import { a } from '@aws-amplify/backend/data';
import { defineAuth } from '@aws-amplify/backend/auth';

const backend = defineBackend({
  auth: defineAuth({
    loginWith: { email: true },
  }),
  data: a.defineData({
    // Data schema defined directly here
    Todo: a.model({
      content: a.string(),
    }),
  }),
});

✅ GOOD: Dedicated resource files

// amplify/backend.ts
import { defineBackend } from '@aws-amplify/backend';
import { auth } from './auth/resource.js';
import { data } from './data/resource.js';

const backend = defineBackend({
  auth,
  data,
});

// amplify/auth/resource.ts
import { defineAuth } from '@aws-amplify/backend/auth';
export const auth = defineAuth({
  loginWith: { email: true },
});

// amplify/data/resource.ts
import { a } from '@aws-amplify/backend/data';
export const data = a.defineData({
  Todo: a.model({
    content: a.string(),
  }),
});

2. Backend Functions: Single Responsibility & Modularity

Adhere strictly to the Single Responsibility Principle for Amplify functions. Avoid monolithic functions or chaining Lambdas, which increase complexity and reduce maintainability. Share common logic via separate TypeScript files.

❌ BAD: Monolithic or chained functions

// amplify/functions/myFunction.ts
export const handler = async (event: any) => {
  // ... extensive logic for user creation
  // ... extensive logic for sending welcome email
  // ... extensive logic for processing data
  // ... then calls another Lambda function
};