Practical developer solutions, in-depth troubleshooting guides, and free online developer tools.
DevFixHub is a production-quality, fast, lightweight, and SEO-optimized developer portal built with Next.js 15, React 19, TypeScript, and Tailwind CSS. It is designed from the ground up for high search visibility, zero-latency browser tools, and Google AdSense monetization.
π Live Website: https://devfixhub.site
π¦ GitHub Repository: https://github.com/lasithadilshan/DevFixHub
βοΈ Hosting: Cloudflare Pages (Global Edge CDN, Automatic SSL & Static HTML Export)
β‘ Vercel Mirror: https://devfixhub.vercel.app (Configured with 308 permanent redirects to devfixhub.site)
- Project Overview
- Key Features
- Technology Stack
- Project Structure
- Installation & Setup
- Development & Build Commands
- Environment Variables
- Developer Tools (100% In-Browser)
- Content Management (MDX)
- Google AdSense Monetization Setup
- Google Analytics & Search Console Setup
- SEO Architecture & Structured Data
- Deployment Architecture (Cloudflare Pages & Vercel)
- Future Roadmap
Modern software engineers spend hours navigating bloated forums, paywalled documentation, and obsolete StackOverflow answers to fix compile-time exceptions and environment bugs.
DevFixHub provides:
- 50 Complete Developer Error Fixes: Root causes, terminal commands, and copyable code solutions across Spring Boot, Java, React, Next.js, Angular, Node.js, Python, Docker, Kubernetes, Git, and SQL.
- 30 Practical Programming Tutorials: Step-by-step guides with architecture tips and best practices.
- 10 Free Online Developer Tools: Completely private, client-side utilities with zero server transmission.
- Fast Global Search (βK): Instant keyboard-driven search indexing errors, tutorials, and tools.
- AdSense-Ready Architecture: Layout-shift-free ad slots adhering strictly to Google publisher policies.
- β‘ Blazing Fast Performance: Static generation (SSG) with instantaneous page transitions.
- π Privacy Guarantee: Sensitive strings, tokens, JSON, and regex never leave the client browser.
- π Dark / Light / System Mode: Anti-FOUC theme switching respecting modern CSS
color-scheme. - π± Fully Responsive: Pixel-perfect typography and controls tested from 320px mobile to 1440px desktop.
- π Comprehensive SEO: Dynamic Next.js Metadata API, dynamic
sitemap.ts,robots.ts, and JSON-LD schemas (TechArticle,WebApplication,BreadcrumbList,FAQPage). - π‘οΈ Built-in Security: Hardened HTTP headers (
X-Content-Type-Options,X-Frame-Options,Referrer-Policy), input sanitization, and no client-side secret exposure.
- Framework: Next.js 15 (App Router)
- UI Library: React 19
- Language: TypeScript (Strict Mode)
- Styling: Tailwind CSS with custom design tokens
- Icons: Lucide React
- Content Engine: Local Markdown/MDX with typed frontmatter
- Testing: Vitest unit test suite
DevFixHub/
βββ app/
β βββ layout.tsx # Theme bootstrap, GA4 & AdSense scripts
β βββ page.tsx # Homepage with hero, tools, errors, tutorials
β βββ not-found.tsx # 404 page with navigation fallbacks
β βββ sitemap.ts # Dynamic sitemap (all 100+ routes)
β βββ robots.ts # Search crawler rules
β βββ errors/
β β βββ page.tsx # Directory of all 50 error fixes
β β βββ [slug]/page.tsx # Detail fix page with code and FAQ
β βββ tutorials/
β β βββ page.tsx # Directory of all 30 tutorials
β β βββ [slug]/page.tsx # In-depth architectural tutorial page
β βββ tools/
β β βββ page.tsx # Grid of all 10 browser tools
β β βββ [slug]/page.tsx # Interactive tool runner + guides
β βββ categories/
β β βββ [slug]/page.tsx # Category hub (Spring Boot, React, Docker...)
