Amplify

Front-end teams shipping a React / Vue / Next.js / mobile app need hosting with a build pipeline and a CDN, plus a backend for auth, an API, a database, and file uploads — and they don’t want to hand-assemble Cognito + AppSync + DynamoDB + S3 + CloudFront + a CI job. AWS Amplify packages that: Amplify Hosting connects to your git repo and does build → deploy → global CDN with per-branch environments and pull-request previews; Amplify’s backend tooling provisions Cognito (auth), AppSync/API Gateway (data & APIs), and S3 (storage) from a config, with client libraries that wire the front end to them.

• Hosting serves your app from a global CloudFront distribution (edge locations worldwide); the build pipeline and the backend resources run in a Region you pick.
• Backend resources (Cognito user pools, AppSync APIs, DynamoDB tables, S3 buckets) are Regional and carry their own multi-AZ durability — Amplify just provisions and connects them.
• Each git branch can map to its own environment (dev / staging / prod), each with an isolated backend stack.

graph LR
REPO["Git repo (push / open PR)"] --> HOST
subgraph HOST["Amplify Hosting"]
  BUILD["Build + deploy"]
  CDN["Global CDN (CloudFront)"]
  PREV["PR preview environments"]
  BUILD --> CDN
end
CDN --> USERS(("Users"))
HOST -.-> BE
subgraph BE["Amplify backend (Regional)"]
  AUTH["Auth - Cognito"]
  DATA["Data / API - AppSync + DynamoDB"]
  STORE["Storage - S3"]
end
classDef host fill:#f3ecfb,stroke:#8b3de0,stroke-width:2px,color:#3a1a5c
classDef be fill:#e8f0fe,stroke:#3b82f6,stroke-width:2px,color:#173a70
class BUILD,CDN host
class AUTH,DATA,STORE be

Hosting bills for build minutes, data stored, and data served from the CDN. The backend is just the underlying services at their normal rates — Cognito MAUs, AppSync requests, DynamoDB, S3. There’s no Amplify “platform fee” beyond hosting; a small app with modest traffic lands in or near the free tier, and cost scales with build frequency and CDN egress.

• Trigger phrases: “host a web / mobile front end with CI/CD and a CDN,” “quickly add auth, a GraphQL/REST API, and file storage to an app,” “pull-request preview environments,” “full-stack app with minimal backend work” → Amplify.
• Amplify Hosting vs S3 + CloudFront: Amplify adds the git-triggered build pipeline, branch environments, PR previews, redirects/rewrites, and SSR support on top; plain S3+CloudFront is just static hosting you deploy to yourself.
• Amplify vs App Runner / Elastic Beanstalk: Amplify targets front-end apps + a managed serverless backend; App Runner/Beanstalk target server-side application containers/code.
• Backend is Cognito + AppSync + DynamoDB + S3 under the hood — if a question describes those being set up together for a mobile app, Amplify is the packaging.
• Custom domains get an AWS-managed TLS certificate automatically.