Mini Projects

Introduction

These mini-projects are designed to help you demonstrate and deepen your knowledge of crucial frontend engineering concepts that frequently appear in technical interviews. Each project focuses on specific skills from the frontend interview topics guide and provides hands-on experience that will strengthen your technical abilities while creating portfolio-worthy demonstrations of your expertise.

Core Frontend Technologies Projects

1. Semantic HTML News Portal

Description: Build a news portal website using only HTML (no CSS or JavaScript) that showcases your mastery of semantic markup.

Learning Objectives:

• Demonstrate deep understanding of HTML5 semantic elements
• Implement proper document structure with accessibility in mind
• Create a logical information hierarchy

Project Specifications:

• Create a news homepage with sections for different categories (politics, sports, technology, etc.)
• Include a header with navigation, main content area, sidebar, and footer
• Implement article listings with proper heading hierarchy
• Add forms for user comments and search functionality
• Include appropriate metadata and schema markup for SEO

Key Features to Implement:

• ARIA attributes for enhanced accessibility
• Proper use of sectioning elements (article, section, nav, aside)
• Figure/figcaption for image handling
• Details/summary for expandable content
• Semantic tables for data presentation (e.g., sports scores)

Validation: Test your HTML with accessibility and validation tools to confirm proper semantics and structure. Use a screen reader to verify the experience works well for all users.

2. CSS Layout Master

Description: Create a responsive layout system without using any CSS frameworks, demonstrating your mastery of modern CSS layout techniques.

Learning Objectives:

• Implement advanced Flexbox and Grid layouts
• Create a responsive design that works across all device sizes
• Show understanding of CSS custom properties and reusable components

Project Specifications:

• Build a complete layout system with header, sidebar, content area, and footer
• Implement both card and list view options for content
• Create responsive navigation that transforms into a hamburger menu
• Include light/dark theme toggle using CSS variables
• Implement a responsive image gallery with proper aspect ratios

Key Features to Implement:

• Media queries for at least 4 breakpoints
• CSS Grid for overall page layout
• Flexbox for component-level layouts
• CSS custom properties for theme colors and spacing
• Responsive typography using clamp() or calc()

Validation: Test on multiple devices to verify responsive behavior. Validate that no layout breaks occur between breakpoints, and ensure smooth transitions when resizing.

3. JavaScript DOM Manipulation Library

Description: Create a lightweight DOM manipulation library similar to jQuery but using modern JavaScript.

Learning Objectives:

• Demonstrate deep understanding of DOM traversal and manipulation
• Implement event delegation and handling
• Create a chainable API through closures and prototypes

Project Specifications:

• Build a selector function that accepts CSS selectors
• Implement methods for adding/removing classes, setting attributes, and changing styles
• Create event handling functions with support for delegation
• Add DOM traversal methods (parent, children, siblings)
• Implement animation capabilities without external libraries

Key Features to Implement:

• Chainable methods for fluent API
• Event delegation for performance optimization
• Batched DOM updates for performance
• Cross-browser compatibility
• Method to extend the library with plugins

Validation: Create demo pages showing the library in action compared to vanilla DOM methods. Include performance benchmarks against other libraries.

Frontend Frameworks & Libraries Projects

4. State Management System from Scratch

Description: Build a custom state management solution similar to Redux but with a simplified API.

Learning Objectives:

• Understand core principles of state management
• Implement reducers, actions, and subscription patterns
• Create middleware for side effects

Project Specifications:

• Create a store with getState(), dispatch(), and subscribe() methods
• Implement reducer composition for different slices of state
• Add middleware support for async operations
• Include devtools for time-travel debugging
• Build selector optimization with memoization

Key Features to Implement:

• Immutable state updates
• Action creators and action types
• Middleware for logging, async operations, and routing
• State selectors with memoization
• Integration example with a UI framework

Validation: Create a demo application (todo app or similar) showing state flow and demonstrating time-travel debugging.

5. Component Library with Design System

Description: Create a small but complete UI component library with a consistent design system.

Learning Objectives:

• Implement component architecture with composition
• Create a consistent design system
• Demonstrate state management within components

Project Specifications:

• Build 8-10 core components (Button, Card, Modal, Tabs, Form elements, etc.)
• Implement a theme provider using Context API
• Create a storybook-like demo page showing component variants
• Add comprehensive prop validation
• Include accessibility features for all components

Key Features to Implement:

• Component composition patterns (compound components)
• Controlled and uncontrolled component variants
• Prop drilling alternatives
• CSS-in-JS styling (or CSS modules)
• Keyboard navigation support

Validation: Create a test application combining multiple components. Test accessibility with screen readers and keyboard-only navigation.

Performance Optimization Projects

6. Image Optimization Pipeline

Description: Build a client-side image optimization and loading system that maximizes performance.

Learning Objectives:

• Implement advanced image loading techniques
• Optimize Core Web Vitals metrics
• Create adaptive loading based on network and device capabilities

Project Specifications:

• Build a lazy-loading image component with blur-up preview
• Implement responsive images with srcset and sizes
• Create a progressive image loading system
• Add support for next-gen formats with fallbacks
• Implement aspect ratio preservation to prevent layout shifts

Key Features to Implement:

• Intersection Observer for lazy loading
• Low-quality image placeholders
• WebP/AVIF format detection and usage
• Priority hints for critical images
• Network-aware loading strategies

Validation: Test with Lighthouse and WebPageTest to verify improvements in LCP and CLS metrics compared to standard image loading.

7. Virtual Scrolling Component

Description: Create a high-performance virtual scrolling list that can handle thousands of items without performance degradation.

Learning Objectives:

• Master DOM recycling techniques for performance
• Implement scroll position virtualization
• Optimize rendering for smooth scrolling

Project Specifications:

• Build a virtualized list component that renders only visible items
• Support variable height items
• Implement smooth scrolling to arbitrary positions
• Add pull-to-refresh and infinite loading capabilities
• Include keyboard navigation support

Key Features to Implement:

• DOM recycling for memory efficiency
• Scroll position anchoring during updates
• Ahead-of-time rendering for smoothness
• Debounced rendering during fast scrolling
• requestAnimationFrame for performance optimization

Validation: Test with 10,000+ items and verify stable 60fps scrolling performance. Measure memory usage compared to a non-virtualized implementation.

Testing & Quality Assurance Projects

8. Test-Driven Component Development

Description: Develop a complex UI component (e.g., autocomplete) using strict test-driven development methodology.

Learning Objectives:

• Apply TDD principles to frontend component development
• Write comprehensive test suites for UI components
• Implement component logic driven by test requirements

Project Specifications:

• Create a complete autocomplete component with the following features:
  • Async data fetching with loading states
  • Keyboard navigation
  • Accessibility support
  • Error handling
  • Selection management
• Write tests before implementing each feature
• Include unit, integration, and end-to-end tests

Key Features to Implement:

• Jest/React Testing Library test suite
• Mock service worker for API testing
• Snapshot testing for UI stability
• User event testing for interactions
• Accessibility and keyboard navigation tests

Validation: Achieve 100% test coverage and verify all user flows work correctly. Document the TDD process showing tests written before implementation.

Web Accessibility Projects

9. Accessible Rich Internet Application

Description: Create a complex interactive widget (date picker, data table, or tree view) with comprehensive accessibility features.

Learning Objectives:

• Implement WAI-ARIA patterns correctly
• Manage focus for keyboard users
• Create screen reader-friendly interactions

Project Specifications:

• Build a fully accessible complex component
• Implement keyboard navigation with shortcuts
• Add proper ARIA attributes and roles
• Create screen reader announcements for dynamic content
• Support high contrast mode and reduced motion preferences

Key Features to Implement:

• Focus management system
• ARIA live regions for announcements
• Custom keyboard shortcuts with documentation
• State management tied to ARIA attributes
• Support for Windows High Contrast Mode

Validation: Test with screen readers (NVDA, VoiceOver, JAWS) and verify keyboard-only navigation. Run automated accessibility tests and perform manual testing with the WAI checklist.

API Integration Projects

10. Offline-First Application

Description: Build a small application that works seamlessly offline with data synchronization.

Learning Objectives:

• Implement service workers for offline support
• Create robust data synchronization patterns
• Handle conflict resolution in offline data

Project Specifications:

• Create a progressive web app with complete offline functionality
• Implement a sync queue for offline actions
• Add optimistic UI updates with rollback capability
• Create conflict resolution strategy for synchronized data
• Add offline indicators and seamless online/offline transitions

Key Features to Implement:

• Service Worker cache strategies
• IndexedDB for offline data storage
• Background sync API
• Conflict detection and resolution
• Network status monitoring with recovery

Validation: Test application by toggling network connection off/on and verifying data integrity and synchronization behaviors.

Browser Concepts Projects

11. Custom Browser Storage System

Description: Create a unified storage system that intelligently uses different browser storage mechanisms.

