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Mello.tools VS CodeUtil.dev

Compare Mello.tools VS CodeUtil.dev and see what are their differences

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Contents:
  1. ยป Base Details
  2. ยป Reviews
  3. ยป Alternatives

Mello.tools logo Mello.tools

Format JSON, generate passwords, convert colors, merge PDFs โ€” 122 utilities that run entirely in your browser. No accounts, no uploads, your inputs never leave the page.

CodeUtil.dev logo CodeUtil.dev

Fast, private developer tools in your browser. JSON formatter, Regex tester, Cron generator, and 17 more.
  • Mello.tools Homepage
    Homepage //
    2026-05-24

Mello is a directory of 122 utility tools that all run entirely in your browser. Format JSON, generate passwords, convert colors, merge PDFs, resize images, decode JWTs, calculate loans โ€” every tool runs as client-side JavaScript, with no server-side processing at any step.

The design rule is simple: no uploads, no accounts, your inputs never leave the page. That makes Mello safe for the everyday moments where you'd otherwise paste sensitive data into a free online tool โ€” a JWT containing a real session, a scanned passport, a photo with embedded GPS coordinates, a production database export. The catalog spans developer utilities, finance calculators, image and PDF tools, design generators, text utilities, password generation, hashing, and more. Free, no signup, no paid tier.

  • CodeUtil.dev Landing page
    Landing page //
    2026-03-09

CodeUtil.dev is a collection of 20+ browser-based developer tools. JSON formatter & validator, regex tester, cron expression generator, Base64 encoder/decoder, JWT debugger, URL parser, hash generator, and more. Everything runs client-side โ€” no data leaves your browser. No sign-up needed, just open and use.

Mello.tools features and specs

  • Tool count
    122 utilities across 10 categories
  • Browser-only architecture
    Every tool runs as client-side JavaScript; no server processing at any step
  • Privacy by design
    No uploads, no accounts; your inputs never leave the page
  • Free with no paid tier
    No usage limits, no premium features, no signup required
  • Developer tools
    JSON/XML/HTML/CSS/JS/SQL formatters, regex tester, JWT decoder, Base64/URL encoders, hash generator, UUID, cron parser, subnet calculator
  • Image tools
    Compression, resize, crop, format conversion (PNG/JPG/WebP/HEIC/AVIF), EXIF viewer, SVG optimizer, color picker
  • PDF tools
    Merge, split, rotate, image-to-PDF, PDF-to-image (JPG/PNG/WebP)
  • Design tools
    Color converter, palette generator, WCAG contrast checker, CSS box-shadow / border-radius / cubic-bezier / glassmorphism / gradient generators, favicon generator
  • Finance calculators
    Loan amortization, mortgage, ROI, compound interest, profit margin, break-even, VAT/sales tax, invoice PDF generator
  • Text utilities
    Case converter, word counter, text diff, line tools, slug generator, Lorem Ipsum, Morse translator, fancy text
  • Security tools
    Cryptographically random password generator (Web Crypto API), passphrase mode, password strength checker, MD5/SHA-1/SHA-256/SHA-512 hashing
  • Date & time tools
    Date math, Unix timestamp converter, age calculator, countdown, time zone converter, stopwatch, Pomodoro focus timer
  • Image format guides
    13 long-form articles on PNG vs JPG, WebP vs AVIF, HEIC conversion, social media image sizes

CodeUtil.dev features and specs

  • Free Online Developer Tools
    CodeUtil.dev provides a collection of free online utilities for developers, making it easy to access commonly needed tools without installing software or paying for subscriptions.
  • Wide Range of Utilities
    The site offers a variety of developer-focused tools such as formatters, encoders/decoders, converters, and generators, covering many common tasks developers encounter daily.
  • No Installation Required
    Being a web-based platform, developers can use the tools directly in their browser without needing to download or install any software, making it convenient and accessible from any device.
  • Simple and Clean Interface
    The site features a straightforward, easy-to-navigate interface that allows developers to quickly find and use the tool they need without unnecessary clutter or distractions.
  • Privacy-Friendly Client-Side Processing
    Many of the tools process data client-side in the browser, meaning sensitive code or data doesn't necessarily need to be sent to a server, which can be beneficial for privacy-conscious users.

Possible disadvantages of CodeUtil.dev

  • Limited Advanced Features
    As a collection of simple utilities, CodeUtil.dev may lack the advanced features and customization options that dedicated standalone tools or IDE plugins can offer for complex tasks.
  • Relatively Unknown Platform
    Compared to well-established alternatives like DevUtils, CyberChef, or similar developer tool sites, CodeUtil.dev has a smaller user base and community, which may mean less feedback-driven improvement.
  • Internet Dependency
    Being a web-based tool, it requires an active internet connection to access. Developers working offline or in restricted network environments cannot use the tools.
  • Limited Documentation and Support
    The platform may lack comprehensive documentation, tutorials, or dedicated support channels compared to more established developer tool platforms.
  • Potential Data Security Concerns
    While some tools may process data client-side, users must still trust the website with any data they input, and it may not always be clear which tools send data to a server and which do not.