β βββ search/
β β βββ page.tsx # Dedicated search results with filters
β βββ about/page.tsx # Mission and philosophy
β βββ contact/page.tsx # Contact form and feedback
β βββ privacy-policy/page.tsx # GDPR/CCPA & AdSense compliant policy
β βββ terms/page.tsx # Terms of service
β βββ cookie-policy/page.tsx # Transparent cookie disclosure
βββ components/
β βββ Navbar.tsx # Responsive navbar + mobile drawer
β βββ Footer.tsx # Multi-column footer with legal links
β βββ SearchBar.tsx # Search input launcher
β βββ SearchModal.tsx # Cmd/Ctrl + K command dialog
β βββ ThemeToggle.tsx # Dark / Light theme toggle
β βββ AdPlaceholder.tsx # Banner, in-article, and sidebar ad slots
β βββ CodeBlock.tsx # Syntax container with copy button
β βββ CopyButton.tsx # Tooltip copy feedback button
β βββ Breadcrumb.tsx # Schema.org breadcrumb navigation
β βββ ToolCard.tsx # Interactive tool card
β βββ ErrorCard.tsx # Error fix card
β βββ TutorialCard.tsx # Tutorial card
β βββ RelatedContent.tsx # Automated cross-linking
β βββ tools/ # 10 Browser-based tools
β βββ JsonFormatter.tsx
β βββ JsonValidator.tsx
β βββ Base64Encoder.tsx
β βββ Base64Decoder.tsx
β βββ UuidGenerator.tsx
β βββ TimestampConverter.tsx
β βββ UrlEncoder.tsx
β βββ UrlDecoder.tsx
β βββ RegexTester.tsx
β βββ MarkdownEditor.tsx
βββ content/
β βββ errors/ # 50 MDX error articles
β βββ tutorials/ # 30 MDX tutorial articles
β βββ categories/ # 12 JSON category descriptors
βββ lib/
β βββ types.ts # Typed TypeScript interfaces
β βββ content.ts # Content loader & cross-linking
β βββ tools.ts # Tool metadata registry
β βββ categories.ts # Category descriptors
β βββ search.ts # Search indexing & scoring engine
β βββ seo.ts # SEO metadata & JSON-LD schemas
β βββ utils.ts # Formatting & string utilities
βββ tests/
β βββ tools.test.ts # Vitest suite covering all 10 tools
βββ .env.example
βββ package.json
βββ tailwind.config.ts
βββ tsconfig.json
βββ LICENSE
βββ README.md
- Node.js 18.18+ or 20+ (Node 24 recommended)
- npm 9+
# 1. Clone repository
git clone https://github.com/lasithadilshan/DevFixHub.git
cd DevFixHub
# 2. Install dependencies
npm install
# 3. Configure environment
cp .env.example .env.local
# 4. Start local development server
npm run devVisit http://localhost:3000 in your web browser.
# Start Next.js development server
npm run dev
# Run Vitest unit tests for all 10 developer tools
npm run test
# Run TypeScript compilation check
npx tsc --noEmit
# Build production bundle
npm run build
# Start production server
npm run startCopy .env.example to .env.local and configure:
# Canonical site URL
NEXT_PUBLIC_SITE_URL=https://devfixhub.site
# Google Analytics 4 Measurement ID (leave blank to disable)
NEXT_PUBLIC_GA_ID=
# Google AdSense Client Publisher ID (e.g. ca-pub-XXXXXXXXXXXXXXXX)
NEXT_PUBLIC_ADSENSE_CLIENT=
# Social Media Links
NEXT_PUBLIC_GITHUB_URL=https://github.com/lasithadilshan/DevFixHub
NEXT_PUBLIC_LINKEDIN_URL=https://linkedin.comEvery tool processes inputs locally within the browser:
- JSON Formatter: Format (2 spaces, 4 spaces, tabs), minify, byte comparison, download .json, copy.
- JSON Validator: High-precision syntax validation with line and column coordinates.
- Base64 Encoder: Standard and URL-safe Base64 encoding with UTF-8 support.
- Base64 Decoder: Safe Base64 decoding with padding recovery and character checks.
- UUID Generator: RFC 4122 v4 generator (1, 5, 10, 20 items), uppercase and hyphen toggles.
- Timestamp Converter: Bi-directional epoch seconds/ms <-> ISO/UTC/Local dates + live clock.
- URL Encoder: Component vs Full URI percent-encoding.
- URL Decoder: Percent-decoding with query parameters inspector table.
- Regex Tester: Live regex evaluation, flags (g, i, m, s, u), match counter, and capture group tables.
- Markdown Editor: Split-screen live preview, formatting toolbar, word count, .md and .html export.
Content is stored as local .mdx files in content/errors/ and content/tutorials/.
- Create
content/errors/<slug>.mdx:
---
title: "Docker Out of Memory Error (Exit Code 137)"
description: "Fix container exit code 137 by adjusting Linux memory limits and JVM heaps."
slug: "docker-out-of-memory-exit-code-137"
category: "Docker"
tags: ["docker", "memory", "devops"]
date: "2026-03-01"
author: "DevFixHub Core Team"
readingTime: "4 min"
errorCode: "Exited (137) 2 seconds ago"
---
# Docker Out of Memory Error (Exit Code 137)
...- Add the corresponding entry to
lib/data/errors-batch3.ts.
- Create
content/tutorials/<slug>.mdx:
---
title: "Mastering Next.js Server Components"
description: "Learn when to use React Server Components vs Client Components."
slug: "mastering-nextjs-server-components"
category: "React"
tags: ["nextjs", "react", "ssr"]
date: "2026-03-01"
author: "DevFixHub Core Team"
readingTime: "8 min"
difficulty: "Intermediate"
---
# Mastering Next.js Server Components
...- Add the entry to
lib/data/tutorials-batch2.ts.
DevFixHub includes production-ready AdSense architecture in components/AdPlaceholder.tsx:
- During development (or when
NEXT_PUBLIC_ADSENSE_CLIENTis unset), clean zero-shift placeholder boxes are shown. - In production, setting
NEXT_PUBLIC_ADSENSE_CLIENT=ca-pub-XXXXXXXXXXXXXXXXautomatically injects the Google AdSense script and renders responsive<ins class="adsbygoogle">ad tags. - Ad slots:
AdBanner: Horizontal banners (min-h-[90px]) between major content blocks.AdInArticle: In-article responsive slots (min-h-[250px]) placed below primary solution steps.AdSidebar: Sticky sidebar slots (min-h-[280px]) on desktop views.
- Google Analytics 4: Set
NEXT_PUBLIC_GA_ID=G-XXXXXXXXXXin environment variables. DevFixHub automatically tracks page views and navigation events without logging user tool inputs. - Google Search Console:
- Domain property verified via DNS TXT record on Cloudflare:
devfixhub.site. - Dynamic sitemap URL:
https://devfixhub.site/sitemap.xml. - Googlebot automatically discovers all 112 pages from
app/sitemap.tsandapp/robots.ts.
- Domain property verified via DNS TXT record on Cloudflare:
DevFixHub is deployed to Cloudflare Pages as a fully static Next.js export (output: 'export'):
- π Primary Production Domain: https://devfixhub.site
- π Cloudflare Edge URL: https://devfixhub.pages.dev
- π‘οΈ Edge Security: Native
public/_headersfile applied globally (X-Frame-Options: DENY,X-Content-Type-Options: nosniff,Referrer-Policy: strict-origin-when-cross-origin).
- Framework preset:
Next.js (Static HTML Export) - Build command:
npx next build - Build output directory:
out - Environment variables:
NODE_VERSION=20
For SEO continuity and backward-compatibility, the original Vercel project is preserved:
- π Vercel URL: https://devfixhub.vercel.app
- β‘ Behavior: Configured via
vercel.jsonwith a 308 Permanent Redirect sending all crawler and user traffic seamlessly tohttps://devfixhub.site/$1. This ensures zero broken links and preserves all existing Google search rankings.
Distributed under the MIT License. See the LICENSE file for more details.
Copyright (c) 2026 Lasitha Dilshan and DevFixHub Contributors. Free for developers everywhere.