# kalviumcommunity/backend-web-development architecture

> Architecture diagram of the GitHub repository kalviumcommunity/backend-web-development, generated by GitDiagram from its file tree, README and a sample of source files (last updated 2026-09-28). It is an AI-made overview: check details against the source.

- Interactive diagram: https://gitdiagram.com/kalviumcommunity/backend-web-development
- Repository: https://github.com/kalviumcommunity/backend-web-development

## Overview

This is a course repository of starter assignments, not one deployable backend. Its examples cover Express foundations, layered APIs and persistence, identity/security, and backend integrations. The sampled code supports the shown mounts and controller-to-service calls; other capabilities are represented from the file tree, with uncertain wiring omitted.

Main entry points: [`Module 2/Express Middleware Architecture/app.js`](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%202/Express%20Middleware%20Architecture/app.js) (Middleware app), [`Module 3/Backend Data Flow/controllers/postsController.js`](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%203/Backend%20Data%20Flow/controllers/postsController.js) (Posts controller), [`Module 3/Backend Data Flow/app.js`](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%203/Backend%20Data%20Flow/app.js) (Posts API app), [`Module 2/Supporting Layers/app.js`](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%202/Supporting%20Layers/app.js) (Articles app)

## Diagram (Mermaid)

```mermaid
flowchart TD

subgraph group_express["Express Foundations"]
  node_mwapp["Middleware app<br/>[app.js]"]
  node_postrouter["Posts router<br/>[posts.js]"]
  node_userrouter["Users router<br/>[users.js]"]
  node_requestid["Request ID<br/>[requestId.js]"]
  node_logger["Request logger<br/>[logger.js]"]
  node_timing["Request timing<br/>[timing.js]"]
  node_articlesapp["Articles app<br/>[app.js]"]
  node_articlesroute["Articles routes<br/>[articles.js]"]
  node_articlescontroller["Articles controller"]
  node_articleservice["Articles service<br/>[articlesService.js]"]
end

subgraph group_api["APIs and Data"]
  node_postsapp["Posts API app<br/>[app.js]"]
  node_postsroute["Posts routes<br/>[posts.js]"]
  node_postscontroller["Posts controller<br/>[postsController.js]"]
  node_postsservice["Posts service<br/>[postsService.js]"]
  node_commentsservice["Comments service<br/>[commentsService.js]"]
  node_votesservice["Votes service<br/>[votesService.js]"]
  node_postrepo[("Posts repository<br/>[postsRepo.js]")]
  node_commentsrepo[("Comments repository<br/>[commentsRepo.js]")]
  node_votesrepo[("Votes repository<br/>[votesRepo.js]")]
  node_validation["Post validator<br/>[post.validator.js]"]
end

subgraph group_identity["Identity and Security"]
  node_authmiddleware["Request identity<br/>[auth.js]"]
  node_authfundamentals["Auth routes<br/>[authRoutes.js]"]
  node_jwtmiddleware["JWT verification<br/>[requireAuth.js]"]
  node_rolemiddleware["Role authorization<br/>[requireRole.js]"]
  node_sessionroutes["Session routes<br/>[authRoutes.js]"]
  node_sessionstore[("Session store<br/>[sessionStore.js]")]
end

subgraph group_integrations["Backend Integrations"]
  node_queue["Job queue<br/>[queue.js]"]
  node_worker["Job worker<br/>[worker.js]"]
  node_email["Email sender<br/>[email.js]"]
  node_redis[("Redis cache<br/>[cache.js]")]
  node_webhook["Webhook handler<br/>[webhookHandler.js]"]
  node_eventhandlers["Event handlers<br/>[eventHandlers.js]"]
  node_socket["Socket server<br/>[socket.js]"]
end

node_learner(("API client"))

node_learner -->|"sends requests"| node_mwapp
node_mwapp -->|"mounts middleware"| node_requestid
node_mwapp -->|"mounts middleware"| node_logger
node_mwapp -->|"mounts middleware"| node_timing
node_mwapp -->|"mounts at /posts"| node_postrouter
node_mwapp -->|"mounts at /users"| node_userrouter
node_articlesapp -->|"mounts at /articles"| node_articlesroute
node_articlesapp -->|"serves API"| node_learner
node_articlescontroller -->|"calls methods"| node_articleservice
node_postsapp -->|"applies identity"| node_authmiddleware
node_postsapp -->|"mounts at /posts"| node_postsroute
node_learner -->|"sends requests"| node_postsapp
node_postscontroller -->|"calls methods"| node_postsservice
node_postscontroller -->|"adds comments"| node_commentsservice
node_postscontroller -->|"casts votes"| node_votesservice

click node_mwapp "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%202/Express%20Middleware%20Architecture/app.js"
click node_postrouter "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%202/Express%20Middleware%20Architecture/routes/posts.js"
click node_userrouter "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%202/Express%20Middleware%20Architecture/routes/users.js"
click node_requestid "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%202/Express%20Middleware%20Architecture/middleware/requestId.js"
click node_logger "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%202/Express%20Middleware%20Architecture/middleware/logger.js"
click node_timing "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%202/Express%20Middleware%20Architecture/middleware/timing.js"
click node_articlesapp "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%202/Supporting%20Layers/app.js"
click node_articlesroute "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%202/Supporting%20Layers/routes/articles.js"
click node_articlescontroller "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%202/Supporting%20Layers/controllers/articlesController.js"
click node_articleservice "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%202/Supporting%20Layers/services/articlesService.js"
click node_postsapp "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%203/Backend%20Data%20Flow/app.js"
click node_postsroute "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%203/Backend%20Data%20Flow/routes/posts.js"