Learning Objectives:

• Master different browser storage APIs
• Implement storage limitations handling
• Create data persistence strategies

Project Specifications:

• Build a storage API that automatically selects the appropriate storage mechanism
• Implement quota management and fallback strategies
• Add encryption for sensitive data
• Create garbage collection for unused data
• Include migration system for schema changes

Key Features to Implement:

• Unified API over multiple storage types (localStorage, IndexedDB, Cache API)
• Storage prioritization based on data type and size
• Automatic pruning of old data
• Encryption/decryption of sensitive information
• Storage analytics and quota monitoring

Validation: Create a test application that demonstrates data persistence across page refreshes, browser restarts, and even when clearing specific storage types.

Frontend Architecture Projects

12. Micro-Frontend Architecture Demo

Description: Create a small-scale demonstration of micro-frontend architecture with multiple independently deployable applications.

Learning Objectives:

• Implement module federation for sharing code
• Create boundaries between application sections
• Manage shared state across micro-frontends

Project Specifications:

• Build a container application that hosts multiple micro-frontends
• Implement at least 3 distinct micro-frontend applications
• Create shared component library accessible to all micro-frontends
• Implement cross-micro-frontend navigation and communication
• Add versioning strategy for independent deployments

Key Features to Implement:

• Webpack Module Federation
• Runtime integration of micro-frontends
• Shared authentication and user context
• Event-based communication between micro-frontends
• Independent styling with CSS isolation

Validation: Verify that each micro-frontend can be developed and deployed independently while functioning correctly within the container application.

Build Tools & Development Environment Projects

13. Custom Webpack Plugin

Description: Create a custom Webpack plugin that improves the development or build process.

Learning Objectives:

• Understand webpack internals and plugin system
• Implement build optimizations
• Create developer experience improvements

Project Specifications:

• Build a webpack plugin that solves a specific problem, such as:
  • Automated image optimization
  • Bundle analysis and bloat detection
  • Custom code splitting strategies
  • Development-time performance monitoring
  • CSS optimization

Key Features to Implement:

• Webpack plugin lifecycle hooks
• Asset processing pipeline
• Build statistics generation
• Integration with other tools
• Configuration options for customization

Validation: Compare builds with and without your plugin to demonstrate measurable improvements in bundle size, build time, or developer experience.

Frontend Problem-Solving Projects

14. Drag-and-Drop Interface Builder

Description: Create a drag-and-drop interface that allows users to build layouts visually.

Learning Objectives:

• Implement complex drag-and-drop interactions
• Create a serializable component system
• Manage complex state transformations

Project Specifications:

• Build a canvas where users can drag and drop components
• Implement resize and positioning capabilities
• Create property editors for components
• Add undo/redo functionality
• Implement save/load of layouts as JSON

Key Features to Implement:

• Custom drag-and-drop system (or integrate library)
• Position calculation with snapping
• Tree representation of component hierarchy
• History management for state
• JSON serialization/deserialization

Validation: Create several complex layouts using your builder and verify the exported JSON can be correctly re-imported.

Advanced Technical Projects

15. Real-Time Collaborative Editor

Description: Build a simplified collaborative text editor with real-time synchronization.

Learning Objectives:

• Implement operational transformation or CRDT algorithms
• Create real-time client-server communication
• Manage complex state synchronization

Project Specifications:

• Create a text editor with real-time collaboration features
• Implement cursor presence to show other users’ positions
• Add conflict resolution for simultaneous edits
• Create history/versioning system
• Add offline editing with synchronization

Key Features to Implement:

• WebSockets for real-time communication
• Operational Transformation or CRDT algorithm
• Cursor tracking and rendering
• Version control system
• Conflict resolution strategy

Validation: Test with multiple simultaneous users editing the same document and verify content remains synchronized without conflicts.

Conclusion

These mini-projects cover the key technical areas assessed in frontend engineering interviews while providing tangible demonstrations of your skills. By completing these projects, you’ll not only master the concepts but also build a compelling portfolio that showcases your abilities.

Each project is designed to deepen your understanding through practical application, aligning with research showing that “scenario-based learning improves retention through participation in realistic situations” and provides “better interactivity, bridging the gap between theory and practice.”

The projects range from foundational skills to advanced concepts, making them suitable for engineers at all levels. Senior and staff engineer candidates should focus particularly on the architecture, performance, and advanced projects to demonstrate the higher-level thinking required for those roles.