There are some developer tools that are not complicated at all, but still manage to interrupt your flow every time you need them.
Base64 encoding and decoding is one of those for me.
When I am debugging an API response, checking a payload, testing a data URI, or looking at a config value that someone encoded, I usually do not want to open a terminal, write a quick snippet, or search for a random converter. I just want to paste the text, see the result, copy it, and move on.
So I built a small browser-based Base64 encoder and decoder for Tools Online:
https://toolsonline.run/base64
It does the basic thing: encode text to Base64 and decode Base64 back to text. But I tried to make the workflow feel less annoying:
- Real-time conversion while typing
- Encode/decode mode switching
- UTF-8 support, including CJK text and emoji
- One-click copy and paste
- Decode error feedback
- Local conversion history in the browser
One detail I wanted to make clear on the page is that Base64 is not encryption.
That sounds obvious, but I still see Base64 used in places where people treat "not immediately readable" as "secure". Base64 is just an encoding format. Anyone can decode it. If the data is sensitive, it needs real encryption, not a different text representation.
I also added a short explanation of how Base64 works: 3 bytes become 24 bits, those bits get split into 4 groups of 6 bits, and each group maps to the Base64 alphabet. Padding with = is added when the input length does not fit cleanly into groups of 3 bytes.
The implementation is intentionally simple. The conversion runs in the browser, so the text never needs to be sent to a server. For a tool like this, that matters more to me than adding extra features.
AI helped with the early checklist: edge cases, UX states, page copy, FAQ structure, and multilingual SEO content. The actual implementation still needed manual cleanup around TypeScript types, browser APIs, error handling, and keeping the UI consistent with the rest of the site.
It is a small tool, but I like small tools that remove repeated friction.
If you deal with Base64 often while debugging APIs or frontend data, you can try it here: