About brevtool
Our Mission
brevtool exists to prove that useful online tools don't need to compromise your privacy. The web has long relied on a trade-off: get a free tool, give up your data. Files uploaded to servers, accounts created just to download a result, email addresses harvested in exchange for access. We built brevtool to make that trade-off unnecessary.
Every tool on brevtool — from PDF mergers to mortgage calculators to image converters — runs entirely inside your browser. Your files and your inputs never leave your device. There are no servers receiving your data, no databases storing your documents, and no accounts to create. You get the result, and you get to keep your privacy.
How It Works
Modern browsers are remarkably capable computing environments. Through a technology called WebAssembly (WASM), browsers can execute near-native-speed code compiled from languages like C and Rust. This makes it possible to run sophisticated file processing — the kind that used to require a server — directly in the tab you have open right now.
brevtool's file tools use libraries like pdf-libfor PDF manipulation, the browser's native Canvas API for image processing, and ffmpeg.wasm — a full port of the industry-standard FFmpeg — for audio and video conversion. These libraries are loaded once into your browser and do all their work locally, reading your files from memory and writing the output back to memory, from which you download the result directly.
Calculators and text tools are even simpler: they are pure JavaScript computations that happen instantaneously in the browser without touching the network at all.
Free, With No Catch
brevtool is completely free to use — no premium tiers, no watermarks, no file size limits enforced to push you towards a paid plan. Every tool, every time, for anyone.
The site is supported by non-intrusive display advertising through Google AdSense. These ads do not access your files, do not track your tool usage beyond what any standard ad network sees (the page URL), and do not require you to interact with them to use brevtool. They are there, they are honest about what they are, and they keep the lights on without a paywall.
Built on Open Standards
brevtool is a Next.js application deployed on the edge. The frontend uses React server components for fast, SEO-optimized rendering and TypeScript throughout. Tool logic is encapsulated in isolated browser modules that are loaded on demand — so you only download the code you actually use.
Privacy is not an afterthought here — it is the foundational constraint around which the entire architecture is designed. If a tool cannot be built to work client-side, it does not ship. This constraint has the side effect of making the tools faster: there is no round-trip to a server, no queue to wait in.
We collect only aggregate page view analytics — no file contents, no tool inputs, no personal data about what you process. Your files never leave your browser.
Who Builds brevtool
brevtool is built and maintained by Khoa, a software engineer who has been working on browser-based document and image processing tools since 2024. The site grew out of a personal frustration: every “free online converter” demanded an email, an account, or quietly uploaded files to a server that could log, train on, or leak them.
The technical thesis behind brevtool is that modern browsers — paired with WebAssembly, the Canvas API, the Web Audio API, and ports of mature C/C++ libraries like FFmpeg, pdf-lib, and libheif — can match or beat server-based converters on speed and reliability while making the privacy story trivially verifiable: open DevTools, watch the Network tab, see no upload happen.
Source for the platform and individual tool implementations is published at github.com/khoanna. If you find a bug or have a tool request, file an issue there or reach out via the contact link in the footer.