
JSONFormatter.org
OnlineDeveloperTool
DevCrate
JSONLint
JSON Formatter & Validator
CodeBeautify
DevsBox
30 free browser-based developer utilities: JSON formatter and diff, regex tester, JWT decoder, Base64, hashing, cron parser, YAML and CSV converters. No sign-up, and every tool runs entirely in your browser.

Beyond Compare
WinMerge
Meld
Araxis Merge
DiffMerge
P4Merge
Devart Code Compare
KDiff3 is a file and directory diff and merge tool which compares and merges two or three text...
Which is more popular?
Website, pricing, platforms and company facts side by side.
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| Website | dev-toolbox.io | github.com |
| Pricing | — | |
| Platforms | — | |
| Company | Startup from the United States · 1 - 9 employees · 2026 | — |
| Listed in |
In their own words, as submitted to SaaSHub.


DevToolbox.io is a collection of 30 developer utilities that run entirely in your browser. Formatters for JSON, HTML, CSS, SQL, XML and JavaScript; comparators for text, files and JSON; converters for YAML, CSV, colour, timestamps and number bases; encoders and decoders for Base64, URLs and JWTs;...
No description of kdiff3 yet.
What each product offers, as listed by its team.


Possible disadvantages
An editorial look at what each product does well and who it suits.


No analysis of Dev-Toolbox.io yet.
Overall verdict
Why this product is good
Recommended for
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110. Tools and Unitilities - KDiff3 tool to compare files and folders
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How often each product is chosen within a category, 0–100% relative to the other.


As answered by people managing Dev-Toolbox.io and kdiff3.
Dev-Toolbox.io's answer
Everything runs in your browser. Most online developer tools post your input to a server to process it, which makes them unusable for anything sensitive — API keys, access tokens, production records, client data. DevToolbox.io does the work locally, so there is nothing to upload and nothing to retain. The only thing that ever leaves the browser is a Share link you explicitly create.
Dev-Toolbox.io's answer
Three reasons. Privacy: your input never reaches a server, so you can paste a real JWT or a production payload without thinking about it. Breadth: 30 tools in one place, so you are not bouncing between a different single-purpose site for every task. No friction: no account, no rate limits, no ads interrupting the tool, and each tool is its own URL you can bookmark or link to directly.
Dev-Toolbox.io's answer
Working software developers, and anyone adjacent to them — QA engineers, data engineers, technical support staff and students. The common thread is someone who needs to format, convert, decode or compare something quickly, mid-task, and does not want to install anything or hand their data to a third party to do it.
Dev-Toolbox.io's answer
It started from the habit of searching for "json formatter" or "base64 decode" several times a week and landing on whichever ad-heavy site ranked that day, never knowing what happened to the data pasted in. DevToolbox.io was built to be the bookmark that replaces those searches: the same tools, in one place, that run in the browser and do not ask for anything.
Dev-Toolbox.io's answer
Next.js and React with TypeScript, styled with Tailwind CSS and deployed on Vercel. The editors are Monaco, the same editor component used by VS Code. Heavier work — parsing, diffing, formatting and minifying — runs in Web Workers so a large document never freezes the page. Established parsers do the real work rather than hand-written ones: Prettier and Terser for JavaScript, the yaml library for YAML, marked for Markdown and DOMPurify for sanitization.
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KDiff3 is a cross-platform diff and merge tool and works on Linux, macOS and Windows. It is a file and folder merge tool used to compare and merge two to three files and directoires.
KDiff3 is a merge program that works with Unix, Windows as well as Mac OS X platforms. It can compare or merge two or three text input files and directories and you choose to see the differences line by line or...
KDiff3 helps you merge files through a detailed process of spotting differences and then merging. Two or three text input files or directories can be compared or merged with the differences between every single line...
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Online JSON Formatter and JSON Validator will format JSON data, and helps to validate, convert JSON to XML, JSON to CSV. Save and Share JSON
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Beyond Compare allows you to compare files and folders.
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Free browser-based developer tools for JSON, JWT, Base64, UUID, hashing, timestamps, regex, XML, YAML and more. No signup required.
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WinMerge is an open source differencing and merging tool for Windows.
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Fast, free developer tools for JSON, JWTs, cURL, Base64, hashes, Shopify CSV, and UUIDs. Every tool runs locally in your browser.
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What is Meld? Meld is a visual diff and merge tool targeted at developers.
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