How We Built CheckSEO.dev in 14 Days: Full Technical Case Study

Most SEO audit tools are built for agencies, not indie developers and startup founders. They cost $99-299/month, have steep learning curves, and generate 50-page reports full of jargon.

I wanted a tool that would give anyone — even someone who knows nothing about SEO — a clear, actionable report on what's wrong with their website and how to fix it. Something you could run in 30 seconds and actually understand.

So I built CheckSEO.dev. Here's exactly how it went from idea to live product in 14 days.

Frontend: React + TypeScript + Tailwind CSS. Our standard stack. No surprises here.

Backend: Supabase for auth, database, and edge functions. This let me skip building auth from scratch and focus on the core product.

Crawling: Firecrawl for web scraping and page analysis. It handles rendering JavaScript-heavy pages, which is crucial for auditing modern websites.

Hosting: Vercel for the frontend, Supabase edge functions for the API.

Key architecture decision: I made the audit engine stateless. Every audit request triggers a fresh crawl, analysis, and report generation. No caching of results (users want fresh data). The report is generated server-side and stored in the database for the user to revisit.

This stateless approach meant I didn't need to build a complex queue system or worker infrastructure. Simple, fast, scalable enough for the MVP.

Days 1-3: Scoping and wireframes. Defined the core user flow: enter URL → wait for crawl → see results. Designed the results page layout. Created the database schema (users, audits, audit_results).

Days 4-7: Core audit engine. Built the Firecrawl integration. Parsed HTML for meta tags, headings, image alt text, broken links, page speed metrics, and mobile responsiveness. The engine checks 40+ SEO factors.

Days 8-10: Dashboard and visualization. Built the results dashboard with color-coded scores, issue lists sorted by priority, and specific fix recommendations for each issue. Added PDF export for sharing reports.

Days 11-14: Polish and launch. Performance optimization. Bug fixes. Added rate limiting. Wrote the landing page. Set up analytics. Deployed to production.

Total development time: 14 days. Total cost: $0 (all tools used had free tiers).

We didn't wait for perfection. Here's the launch sequence:

Week 1 post-launch: - Submitted to Product Hunt (finished in top 20 for the day) - Posted on Hacker News (Show HN) - Shared on Twitter/X with a build thread - Submitted to Indie Hackers

Weeks 2-4: - Published 3 developer-focused blog posts targeting SEO keywords - Set up proper meta tags, sitemap, and schema markup - Added the tool to 15+ startup directories

Weeks 5-8: - Content marketing kicked in — blog posts started ranking - Word of mouth from early users - Got featured in 2 newsletter roundups

The key insight: launch early, distribute aggressively, and let SEO compound over time.

- 10,000+ SEO audits run by users worldwide - 3,000+ monthly active users - Page 1 rankings for 5 target keywords including "free SEO audit tool" - 4.8/5 average user rating based on in-app feedback - $0 in paid marketing spend — all growth was organic

The biggest lesson: a focused product that solves one problem well will always outperform a bloated product that does everything poorly.

CheckSEO.dev works because it's fast (results in 30 seconds), clear (no jargon), and free (no credit card required). Those three things drove all the growth.

If you're building a SaaS product, start with the smallest possible version that solves a real problem. Launch it fast. Let users tell you what to build next.