The latest articles on DEV Community by swifttooly (@swifttooly). https://dev.to/swifttooly https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.us-east-2.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F4006974%2Ff90bc3ff-1778-4e03-ae90-56b61daae394.png https://dev.to/swifttooly en swifttooly Sun, 28 Jun 2026 20:35:00 +0000 https://dev.to/swifttooly/why-i-built-50-browser-based-tools-with-zero-backend-3cg1 https://dev.to/swifttooly/why-i-built-50-browser-based-tools-with-zero-backend-3cg1 <p>For years, every time I needed to merge a PDF or compress an image online, I had to upload my private files to some random server and just hope they got deleted. That always felt wrong.</p> <p>So I started building small tools that do everything in the browser — no upload, no backend, no database. The files never leave the user's device. I ended up with 50+ of them, and I want to share what I learned about going fully client-side.</p> <h2> Why client-side? </h2> <p>Three big wins:</p> <ul> <li>Privacy: the user's files never touch a server. Nothing to leak, nothing to store, nothing to comply with.</li> <li>Cost: no server means no hosting bill that scales with traffic. A static site can handle millions of users.</li> <li>Speed: no upload/download round-trip. The work happens instantly on the user's machine.</li> </ul> <h2> The browser can do more than people think </h2> <p>Most "simple" tools don't actually need a server. Modern browser APIs cover a huge amount:</p> <ul> <li>Canvas API — resize, crop, compress, and convert images entirely in memory.</li> <li>File API + Blob — read user files and trigger downloads without ever uploading.</li> <li>Web Crypto API — hashing (SHA-256, etc.) natively, no library needed.</li> <li>Libraries like pdf-lib and pdf.js — full PDF manipulation (merge, split, rotate) on the client.</li> </ul> <p>For example, compressing an image is just: read the file → draw it to a canvas → re-export at a lower quality → download the blob. No server in the loop.</p> <h2> What does NOT work client-side </h2> <p>Being honest about the limits, because this matters:</p> <ul> <li>Downloading videos from YouTube/TikTok — blocked by CORS, needs a server.</li> <li>Anything needing live data (real-time currency rates, etc.) — needs an API.</li> <li>Heavy video transcoding — technically possible with WASM but painful and slow.</li> </ul> <p>Knowing what <em>can't</em> be done client-side saved me from shipping broken tools.</p> <h2> The result </h2> <p>I put all of this into <a href="https://swifttooly.com" rel="noopener noreferrer">[SwiftTooly]</a> — a free collection of browser-based tools (PDF, image, text, QR, converters, dev utilities). Everything runs locally, no sign-up.</p> <p>Happy to answer questions about any of the implementations — the image and PDF stuff especially has some fun edge cases.</p> <p>What other tools do you think genuinely don't need a backend?</p> privacy showdev sideprojects webdev