{"slug": "i-built-120-free-online-tools-here-are-10-mistakes-i-d-never-make-again", "title": "I Built 120+ Free Online Tools. Here Are 10 Mistakes I'd Never Make Again.", "summary": "A developer built 120+ free online tools at DukoTools and shared 10 mistakes they made, including launching too late, ignoring boring tools, and failing to market. Key lessons include using browser APIs, Docker for cold starts, and avoiding unnecessary accounts.", "body_md": "Four months ago I decided to build a simple utility website.\n\nThe original plan was maybe 15–20 tools.\n\nInstead, I somehow ended up shipping 120+ tools covering PDFs, images, developers, students, finance, AI utilities, and a lot of niche calculators.\n\nLooking back, I made almost every mistake a solo developer can make.\n\nHopefully this saves someone else a few months.\n\n**1. Stop waiting for the \"perfect launch\"\n**\n\nHuge mistake.\n\nNobody cares how many features you have.\n\nPeople care whether you solve their problem.\n\nIf I started again, I'd launch after 10–20 tools and let users decide what to build next.\n\n**2. Boring tools get used more than clever ones\n**\n\nInstead, the most used ones were things like:\n\nSimple wins.\n\nPeople search for solutions, not engineering.\n\n**3. Niche tools are an SEO superpower\n**\n\nAlmost nobody builds things like:\n\nThe competition is almost zero.\n\nThose pages have become some of my favourites because they solve real problems.\n\n**4. Browser APIs are incredibly underrated\n**\n\nCompression.\n\nImage editing.\n\nQR generation.\n\nJSON formatting.\n\nRegex testing.\n\nUUID generation.\n\nPassword generation.\n\nCSV editing.\n\nAll of these can happen directly inside the browser.\n\nThat means:\n\n**5. Docker can save you from cold starts\n**\n\nMy AI background remover worked perfectly locally.\n\nProduction?\n\nEvery first request timed out.\n\nThe reason:\n\nThe U2Net model (used by rembg) downloaded on first request.\n\nAround 170 MB.\n\nThe fix?\n\nDownload the model during the Docker build instead.\n\nOne tiny change.\n\nMassive improvement.\n\n**6. Users hate unnecessary accounts\n**\n\nNo email.\n\nNo registration.\n\nNo \"Create an account to continue.\"\n\nPeople just use the tool and leave.\n\nThat's exactly what most utility websites should encourage.\n\n**7. Performance matters more than animations\n**\n\nUsers never mentioned them.\n\nThey did notice:\n\nSpeed is a feature.\n\n**8. Mobile users deserve first-class treatment\n**\n\nIf your utility only works nicely on desktop...\n\nYou've already lost a huge percentage of users.\n\nEvery tool I build now starts with mobile in mind.\n\n**9. Build things you personally need\n**\n\nOpen it on your desktop.\n\nScan a QR code.\n\nStart typing on your phone.\n\nThe text appears instantly.\n\nNo login.\n\nNo app.\n\nNo emailing yourself.\n\nIt wasn't built because someone requested it.\n\nIt solved a problem I had every week.\n\nThose are often the best products.\n\n**10. Marketing is part of building\n**\n\nIt doesn't.\n\nIf nobody knows your project exists...\n\nIt doesn't matter how clean your architecture is.\n\nBuilding is comfortable.\n\nMarketing is uncomfortable.\n\nUnfortunately, both are required.\n\n**Where the project is today**\n\nThe project has grown into DukoTools, a collection of 120+ free online tools.\n\nEverything is free.\n\nNo signup.\n\nMany tools work entirely in the browser, and the site can even be installed as a Progressive Web App for offline use.\n\nI'm now focusing on improving the existing tools based on real user feedback instead of endlessly adding new ones.\n\nIf you have a favourite online tool that doesn't exist—or one that could be significantly better—I'd genuinely love to hear about it.\n\nBuilding is fun.\n\nBuilding things people actually use is even better.", "url": "https://wpnews.pro/news/i-built-120-free-online-tools-here-are-10-mistakes-i-d-never-make-again", "canonical_source": "https://dev.to/talha_ramzan_3878156fea8c/i-built-120-free-online-tools-here-are-10-mistakes-id-never-make-again-k2p", "published_at": "2026-07-28 15:28:04+00:00", "updated_at": "2026-07-28 15:34:50.061382+00:00", "lang": "en", "topics": ["developer-tools", "ai-tools"], "entities": ["DukoTools", "U2Net", "rembg", "Docker"], "alternates": {"html": "https://wpnews.pro/news/i-built-120-free-online-tools-here-are-10-mistakes-i-d-never-make-again", "markdown": "https://wpnews.pro/news/i-built-120-free-online-tools-here-are-10-mistakes-i-d-never-make-again.md", "text": "https://wpnews.pro/news/i-built-120-free-online-tools-here-are-10-mistakes-i-d-never-make-again.txt", "jsonld": "https://wpnews.pro/news/i-built-120-free-online-tools-here-are-10-mistakes-i-d-never-make-again.jsonld"}}