# GEO & SEO Checker

SaaS platform for automated website analysis — 140+ checks across 6 categories, Lighthouse performance, GEO visibility, and AI-generated fix recommendations

Full-featured SEO audit engine with results in ~30 seconds. Built a monorepo from scratch: Next.js dashboard, Fastify API, isolated audit package, paywall system, and GPT-powered chat recommendations.

🔍 SEO Audit Engine

🤖 AI Recommendations

⚡ Lighthouse + GEO

💼 SaaS Platform

2025

Co-Founder, Lead Product Designer & Full-Stack Developer

Visit GEO & SEO Checker

140+

SEO Checks

~30s

Audit Time

Report Categories

350+

Commits

Project Overview

GEO & SEO Checker (geoseochecker.com) is a full-featured SaaS product for automated website analysis. The platform scans any URL in ~30 seconds and generates a detailed report covering technical SEO, Core Web Vitals, security & HTTPS, mobile-friendliness, GEO visibility (how the site appears in AI-powered search — Perplexity, ChatGPT, Gemini), and content structure.

Each detected issue is categorized as an Error, Warning, or Notice — and linked to an AI chat that generates specific, actionable recommendations. A unique Score Forecast shows current state, potential gain from quick wins, and full-fix projections all in one view.

Built the entire product solo — from architectural decisions and monorepo setup to UX details and deployment configuration across Railway, Vercel, Supabase, and Docker.

Audit Coverage

Technical SEO, Core Web Vitals, Security & HTTPS, Mobile, GEO Visibility (AI search), Content Structure

AI Integration

GPT-powered chat with automatic recommendation generation per detected issue. Plain-language explanations and code-style hints.

Monetization

3 paid plans ($15.99–$111.99/mo) — vs $99–$129+ for Semrush/Ahrefs. Feature gating, blurred sections, AI message limits.

Problem & Solution

The Gap in SEO Tools

—Enterprise tools (Semrush, Ahrefs) cost $99–129+/mo and are overkill for most sites
—Free checkers run surface-level checks with no explanation of root causes
—Google Search Console shows "symptoms" — not root causes or fixes
—No existing tool covers GEO visibility — how a site appears to AI-powered search (Perplexity, ChatGPT, Gemini)
—Audit reports list problems but don't generate specific, actionable fix recommendations

What GEO & SEO Checker Does Differently

140+ checks run in parallel, results appear live in ~30 seconds — no account required for initial results
GEO visibility analysis — unique category covering AI search engine presence
AI chat linked to every issue — specific fix recommendations with plain-language explanations and code hints
Score Forecast: current state + quick wins + full-fix potential in one view
Starting at $15.99/mo — 8–10× cheaper than enterprise alternatives

Monorepo Architecture

Frontend — Next.js

• Next.js (App Router)
• TypeScript
• Tailwind CSS
• shadcn/ui components
• Donut charts, sparklines
• Score Forecast UI
• Global search across findings
• Blurred paywall sections

API — Fastify

• Fastify (TypeScript)
• Parallel audit job orchestration
• GPT integration layer
• Auth & plan gating
• Webhook handling
• Docker deployment (Railway)

seo-checks Package

• 140+ individual SEO checks
• Error / Warning / Notice severity
• Playwright-based crawling
• Lighthouse runner
• GEO visibility checks
• Vitest test suite

Architecture Decisions

Isolated seo-checks package: Keeps audit logic decoupled from the API — easier to test, version, and reuse independently

Fastify over Next.js API routes: Long-running audit jobs need a persistent server process, not serverless functions

Docker on Railway: Audit runners need headless Chromium for Lighthouse and Playwright — containerization avoids environment drift

Supabase: Audit results, user plans, and AI chat history stored in PostgreSQL with RLS for per-user data isolation

6 Report Categories

Technical SEO

Meta tags, canonical URLs, structured data, robots.txt, sitemap, redirect chains, crawlability, indexability, hreflang — each surfaced with context and severity.

Core Web Vitals

Full Lighthouse integration: LCP, FCP, CLS, TTFB, TBT, Speed Index. Reports delivered as thematic blocks with scores and actionable breakdowns.

Security & HTTPS

SSL certificate validity, mixed content warnings, security headers (HSTS, CSP, X-Frame-Options), and HTTPS redirect configuration.

Mobile & Accessibility

Viewport configuration, touch targets, font sizes, tap spacing, and mobile Lighthouse scores — with mobile-specific performance data.

GEO Visibility (AI Search)

How the site appears to AI-powered search — Perplexity, ChatGPT, Gemini. Checks structured data, Open Graph, content authority signals, and citation-readiness.

Content Structure

Heading hierarchy, keyword density, content length, internal linking patterns, image alt attributes, and semantic HTML usage.