click node_postscontroller "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%203/Backend%20Data%20Flow/controllers/postsController.js"
click node_postsservice "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%203/Backend%20Data%20Flow/services/postsService.js"
click node_commentsservice "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%203/Backend%20Data%20Flow/services/commentsService.js"
click node_votesservice "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%203/Backend%20Data%20Flow/services/votesService.js"
click node_postrepo "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%203/Backend%20Data%20Flow/repository/postsRepo.js"
click node_commentsrepo "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%203/Backend%20Data%20Flow/repository/commentsRepo.js"
click node_votesrepo "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%203/Backend%20Data%20Flow/repository/votesRepo.js"
click node_validation "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%203/Backend%20Data%20Flow/validators/post.validator.js"
click node_authmiddleware "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%203/Backend%20Data%20Flow/middleware/auth.js"
click node_authfundamentals "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%204/Authentication%20Fundamentals/src/routes/authRoutes.js"
click node_jwtmiddleware "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%204/JWT%20Verification%20Depth/src/middleware/requireAuth.js"
click node_rolemiddleware "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%204/Authorization%20and%20RBAC/src/middleware/requireRole.js"
click node_sessionroutes "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%204/Cookies%2C%20Sessions%20and%20Authentication/src/routes/authRoutes.js"
click node_sessionstore "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%204/Cookies%2C%20Sessions%20and%20Authentication/src/session/sessionStore.js"
click node_queue "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%204/Background%20Jobs%20BullMQ/src/queue.js"
click node_worker "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%204/Background%20Jobs%20BullMQ/src/worker.js"
click node_email "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%204/Background%20Jobs%20BullMQ/src/email.js"
click node_redis "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%204/Caching%20with%20Redis/src/cache.js"
click node_webhook "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%204/Introduction%20to%20Webhooks/src/webhookHandler.js"
click node_eventhandlers "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%204/Introduction%20to%20Webhooks/src/eventHandlers.js"
click node_socket "https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%204/WebSockets%20and%20Socket.IO/src/socket.js"

classDef toneNeutral fill:#f8fafc,stroke:#334155,stroke-width:1.5px,color:#0f172a
classDef toneBlue fill:#dbeafe,stroke:#2563eb,stroke-width:1.5px,color:#172554
classDef toneAmber fill:#fef3c7,stroke:#d97706,stroke-width:1.5px,color:#78350f
classDef toneMint fill:#dcfce7,stroke:#16a34a,stroke-width:1.5px,color:#14532d
classDef toneRose fill:#ffe4e6,stroke:#e11d48,stroke-width:1.5px,color:#881337
classDef toneIndigo fill:#e0e7ff,stroke:#4f46e5,stroke-width:1.5px,color:#312e81
classDef toneTeal fill:#ccfbf1,stroke:#0f766e,stroke-width:1.5px,color:#134e4a
class node_mwapp,node_postrouter,node_userrouter,node_requestid,node_logger,node_timing,node_articlesapp,node_articlesroute,node_articlescontroller,node_articleservice,node_learner toneBlue
class node_postsapp,node_postsroute,node_postscontroller,node_postsservice,node_commentsservice,node_votesservice,node_postrepo,node_commentsrepo,node_votesrepo,node_validation toneAmber
class node_authmiddleware,node_authfundamentals,node_jwtmiddleware,node_rolemiddleware,node_sessionroutes,node_sessionstore toneMint
class node_queue,node_worker,node_email,node_redis,node_webhook,node_eventhandlers,node_socket toneRose
```

## Components

### Express Foundations

- [Middleware app](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%202/Express%20Middleware%20Architecture/app.js): `Module 2/Express Middleware Architecture/app.js`
- [Posts router](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%202/Express%20Middleware%20Architecture/routes/posts.js): `Module 2/Express Middleware Architecture/routes/posts.js`
- [Users router](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%202/Express%20Middleware%20Architecture/routes/users.js): `Module 2/Express Middleware Architecture/routes/users.js`
- [Request ID](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%202/Express%20Middleware%20Architecture/middleware/requestId.js): `Module 2/Express Middleware Architecture/middleware/requestId.js`
- [Request logger](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%202/Express%20Middleware%20Architecture/middleware/logger.js): `Module 2/Express Middleware Architecture/middleware/logger.js`
- [Request timing](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%202/Express%20Middleware%20Architecture/middleware/timing.js): `Module 2/Express Middleware Architecture/middleware/timing.js`
- [Articles app](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%202/Supporting%20Layers/app.js): `Module 2/Supporting Layers/app.js`
- [Articles routes](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%202/Supporting%20Layers/routes/articles.js): `Module 2/Supporting Layers/routes/articles.js`
- [Articles controller](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%202/Supporting%20Layers/controllers/articlesController.js): `Module 2/Supporting Layers/controllers/articlesController.js`
- [Articles service](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%202/Supporting%20Layers/services/articlesService.js): `Module 2/Supporting Layers/services/articlesService.js`

