I built 121 free online file tools as a side project - here is what I learned

#webdev #productivity #sideprojects #showdev

After months of nights and weekends, I launched Filuni - a free online toolkit with 121 tools for PDF, image, video, audio, and document processing. No signup, no upload limits, no watermarks.

Why I built it

Every time I needed to merge a PDF or compress an image, I would land on a tool that either:

limited me to 2 free uses per day,
required an account for a 10-second task,
slapped a watermark on my file, or
wanted $12/month for basic operations.

So I built my own, and made it free.

What is inside

121 tools across 12 categories:

PDF: merge, split, compress, convert to Word/Excel/image, watermark, rotate, page numbers
Office: Word/Excel/PPT/HTML/Markdown/CSV to PDF
Image: compress, resize, crop, format convert, QR codes, EXIF viewer, watermark, collage
Video: compress, convert, extract audio, video to GIF
Audio: convert, compress, trim
Encryption: AES/RSA, hash generators, Base64, digital signatures
Developer: JWT decoder, regex tester, cron visualizer, cURL to code, JSON formatter/diff
Text / Color / Converters / Calculators: word counter, diff, palettes, WCAG contrast, units, timestamps, BMI, loans...

What I learned

Users hate signup walls for simple tasks. Removing all auth requirements was the single best UX decision.
Client-side processing wins trust. Most image/text/JSON tools run 100% in the browser (Canvas API, Web Workers) - files never leave your device. People notice and mention it.
SEO is king for tool sites. Every tool has its own landing page with FAQ and HowTo schema. Organic search is by far the biggest traffic source.
Multi-language support compounds. Filuni now ships in 11 languages (English, Spanish, Portuguese, German, French, Russian, Vietnamese, Korean, Japanese, Chinese Simplified & Traditional). Each locale opened a new market for the same codebase.

Tech stack

Nuxt 3 + TailwindCSS + PWA. FFmpeg handles video/audio on the server, LibreOffice (via jodconverter) does Office to PDF. Server-processed files are auto-deleted after processing.