{"slug": "i-built-79-browser-tools-in-three-weeks-with-ai-agents-and-none-of-them-touch", "title": "I built 79 browser tools in three weeks with AI agents, and none of them touch your files", "summary": "A developer built useeverykit.com, a collection of 79 browser-based tools across 14 kits, in three weeks using AI coding agents. All tools run entirely client-side, with a test suite that enforces zero off-origin requests to guarantee privacy. The project uses isolated Next.js apps on a single VPS, and the developer credits strict test gates for catching bugs that would have been missed by eye.", "body_md": "Three weeks ago I had an empty folder. Today useeverykit.com has 14\n\nkits and around 79 small tools, and the one rule behind all of them\n\nis that your files never leave your browser. This is the honest\n\nbuild log: what I made, how the client-side privacy actually works,\n\nand what it was like to have AI agents write most of it under strict\n\ntest gates.\n\nEvery \"free PDF merger\" or \"passport photo maker\" uploads your file\n\nto someone's server. For a passport scan or a contract, that always\n\nbothered me. The tasks themselves are small and mechanical, so there\n\nis no real reason the file has to leave your machine. I wanted a set\n\nof tools where the privacy claim is not marketing but something you\n\ncan verify in the network tab.\n\nEvery tool runs client side, and the interesting part is what that\n\ntook to keep honest:\n\nTo keep this from rotting over time, the test suite includes a\n\nnetwork sweep: it runs each file tool and asserts zero off-origin\n\nrequests. If a future dependency upgrade starts fetching something,\n\na test breaks instead of a promise.\n\nOne repository. Each kit is a standalone Next.js app behind nginx on\n\na single VPS, with its own process. That sounds heavier than one big\n\napp, and it is, but the isolation is the point: a bug or a heavy\n\nWASM crash in one tool can never take down the others, and each kit\n\ndeploys on its own. Consistency comes from a shared conventions file\n\nevery part of the repo obeys, rather than shared runtime code.\n\nAdding a new subdomain used to mean a DNS record and a certificate\n\nstep. Now a wildcard DNS record plus a deploy script that derives\n\nthe domain list from the registry and only calls certbot when a name\n\nis genuinely missing means adding a kit is one command.\n\nMost of the code was written by AI coding agents. The thing that\n\nmade that work was not the model, it was the discipline around it:\n\nevery unit had to pass typecheck, lint, tests, a production build, a\n\nreal-browser check at mobile and desktop widths, and the network\n\nsweep before it could merge. Agents that verify their own work,\n\nadmit when a test vector was wrong, and refuse to guess a file path\n\nare usable; agents left to run unchecked are not.\n\nA few real bugs the gates caught that I would have missed: a PDF\n\nguard that rejected on a single page failing to render, which would\n\nhave killed the whole page grid; signups from newer tools all being\n\nfiled under the wrong kit because of a hardcoded list; and that\n\npdf.js CDN fetch. None of these were obvious by eye. The tests found\n\nall of them.\n\nBuilding was the easy part, and honestly the comfortable part.\n\nGetting anyone to see it is the hard part, and it is not solved by\n\nbuilding more. If you are making something like this, spend at least\n\nas much energy on distribution and being honest in public as you do\n\non the code.\n\nThe tools are free. If you try one and something is clunky or\n\nmissing, I would genuinely like to know: useeverykit.com", "url": "https://wpnews.pro/news/i-built-79-browser-tools-in-three-weeks-with-ai-agents-and-none-of-them-touch", "canonical_source": "https://dev.to/ahadnawaz/i-built-79-browser-tools-in-three-weeks-with-ai-agents-and-none-of-them-touch-your-files-45hh", "published_at": "2026-08-26 11:54:46+00:00", "updated_at": "2026-08-26 12:14:53.758288+00:00", "lang": "en", "topics": ["ai-agents", "developer-tools", "ai-products"], "entities": ["useeverykit.com", "Next.js", "nginx", "certbot", "pdf.js"], "alternates": {"html": "https://wpnews.pro/news/i-built-79-browser-tools-in-three-weeks-with-ai-agents-and-none-of-them-touch", "markdown": "https://wpnews.pro/news/i-built-79-browser-tools-in-three-weeks-with-ai-agents-and-none-of-them-touch.md", "text": "https://wpnews.pro/news/i-built-79-browser-tools-in-three-weeks-with-ai-agents-and-none-of-them-touch.txt", "jsonld": "https://wpnews.pro/news/i-built-79-browser-tools-in-three-weeks-with-ai-agents-and-none-of-them-touch.jsonld"}}