LeanDevKit

Free developer tools that run entirely in your browser. Draw architecture diagrams and flowcharts; format, validate, compare and convert JSON, YAML, TOML, CSV, XML, SQL and Protobuf text; decode Base64 and URLs; generate passwords, secret keys and hashes, and decode, verify and sign JWTs; and convert Unix timestamps, read cron expressions, test regular expressions and generate UUIDs. No account, and your documents never leave your computer.

Tools

• Diagrams: Flowchart maker, Architecture diagram tool, Network diagram maker, Microservices diagram, System design diagram, ER diagram tool, Sequence diagram tool, UML class diagram tool, Mind map maker, Gantt chart maker, Pie chart maker, Bar chart maker
• Formatter: JSON formatter and validator, YAML formatter and validator, XML formatter and validator, SQL formatter, CSV viewer, Base64 decoder, JSON to YAML converter, Diff checker
• Crypto: Password generator, Secret key generator, Hash generator, JWT decoder and verifier, JWT encoder
• Utilities: Unix timestamp converter, Cron expression explainer, Regex tester, UUID generator

Private by design

Every tool runs on your device. What you type, paste or open is processed in the browser and saved in the browser's own storage, so your documents never leave your device.

Your work is saved as you go, and stays in sync between the browser tabs you have open.

With your permission, we count anonymous visits with Google Analytics to learn which tools are used. What you type is never sent. See Privacy.

Questions

Is LeanDevKit free?

Yes. There is no account to create and nothing to pay.

Where is my work stored?

In your browser, on your computer. Clearing this site's data in the browser removes it, so download anything you want to keep as a file.

Does it work on Mac, Windows and Linux?

Yes, in any modern browser. Keyboard shortcuts follow your system: ⌘ on a Mac, Ctrl elsewhere.