At some point, I realized I was pasting sensitive production data into tools I knew nothing about.
Every day, we use online developer tools like:
- diff checkers
- JWT decoders
- JSON formatters
They’re part of normal backend and frontend workflows. You Google one, open the first result, paste your data, get the output, and move on.
But when you slow down and think about it, a lot of these tools deal with sensitive information:
- JWTs with user IDs, emails, and roles
- production configs and environment values
- feature flags and API responses
- code snippets during reviews and debugging
Most online dev tools don’t clearly say:
whether your input is processed on the server
- whether it’s logged or stored
- how long it’s retained
- That uncertainty started to bother me.
Diff checkers and JWT decoders are used more than we admit
Two tools really pushed me to rethink this.
Diff Checker
I use diff checkers constantly during code reviews and debugging. It’s common to paste two versions of configs or logic that are close to production. Doing that on a random website never felt great.
JWT Decoder
JWT tokens often contain more personal or internal data than expected. Decoding them using an unknown online service is a quiet risk most of us accept without questioning.
These tools are essential, but trust matters when you’re using them daily.
What I wanted from a developer utility tool
I wasn’t trying to build a product. I just wanted a developer utility site I could trust.
A few non-negotiables:
- 100% browser-side execution
- no backend or API calls
- no ads or popups
- no accounts or logins
If I paste a JWT or compare two files, that data should never leave my machine.
- Why browser-only tools matter
- With browser-based dev tools:
- your data stays local
- nothing is sent to a server
- there’s no ambiguity about storage
This is especially important for:
- JWT decoding
- diff checking configs
- formatting API responses
- It’s simple, predictable, and safer by default.
So I built a small set of tools for daily use
I ended up building a clean set of privacy-first developer tools that run entirely in the browser. No tracking, no analytics surprises, and no ads.
I now use it daily for:
- diff checking
- JWT decoding
- quick JSON formatting
Eventually, I realized other developers might want the same thing, so I put it online.
I’m curious how others approach this
I’m not saying everyone should stop using existing tools. I’m genuinely curious:
Do you think about privacy when using online dev tools?
Do you prefer browser-only tools or self-hosted ones?
Are there developer utilities you use daily that feel overcomplicated or risky?
I’ve dropped the link in the comments to keep the post clean.
Would love to hear how others handle this.
Top comments (1)
devutil.dev/
looking forward for your feedbacks.