### APIs and Data

- [Posts API app](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%203/Backend%20Data%20Flow/app.js): `Module 3/Backend Data Flow/app.js`
- [Posts routes](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%203/Backend%20Data%20Flow/routes/posts.js): `Module 3/Backend Data Flow/routes/posts.js`
- [Posts controller](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%203/Backend%20Data%20Flow/controllers/postsController.js): `Module 3/Backend Data Flow/controllers/postsController.js`
- [Posts service](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%203/Backend%20Data%20Flow/services/postsService.js): `Module 3/Backend Data Flow/services/postsService.js`
- [Comments service](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%203/Backend%20Data%20Flow/services/commentsService.js): `Module 3/Backend Data Flow/services/commentsService.js`
- [Votes service](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%203/Backend%20Data%20Flow/services/votesService.js): `Module 3/Backend Data Flow/services/votesService.js`
- [Posts repository](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%203/Backend%20Data%20Flow/repository/postsRepo.js): `Module 3/Backend Data Flow/repository/postsRepo.js`
- [Comments repository](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%203/Backend%20Data%20Flow/repository/commentsRepo.js): `Module 3/Backend Data Flow/repository/commentsRepo.js`
- [Votes repository](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%203/Backend%20Data%20Flow/repository/votesRepo.js): `Module 3/Backend Data Flow/repository/votesRepo.js`
- [Post validator](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%203/Backend%20Data%20Flow/validators/post.validator.js): `Module 3/Backend Data Flow/validators/post.validator.js`

### Identity and Security

- [Request identity](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%203/Backend%20Data%20Flow/middleware/auth.js): `Module 3/Backend Data Flow/middleware/auth.js`
- [Auth routes](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%204/Authentication%20Fundamentals/src/routes/authRoutes.js): `Module 4/Authentication Fundamentals/src/routes/authRoutes.js`
- [JWT verification](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%204/JWT%20Verification%20Depth/src/middleware/requireAuth.js): `Module 4/JWT Verification Depth/src/middleware/requireAuth.js`
- [Role authorization](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%204/Authorization%20and%20RBAC/src/middleware/requireRole.js): `Module 4/Authorization and RBAC/src/middleware/requireRole.js`
- [Session routes](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%204/Cookies%2C%20Sessions%20and%20Authentication/src/routes/authRoutes.js): `Module 4/Cookies, Sessions and Authentication/src/routes/authRoutes.js`
- [Session store](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%204/Cookies%2C%20Sessions%20and%20Authentication/src/session/sessionStore.js): `Module 4/Cookies, Sessions and Authentication/src/session/sessionStore.js`

### Backend Integrations

- [Job queue](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%204/Background%20Jobs%20BullMQ/src/queue.js): `Module 4/Background Jobs BullMQ/src/queue.js`
- [Job worker](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%204/Background%20Jobs%20BullMQ/src/worker.js): `Module 4/Background Jobs BullMQ/src/worker.js`
- [Email sender](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%204/Background%20Jobs%20BullMQ/src/email.js): `Module 4/Background Jobs BullMQ/src/email.js`
- [Redis cache](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%204/Caching%20with%20Redis/src/cache.js): `Module 4/Caching with Redis/src/cache.js`
- [Webhook handler](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%204/Introduction%20to%20Webhooks/src/webhookHandler.js): `Module 4/Introduction to Webhooks/src/webhookHandler.js`
- [Event handlers](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%204/Introduction%20to%20Webhooks/src/eventHandlers.js): `Module 4/Introduction to Webhooks/src/eventHandlers.js`
- [Socket server](https://github.com/kalviumcommunity/backend-web-development/blob/main/Module%204/WebSockets%20and%20Socket.IO/src/socket.js): `Module 4/WebSockets and Socket.IO/src/socket.js`

### Other components

- **API client**

## Connections

- API client → Middleware app: sends requests
- Middleware app → Request ID: mounts middleware
- Middleware app → Request logger: mounts middleware
- Middleware app → Request timing: mounts middleware
- Middleware app → Posts router: mounts at /posts
- Middleware app → Users router: mounts at /users
- Articles app → Articles routes: mounts at /articles
- Articles app → API client: serves API
- Articles controller → Articles service: calls methods
- Posts API app → Request identity: applies identity
- Posts API app → Posts routes: mounts at /posts
- API client → Posts API app: sends requests
- Posts controller → Posts service: calls methods
- Posts controller → Comments service: adds comments
- Posts controller → Votes service: casts votes