What this is

CompoundVision is a suite of 36 free financial tools that run entirely in your browser. Free financial calculators with charts and a pro tier for portfolio tracking. No file you load and no value you type is uploaded to a server — every calculation, conversion or transformation happens locally on your device, and the result is visible only to you.

Why it exists

Most financial tools online today follow the same pattern: a slow page filled with intrusive ads, a paywall hiding the actually useful features, a forced signup, and an upload step that puts your data on someone else's server. After running into one too many of those, the operator (an independent developer based in Spain) started building self-contained alternatives one tool at a time. CompoundVision is the result for the financial category.

The design philosophy has stayed the same since the first commit: every tool must work without an account, without uploading anything sensitive, and without locking the obvious feature behind a "Pro" button. If a feature genuinely needs server-side computation, it is documented as such and the alternative is offered.

How it is funded

The free tier covers everything you can do in your browser without an account. The Pro tier (€7.99/month or €69.99/year) adds optional encrypted multi-device sync, live portfolio prices, DeFi/staking trackers, real-estate and expense tracking, tax tools and an ad-free experience. Pro is paid via Stripe; the free tier is paid for by display ads served by Google AdSense.

This means the site is sustainable without harvesting your data, gating tools behind a paywall, or pushing you toward a desktop app. If you find one of the tools genuinely useful and want to support continued development, the Buy Me a Coffee link in the footer is the most direct way.

Who is behind it

CompoundVision is built and maintained by Marco Bia, an independent developer based in Spain. The site is part of a small portfolio of utility web apps (CompoundVision for finance, AllYouNeed for general tools, JSONCraft for developers, OpenImages for image work, OpenPDF for PDFs, PingThat for networking). Each one shares the same private-by-default design.

If you would like to talk to a human about a tool, a bug or a feature you wish existed, the Contact page has a feedback form that lands in the operator's inbox within a few hours during EU working days.

Stack and openness

The site is built with Astro, Svelte 5 and Tailwind CSS 4, deployed on Cloudflare Pages, and uses no third-party trackers beyond aggregate Google Analytics 4 (with EU/UK consent gated to "denied" by default). Tool inputs never leave your browser, so there is nothing on a server to ask about under GDPR Article 15 — but if you want to know what we collect, the Privacy Policy spells it out fully.

Editorial independence

The advertising network (Google AdSense) does not influence which tools are built or how they work. There are no sponsored articles, no "best of" lists pushing affiliate links, and no editorial choices made to favour an advertiser. If a tool exists on the site, it is because it was useful enough to the operator to build and ship it.