free tools that run in your browser

Dev tools,
minus the drama.

Format JSON, decode a JWT, test a regex, convert a timestamp, make a test file. Everything runs in your browser, so what you paste stays on your machine. No account, no limits.

open json-format

tools: 28
folders: 7
sign-up: none

try-it.shruns in your browser

// type help, or tap a command below

~/devtoolshelf $ uuid

ee99c207-e300-42ac-85b4-a102dfc77a6f

~/devtoolshelf $ b64 hello world

aGVsbG8gd29ybGQ=

~/devtoolshelf $

Browse the toolbox

28 tools in 7 folders, press / to search

backend/

7 tools

Day-to-day backend chores: generating identifiers, formatting payloads, decoding tokens, working with timestamps and URLs. Each tool runs in your browser, so secrets and request bodies stay in the tab.

testing/

4 tools

Helpers for building test data and comparing expected with actual output, for contract tests, fuzzing inputs and hunting flaky regressions.

frontend/

3 tools

Colour conversions for Android, Flutter and CSS, image encoding for inline assets, and placeholder text.

data/

4 tools

Format and convert structured data: SQL pretty-printing, CSV and YAML to JSON and back, and a multi-format file inspector.

devops/

2 tools

Cron expressions and subnets, without the off-by-one mistakes that page someone at 3 am.

text/

2 tools

Reading, comparing and measuring text: word counts for drafts and side-by-side diffs for review.

typing-tests/

6 tools

Typing tests scored the way employers and exam boards score them: net words per minute, the US federal 40 WPM standard, keypad speed for data entry, and the SSC, RRB NTPC and CPCT skill tests in English and Hindi, with every rule taken from the official notice.

README.md

Why another developer tools site?

The web has plenty of online JSON formatters already, and most of them are fine. The reason DevToolShelf exists is consistency: the same layout, the same copy-to-clipboard behaviour and the same predictable URL structure across every tool. Switching between formatting JSON, decoding a JWT, generating fake users and validating a regex should feel like one app, not seven different ones in seven different tabs.

Each utility does one job. There is no import-account button, no signup modal, no pro version to format more than 1 KB. If you can paste it into a text box, you can use it.

Is the data I paste here safe?

The transformation tools (JSON formatter, Base64, hash generator, JWT decoder, CSV and YAML to JSON, regex tester and the rest) run as plain JavaScript inside your browser. Once the page has loaded you can disconnect from the internet and the tool keeps working. Fake data is generated locally too, so the synthetic identities you create never appear in any log.

How is it paid for?

The site shows contextual ads from Google AdSense, below the tools and never inside a tool's output. Read the privacy policy for the details, or the about page for how the project started.

Dev tools,minus the drama.