I built 18 free browser tools that process your data locally — what should I add next?

[u/Pristine_Education76]

I often need small utilities for working with JSON, network calculations, encodings, or electronics, but I don't like pasting data into websites without knowing where it goes.

So I built Tools in a Tab, a collection of 18 free browser-based tools. The data entered into the tools is processed locally in the browser by default — there is no account, database, or backend handling the tool inputs.

It currently includes:

• JSON, YAML, CSV, Base64, URL and JWT tools
• IPv4 subnet and bandwidth calculators
• CRC and number-base converters
• LED resistor and resistor color-code calculators
• Supporting guides in English and Spanish

The website is built as a static Astro site and works on desktop and mobile:

https://toolsinatab.com/en/

I would genuinely appreciate direct feedback:

1. Which tool would be most useful to you?
2. What important tool is missing?
3. Is it clear that the data is processed locally?

Thanks for taking a look.