I Built 35+ Free Browser Tools as a Solo Dev
I've been building ToolsOnFire - a collection of 35+ free online tools. Video converters, AI voice separation, a sticker creator, markdown converter, and more.
I'm a solo developer from the UK based in Norway. No team, no funding. Just a frustration with paying subscriptions for simple tasks, so I built free alternatives.
*The Stack *
- Next.js 14 (App Router) with TypeScript - Firebase for auth and database
- Stripe for premium tiers
- Vercel for hosting The Key Decision: Process in the Browser Most of my tools process files entirely in the user's browser rather than on a server.
My Video to Gif Converter and Video to audio converter use FFmpeg.wasm - a WebAssembly port of FFmpeg.
This means files never leave the user's device. No uploads, no privacy concerns, and I don't pay for server compute.
The trade-off is browser memory limits. I had to add device detection to cap file sizes on mobile and optimise how large files are handled.
*AI-Powered Tools *
Some tools need real AI models:
Voice Separator and background music extractor - Splits recordings by speaker using Deepgram and Replicate. Useful for podcasts, interviews, and meetings.
Sticker Creator - Generates custom stickers with DALL-E 3, or removes backgrounds from photos client-side using an ONNX model.
*What I've Learned *
You have to try things to see if they work. My top 5 tools drive 90% of traffic, but I wouldn't have known which 5 without building all of them. Some tools I expected to be popular get no visits. Others I built on a whim end up surprising me.
SEO is the real challenge. Building the tools was the easy part. Organic traffic growth is still slow. If I could go back, I'd start writing content and building backlinks from day one.
*My Other Projects *Meeting Transcriber - Records and transcribes meetings with automatic speaker identification - Speech Assistant Tool - AI speech coaching with real-time feedback
I'm always building and experimenting with new tools. If something works, I double down. If it doesn't, I move on.
Would love to hear from anyone who's grown a tools site from zero - what worked for you?
Top comments (4)
The FFmpeg.wasm approach is such a good move. I've been looking at similar client-side processing for a side project and the memory management on mobile is definitely where things get interesting. Did you end up with any specific limits you settled on? Like "under 50MB is safe, over that you're rolling the dice"?
Also totally feel you on the "build 35, get traffic from 5" thing. I've learned this the hard way - just ship stuff and let users decide what matters. The tools you think will blow up usually don't, and some random utility you built in an afternoon becomes the hero.
For SEO: have you tried targeting more problem-based searches instead of just tool names? Like "how to remove vocals from song" instead of "vocal remover" - I've found those informational queries sometimes have less competition and convert into tool users pretty well.
Thanks for commenting and sharing 😊
What I have actually done is on desktop it will attempt to use client side first and if it can't then it will use the server. Then on mobile, anything under 100mb it will try client side first and fallback to server if it fails. Anything over 100mb on mobile and it just uses the server, skips client side entirely.
I have started adding some longtail keywords to see if that helps and I did recently add some funnel pages using different queries too. Probably too early to say if that works yet but hoping it will...
The 80/20 insight about top 5 tools driving 90% of traffic is something I've seen play out almost identically. I run a financial data site with 100,000+ programmatic pages across 12 languages, and the pattern holds — a small cluster of pages (specific tickers, specific languages) pulls disproportionate search impressions while thousands of others sit in Google's "discovered but not indexed" limbo.
Your point about SEO being the real challenge resonates hard. I'd have started content and backlinks from day one too. Building is the fun part; convincing Google your pages deserve to exist is the grind. One thing that's worked for me: writing about the process of building the site (lessons learned, architecture decisions, indexing battles) generates way more backlinks than the site itself does at this stage.
The browser-first processing approach with FFmpeg.wasm is a smart architectural call — no server costs scaling with usage, and the privacy angle is a genuine differentiator. Curious about your SEO strategy for individual tool pages: are you targeting long-tail queries like "convert video to gif online free" for each tool, or relying more on the domain building authority over time?
Thanks for the comment and the tips. You have a good point about the long tail keywords. I have used some in the body but I may try updating headers and meta tags... I could be using too competitive keywords. I do have an Insider page where I also post an Insider newsletter every Monday with lessons I have learned along the way whilst building the site and you are right those seem to get more interest than any of my other posts
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