Score Forecast

A unique feature that goes beyond "you have X issues." Score Forecast shows three projections in one view so users can prioritize effort effectively:

Current State

The site's actual score right now, calculated from all 140+ checks

Quick Wins Potential

Score after fixing the highest-impact, lowest-effort issues — shows immediate ROI of easy fixes

Full-Fix Projection

Maximum achievable score if all issues are resolved — sets a clear ceiling and long-term goal

AI Chat & Paywall System

AI Recommendations (GPT)

Every detected issue is linked to a GPT-powered chat. On opening any finding, the assistant automatically generates a specific recommendation — plain-language explanation plus code-style hints grounded in the actual audit data for that URL.

• Auto-generated recommendation on issue open
• Multi-turn chat for follow-up questions
• Context includes the full audit result for that check
• Code-style hints for technical fixes

Paywall Architecture

Free tier lets users run audits and see all issues — AI recommendations and PDF export require a paid plan. Designed to show value before asking for payment.

• Feature gating at the API level (plan checked server-side)
• Blurred UI sections for locked premium content
• AI message limits per plan tier (50 / 200 / unlimited)
• Contextual upgrade prompts tied to the blocked feature
• Scheduled audits gated to Advanced and Unlimited plans

Pricing

Positioned as a high-value alternative to Semrush/Ahrefs ($99–129+/mo) — full audit capabilities at 8–10× lower cost.

Professional

$15.99/mo

• 1 website
• Full metrics across all categories
• AI-generated fixes
• 50 AI chat messages/mo
• PDF export
• GEO Score

Advanced

Unlimited

$111.99/mo

• Unlimited websites
• Full metrics across all categories
• AI-generated fixes
• Unlimited AI chat messages
• PDF export
• Daily / weekly / monthly scheduled audits

20% discount available on all yearly plans. 7-day money-back guarantee.

Technical Stack

Languages & Frameworks

• TypeScript (end-to-end)
• React / Next.js (App Router)
• Fastify (API server)
• Tailwind CSS + shadcn/ui

Infrastructure & Data

• Supabase (PostgreSQL + auth)
• Railway (Fastify API + Docker)
• Vercel (Next.js frontend)
• Docker (Chromium / audit runners)

Audit Tools

• Playwright (headless crawling)
• Google Lighthouse (Core Web Vitals)
• Custom seo-checks package

AI & Testing

• OpenAI GPT (recommendations)
• Vitest (unit tests for seo-checks)
• Playwright (E2E testing)

What I Built

Monorepo Architecture

Designed the full project structure: Next.js frontend, Fastify API, and a standalone seo-checks package. Each layer has a clear responsibility and can be developed and tested independently.

Audit Engine (140+ checks)

Built an audit engine covering all major SEO signal categories, run in parallel with results appearing live. Checks are modular — each is a typed function with a severity level, a description, and a fix hint. New checks can be added without touching the API or frontend.

Lighthouse & Core Web Vitals

Integrated Google Lighthouse for performance analysis, running inside Docker to ensure consistent Chromium environments across local and production. Reports LCP, FCP, CLS, TTFB, TBT and Speed Index.

Security & HTTPS Analysis

Built a dedicated security category checking SSL certificate validity, mixed content, HTTPS redirects, and security headers (HSTS, CSP, X-Frame-Options).

GEO Visibility Reports

Built a unique report category analyzing how well a site is positioned for AI-powered search (Perplexity, ChatGPT, Gemini) — covering structured data quality, Open Graph, content authority signals, and citation-readiness.

Score Forecast

Designed and built the Score Forecast feature showing three projections: current state, quick wins potential, and full-fix ceiling — giving users a clear prioritization framework at a glance.

AI Chat with GPT

Wired GPT-powered chat to every audit finding. On opening an issue, the assistant auto-generates a plain-language explanation with code-style fix hints. Follow-up questions supported. Message counts gated by plan tier.

SEMrush-style Dashboard

Designed and built the full dashboard: thematic report sections, donut charts for score visualization, sparklines, and global search across all findings.

Paywall & Pricing System

Implemented 3-tier plan gating at the API level, with blurred UI sections and contextual upgrade prompts. AI message limits, scheduled audit access, and PDF export all enforced server-side.

Deployment Pipeline

Configured the full deployment: Railway for the Fastify API (Docker), Vercel for Next.js, Supabase for data. 350+ commits from initial architecture to final UX polish.

Conclusion

GEO & SEO Checker is a complete SaaS product built end-to-end — from monorepo architecture and audit engine design to dashboard UX and deployment. It demonstrates the ability to ship a complex, multi-layer product independently: infrastructure decisions, full-stack TypeScript, AI integration, and a monetization system all working together.

Skills Demonstrated

• Monorepo architecture design
• Full-stack TypeScript (Next.js + Fastify)
• Audit engine & domain logic (SEO / Lighthouse)
• GPT integration with context-aware prompting
• SaaS paywall and plan gating
• Docker-based deployment configuration
• Data visualization (charts, dashboards)
• E2E and unit testing (Playwright, Vitest)

Delivered

140+ checks across 6 report categories, results in ~30s
Full Lighthouse, Security, and GEO visibility integration
AI-powered chat per issue (GPT) with code hints
Score Forecast (current / quick wins / full-fix)
3-tier paywall with scheduled audits and PDF export
Deployed on Railway + Vercel + Supabase (Docker)

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