Tools that treat your data as none of our business

YamlBox exists because of an uncomfortable pattern in developer tooling: the files you most need help with — Kubernetes manifests with embedded secrets, JWTs carrying session claims, customer CSV exports — are exactly the files that most online tools ask you to upload to a server you know nothing about.

The alternative is not complicated. Modern browsers can parse YAML, read XLSX workbooks, diff JSON structures and generate code, all locally, all fast. The only reason many tools do it server-side is architectural habit. So every one of the 19 tools here runs client-side, which turns the privacy promise into an engineering fact rather than a policy statement: there is no upload endpoint because there is no server processing.

What that changes in practice

• Speed: no request per conversion, so results appear as you type and multi-megabyte files are bounded by your device, not a rate limit.
• Privacy: nothing is transmitted, logged or stored. You can verify with the browser network tab, or by going offline.
• Longevity: quiet, static pages served from an edge cache — cheap to run, so the tools stay free without aggressive monetisation.
• Honesty: error messages that name the line and column, feature lists that describe what the tool actually does, and no dark patterns around limits.

How the site is built

The site is static: Astro generates HTML at build time, Tailwind CSS v4 styles it, and a small amount of TypeScript powers each tool, loaded only on the pages that need it. Everything is served from Cloudflare’s edge network, which means the pages arrive from a data centre near you. There is no application server, no database, and no user account system — the entire architecture is a reflection of the privacy claim.

Principles

1. Do one job properly. Each tool is a focused utility with real error handling, not a mega-app with sixteen half-features.
2. No accounts, ever. A converter should not need your email address. Nothing on this site requires signup.
3. Accessibility is not optional. Keyboard navigation, visible focus, semantic HTML and screen-reader labels are part of the definition of done — not a later pass.
4. Explain the format. Tools are paired with guides that explain the underlying format, so you leave with understanding rather than a one-off fix.

Get in touch

Bug reports with a minimal failing example are the most valuable thing you can send. Feature requests are read and often built. Write to hello@yamlbox.com.