Analysis of Mello.tools

Overall verdict

  • Mello.tools appears to be a useful collection of free online utilities, though as with any lesser-known tool site you should evaluate it based on your specific needs and always exercise caution with sensitive data.

Why this product is good

  • Offers a convenient set of online tools accessible directly from your browser with no installation required
  • Typically free to use, which lowers the barrier to entry for casual or one-off tasks
  • Web-based tools can be handy for quick conversions, formatting, or calculations on the go
  • Cross-platform accessibility means it works on most devices with a modern browser

Recommended for

  • Users who need quick, occasional access to online utilities without installing software
  • Developers or students looking for lightweight browser-based helper tools
  • People handling non-sensitive data who want fast, no-cost solutions
  • Anyone wanting to try out a tool before committing to a paid or dedicated alternative

Category Popularity

0-100% (relative to Mello.tools and CodeUtil.dev)

Mello.tools

CodeUtil.dev

Productivity
100 100%
Productivity
0% 0
Developer Tools
0 0%
Developer Tools
100% 100
Web Tools
100 100%
Web Tools
0% 0
Utilities
43 43%
Utilities
57% 57

Questions & Answers

As answered by people managing Mello.tools and CodeUtil.dev.

What makes your product unique?

Mello.tools's answer

Mello is the only utility-tools directory at this scale built around a strict no-server-processing rule. Every one of its 122 tools runs as JavaScript in your browser โ€” no uploads, no accounts, your inputs never leave the page. JWTs, photos with embedded GPS coordinates, contract PDFs, production data: none of it ever leaves your machine, because there is no server endpoint that could see it.

CodeUtil.dev's answer:

CodeUtil.dev runs entirely in the browser โ€” all processing happens on your device, so your data never touches a server. It bundles 20+ tools (JSON, regex, Base64, JWT, cron, hashing, and more) under one roof with zero sign-up. Just open the page and start working.

Why should a person choose your product over its competitors?

Mello.tools's answer

Most "free online tool" sites send your input to a server you don't operate. For utilities you reach for daily โ€” JWT decoders, image compressors, PDF mergers, password generators โ€” that means handing potentially sensitive data to a third party you have no agreement with. Mello solves this architecturally: the site is statically generated, there are no API routes, and the only thing the server returns is HTML and JavaScript. If your input matters at all, that's the difference.

How would you describe the primary audience of your product?

Mello.tools's answer

Developers, designers, small-business operators, and knowledge workers โ€” anyone who reaches for a "free online tool" several times a week. The privacy-first design especially fits people working with sensitive material (auth tokens, scanned IDs, financial data, unannounced creative assets) and people on slow or metered connections where avoiding uploads matters in practice.

What's the story behind your product?

Mello.tools's answer

Mello started from a recurring annoyance: needing to do something quick โ€” decode a JWT, compress a photo, format a JSON payload โ€” and realizing the easiest path was to paste sensitive data into a free site I had no relationship with. The "decoded client-side" claims in small text were untestable from outside. Browser-only seemed like the obvious right answer for these kinds of utilities, so I built it that way from the start. Mello shipped in May 2026 with 122 tools across 10 categories.

Which are the primary technologies used for building your product?

Mello.tools's answer

Next.js 15 (App Router) with full static export, React 19, TypeScript, and Tailwind CSS v4. Tool implementations use native browser APIs (Canvas, Web Crypto, FileReader, DOMParser) where possible, with carefully chosen JS libraries for the rest: pdf-lib and pdf.js for PDF handling, libheif compiled to WebAssembly for HEIC decoding, exifr for image metadata, marked and turndown for Markdown conversion, sql-formatter for SQL. Hosted on Cloudflare Pages as a fully static site.

User comments

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What are some alternatives?

When comparing Mello.tools and CodeUtil.dev, you can also consider the following products

Rune codes - Rune offers 100+ free online tools for PDF editing, image processing, text manipulation, file compression, OCR, and more. No signup required. Fast, secure, and easy to use.

CodifyFormatter.org - Free Online Tools like Beautify Code, Minifiy Code, Code Converter, Code Formatter, Viewer, Editor for Developer: JSON, XML, HTML, CSS, JavaScript, Java, SQL, CSV and Excel and String Tools

TinyWow - TinyWow provides free online conversion, pdf, and other handy tools to help you solve problems of all types.

DevToys - A collection of converters, formaters, encoders, generators and other tools for your Windows desktop.

IT Tools - IT Tools is a free and open-source collection of handy online tools for developers & people working in IT.

DuskTools.app - 150+ free browser-based developer tools - no sign-up, no tracking, no backend. JSON formatter, Base64 encoder, regex tester, JWT decoder, UUID generator, HTTP status lookup, MIME types, port reference, cron builder & more. Everything runs locally in

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