Built HowToCSV, the Privacy-first CSV toolkit with WASM tech-stack
Just launched a browser-based data toolkit that processes CSV files entirely client-side - no uploads, full privacy.
🛠️ What I built:
A comprehensive CSV processing platform with 50+ tools for data cleaning, conversion, analysis, and visualization. Everything runs in your browser using DuckDB-WASM and Web Workers.
🔐 The privacy angle:
Tired of uploading sensitive data to random websites. This processes everything locally - your data never touches a server (for 90% of operations).
⚡ Tech highlights:
DuckDB-WASM for running SQL queries in browser
Web Workers for non-blocking heavy processing
Next.js 16 with programmatic SEO (750+ auto-generated posts)
Handles files up to 1GB with chunked processing
Multi-language support (5 languages)
💡 Key features:
Format conversion (CSV ↔ Excel ↔ JSON ↔ PDF)
Duplicate removal (exact + fuzzy matching)
Statistical analysis & EDA reports
SQL queries on CSV files
Data anonymization for GDPR compliance
AI chat assistant powered by Gemini
🎯 What I learned:
WASM bundle optimization is crucial (lazy loading saved me)
Client-side processing has real limits around 500MB-1GB
Programmatic SEO works for SaaS tools
Privacy-first is a real competitive advantage
Check it out: https://howtocsv.com
We have a long learn section with hundreds of articles about CSV and data on https://howtocsv.com/blog
Love the privacy-first approach! "Your data never touches a server" is such a strong selling point.
I took the same route with my app (SelfOS) - everything stored locally on device. Users really appreciate knowing their data stays theirs.
Congrats on the launch!
Love this approach. As someone building tiny browser tools, I’ve seen how much trust you earn when data never leaves the user’s device. DuckDB-WASM + Web Workers for real CSV work is a solid combo — privacy here isn’t a feature, it’s the product.
Smart choice going with DuckDB-WASM for this. Running SQL queries on CSV files client-side is a strong differentiator — most "CSV tools" websites feel like they're from 2010 and require uploading everything.
The programmatic SEO angle (750+ auto-generated posts) is interesting. How are you handling content quality at that scale? The risk with programmatic pages is thin content that ranks briefly then drops. Are you seeing stable organic traffic from those pages, or is it still too early to tell?
A few things I'm curious about:
The GDPR anonymization feature feels underappreciated. That alone could be a wedge into enterprise/compliance use cases if positioned right.