User Auth at Scale with Next.js and AWS Amplify

Managing authentication for thousands of enterprise users is a solved problem — if you pick the right tools. Here's how we built an internal management console using Next.js App Router and AWS Amplify with Cognito.

The Problem

Our enterprise needed a self-service console for IT admins to manage user accounts, reset passwords, assign roles, and audit login activity — without going through the AWS console.

Stack

• Next.js App Router with Server Actions for mutations
• AWS Amplify for hosting and environment management
• Cognito User Pools as the identity store
• AWS SDK v3 for Cognito admin operations server-side

Key Patterns

Server Actions kept all Cognito admin calls server-side, avoiding any client exposure of admin credentials. Pagination of user lists used Cognito's token-based pagination, wrapped in a cursor abstraction for the UI.

Role assignment mapped Cognito Groups to application roles, with group membership changes propagating through a Lambda trigger.