About KDevTool

KDevTool is a free collection of online tools for developers — JSON, SQL, YAML and XML formatters, encoders and decoders, hash and UUID generators, converters and more. Our goal is simple: give you the small utilities you reach for every day, in one fast, clean, ad-light place.

The project started because most existing tool sites are cluttered, slow, and quietly send whatever you paste to a server. We wanted the opposite — a site that respects your data and your attention.

Privacy first

Almost every tool on this site runs 100% inside your browser. When you paste JSON, a SQL query, a JWT or a password, that data is processed locally with JavaScript and is never uploaded to our servers. This is not just a promise — it is how the tools are built. It means you can safely use them with sensitive data, even offline.

Built for backend developers

While the site is useful for anyone, we pay special attention to tools that backend developers need day to day: SQL formatting and generation, JSON-to-Java and JSON-to-TypeScript converters, Spring Boot config helpers, JWT decoding, hashing and more. The tools come from real workflows, not a generic checklist.

Free and bilingual

Every tool is free to use, with no sign-up required. The interface is available in both English and Vietnamese so it serves a global audience as well as Vietnamese users. We keep advertising light and never let it get in the way of using a tool.

Feedback

This site is actively maintained and new tools are added regularly. If you spot a bug, need a tool we don't have yet, or have an idea, we would love to hear from you — see the Contact page.