Developer Tools
Format JSON, decode JWTs, generate hashes, test regex, and clean up code without installing anything. Every tool on this page stays free to use, all the time.
All tools
Every tool below is free, works instantly, and needs no sign up.
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Related tool categories
Every category on ConvertNow, each one free and updated as new tools launch.
Understanding Developer Tools
What these tools are for, and how to get the most reliable result from them.
Built for everyday development work
Formatting, converting and encoding are small tasks that come up constantly while building software, yet they rarely justify installing another desktop app or command line package. This page brings the ones developers reach for most often into one place, ready the moment you open a browser tab, on any operating system.
From raw data to clean output
Data rarely arrives in the shape you need. These tools cover the common conversions between JSON, XML, YAML and CSV, along with Base64 encoding, hash generation and regex testing, so you can move from a messy export to something your code can actually use.
Practical for quick checks
Most formatting and conversion tools on this page run entirely in your browser tab, so the input you paste stays on your device rather than traveling to a server. Treat any online tool the way you would a shared computer and avoid pasting production secrets or credentials into any web based utility as a general habit.
Frequently asked questions
Straight answers to what people ask most about these tools.
Do these developer tools work offline?
Most run fully in your browser once the page has loaded, so they keep working even on a patchy connection. Tools that check a live server or domain need an active connection to return a result.
Is it safe to paste sensitive code or tokens?
Treat any online tool the way you would a shared computer. Formatting and encoding tools process input locally, but as a general rule avoid pasting production secrets, passwords or personal data into any web tool.
What is the difference between encoding and hashing?
Encoding, like Base64, is reversible, so you can decode it back to the original text. Hashing, like SHA256, is one way, meaning you cannot reverse a hash back into its original input.
Why does my JSON fail to format?
The formatter flags the exact line and character where the JSON breaks. This is usually a missing comma, an extra trailing comma, or an unescaped quotation mark inside a string value.
Can I use these tools on large files?
Browser based tools handle typical code and data files comfortably, but very large files, tens of megabytes and up, may slow down depending on your device. Split large files where possible.
Are new developer tools added regularly?
Yes. New utilities get added to this page on an ongoing basis, and this page always pulls the current list automatically, so you never need to check a separate changelog.
How to use these tools
The same simple flow works across every tool on this page.
Choose your tool
Browse the grid above or use the search box to jump straight to the utility you need.
Add your input
Paste code, text or a data file into the tool. No account and no arbitrary upload wall standing in your way.
Review the output
Most tools update as you type, so the formatted, converted or validated result appears right away.
Copy or download the result
Grab the output with one click. Nothing is retained after you close the tab.
Syntax and reference
Formulas, formats and quick references used across this category.
Basic JSON structure
{
"name": "ConvertNow",
"category": "developer",
"free": true,
"tags": ["json", "tools"]
}Base64 encoding example
Input: Hello World
Encoded: SGVsbG8gV29ybGQ=Regex quick reference
| \d | Any digit |
|---|---|
| \w | Any word character |
| ^ | Start of the string |
| $ | End of the string |
| + | One or more of the previous token |
| * | Zero or more of the previous token |
| ? | Makes the previous token optional |
Cron expression layout
* * * * *
min hr day mon weekday
Example: 0 9 * * 1 runs every Monday at 9:00 in the morningBuilt to be trusted, every time
No dark patterns, no forced accounts, and nothing you type is kept longer than it takes to give you an answer.
Nothing you enter is stored
Inputs are used only to generate your result, in that moment.
Free, with no catch
No sign up, no trial period, no hidden paywall on any tool.
Works on any device
Every tool is built to work on desktop, tablet and mobile.