· Szymon Berski · Portfolio · 2 min read
Uper SEO Auditor
Chrome extension for SEO specialists and developers. Provides real-time debugging of Web Vitals, Schema.org, GTM, and JS errors directly in Chrome Side Panel.
Professional SEO Tool for Developers
Chrome extension for comprehensive SEO analysis directly in browser Side Panel. Uper fills the gap between simple meta-tag readers and heavy crawlers, offering real-time debugging for modern SPA applications. Tool built by Senior Software Engineer with years of experience in technical audits and frontend optimization.
Core Features
Web Vitals with SPA Support
Continuous monitoring of LCP, CLS, and INP with native Soft Navigations support. Plugin correctly collects metrics in React, Next.js, and Vue applications, where traditional tools only measure performance during hard page reloads. Instant notification of metric degradation without launching Lighthouse.
Google Services and DataLayer Debugging
Verification of Google Tag Manager events, Consent Mode status, and detection of CSP or Ad-blocker blocks “on the fly”. DataLayer Inspector shows all events pushed to the data layer with every user interaction. Eliminates the need to launch heavy GTM debugging modes.
Design System and Tech Stack Detection
Automatic color extraction with export to Tailwind, UnoCSS, or CSS variables. Precise identification of frameworks (Vue.js, React, Next.js), UI systems (Bootstrap, Tailwind), CDN infrastructure, and analytics tools. Detailed list of fonts, their weights, and loading sources.
Content and Meta Tags Analysis
Realistic SERP preview with title and description length validation. Heading hierarchy analysis (H1-H6) and keyword density statistics (single words, bigrams, trigrams). AI support for content optimization directly in Side Panel.
Sitemap Analyzer
Built-in crawler for mass auditing hundreds of URLs from sitemap in seconds. Plugin automatically detects sitemap.xml and allows verification of HTTP statuses, meta tags, and response times. CSV export of results for further analysis or reporting.
Schema.org and Structured Data
Validation of JSON-LD, Microdata, and RDFa with built-in Schema.org definitions database. Detection of structural errors and missing properties required by Google Rich Results. Preview of Search Console rendering.
Side Panel as Command Center
Native Chrome Side Panel enables work without context switching. Ability to freely navigate the site, test purchase paths and forms with real-time metrics preview. One-click PDF report export.
Technologies
Vanilla JavaScript
Pure JavaScript with ES modules, no frameworks. Ensures small plugin size, fast loading, and full control over performance.
Chrome Extension Manifest V3
Latest Chrome Extension API version with Service Workers and improved security mechanisms. Side Panel API for better UX.
Native Browser APIs
PerformanceObserver for Web Vitals, MutationObserver for DOM change tracking, IntersectionObserver. Custom implementation without external dependencies.
Custom CSS Architecture
Modular CSS system with variables, components, and utilities. Optimized with PurgeCSS for minimal bundle size.
Schema.org Validation
Built-in Schema.org definitions database for JSON-LD, Microdata, and RDFa validation. Automatic updates from official sources.
Build Automation
Node.js scripts for build automation, versioning, and optimization. Archiver for packaging, PurgeCSS for CSS optimization.
The plugin is regularly updated with new features and available for free in Chrome Web Store.
