Why I Built ToolCMB: A Free, Privacy-Focused Collection of Online Tools

Hiếu Nguyễn Trung — Mon, 28 Sep 2026 08:46:48 +0000

There are many small tasks we perform online every day:

Compressing an image.

Converting a HEIC photo to JPG.

Merging PDF files.

Formatting JSON.

Calculating a mortgage payment.

Generating a QR code.

Converting one file format into another.

For a simple task, installing desktop software or creating an account can sometimes feel like overkill.

That's the idea behind ToolCMB — a collection of free online tools designed to make these everyday tasks faster and simpler.

What is ToolCMB?

ToolCMB is a growing collection of browser-based utilities covering several practical categories:

Image tools
PDF tools
File converters
Developer tools
Calculators
QR and barcode tools
Web and SEO utilities

The goal isn't to create hundreds of random tools.

Instead, I'm building tools around real workflows that people repeatedly encounter at work, during development, while managing documents, or when working with images and files.

Image Tools

Images are one of the first areas of ToolCMB.

Common tasks include:

Compressing images
Resizing images
Cropping images
Converting JPG, PNG and WebP
Converting HEIC images
Optimizing images for websites

One example is HEIC to JPG conversion.

Modern iPhones commonly produce HEIC images, but JPG is still widely supported across websites, applications and other systems.

A dedicated converter makes the workflow simple:

Select HEIC
↓
Convert
↓
Download JPG

No complicated image editor is required.

PDF Tools

PDF is another major category of ToolCMB.

PDF files are everywhere — documents, invoices, reports, applications, forms and business files.

Some of the PDF workflows I'm building around include:

Compressing PDF files
Merging PDF documents
Splitting PDF files
Extracting PDF pages
Converting PDF pages to images
Converting images to PDF
Converting PDF and image formats

The goal is the same as with the image tools:

make a common file operation available directly in the browser.

For example, if someone needs to combine several documents into a single PDF, the workflow should be straightforward:

Select files
↓
Arrange pages
↓
Merge
↓
Download PDF

For many everyday tasks, that's all the user needs.

Developer Tools

ToolCMB also includes utilities for developers.

Some of the areas I'm focusing on include:

JSON formatting
JSON validation
JSON minification
Base64 encoding and decoding
URL encoding and decoding
UUID generation
Regex testing
Timestamp conversion
HTML/CSS formatting
SQL formatting

These are small tools, but they can save a surprising amount of time.

A developer shouldn't need to install an application every time they simply want to format a JSON response or decode a Base64 value.

Calculators and Converters

Another category is calculators.

Rather than focusing only on generic mathematical calculations, ToolCMB is designed to cover practical use cases.

Examples include:

Percentage calculations
Age calculations
Date calculations
Time calculations
Discount calculations
Tip calculations
Loan calculations
Mortgage calculations
Compound interest calculations

For financial calculators in particular, the goal is to make the result understandable rather than simply returning a number.

For example, a mortgage calculator can show more than the monthly payment:

Monthly Payment
Total Interest
Total Cost

This gives users more context when evaluating the result.

QR and Barcode Tools

QR codes have become part of everyday life.

Restaurants use them for menus.

Businesses use them for websites and contact information.

People use them for Wi-Fi access, events and sharing links.

ToolCMB is also expanding into QR and barcode utilities, including use cases such as:

URL QR codes
Text QR codes
Wi-Fi QR codes
vCard QR codes
Email QR codes
Barcode generation

The intention is to keep these tools simple: enter the information, generate the code, and download it.

Privacy-First Browser Tools

One of the principles behind ToolCMB is to use browser-side processing whenever it makes technical sense.

This is particularly interesting for files.

Imagine someone needs to compress an image containing personal information.

If the operation can be performed locally in the browser, the file doesn't necessarily need to be uploaded to a remote server.

The basic architecture can look like this:

User
↓
Browser
↓
JavaScript
↓
Process locally
↓
Download result

This approach can also reduce unnecessary server-side processing.

Of course, browser-based processing isn't suitable for every operation. Some tasks require backend processing.

The principle is simply:

When a task can safely be completed locally, don't send data to a server unnecessarily.

That's an important direction for ToolCMB.

Why build another tools website?

There are already many established online utility platforms.

I'm not trying to compete by simply creating another huge directory of random tools.

The idea is to build a platform around a few principles:

Useful

Each tool should solve a real problem.

Simple

A user should be able to understand the workflow immediately.

Fast

Small tasks shouldn't require complicated software.

Privacy-conscious

When technically possible, data can be processed directly in the browser.

Free to use

The core utilities are designed to be accessible without requiring an account for every simple operation.

Building ToolCMB incrementally

I'm building ToolCMB incrementally rather than trying to launch hundreds of utilities at once.

The roadmap revolves around several major areas:

IMAGE
↓
PDF & FILES
↓
DEVELOPER
↓
CALCULATORS
↓
QR / BARCODE
↓
WEB / SEO

Each category can then grow according to actual user needs.

This also creates an interesting technical challenge.

A simple image converter may be almost entirely browser-based.

A PDF workflow may require different processing techniques.

A developer utility can often run entirely in JavaScript.

A calculator may require nothing more than carefully designed formulas and a good interface.

So although these tools look simple from the user's perspective, building a useful utility platform involves quite a few interesting engineering decisions.

The technical side

For browser-based utilities, technologies such as JavaScript, Web Workers, browser APIs, WebAssembly and client-side file processing can make it possible to perform surprisingly complex operations without sending every piece of data to a backend.

A simplified image-processing workflow might look like:

File API
↓
Read file
↓
Web Worker
↓
Process image
↓
Create Blob
↓
Download

This architecture is particularly useful for tools where the user's file doesn't need to leave their device.

It can also help keep infrastructure requirements lower as usage grows.

What I'm building next

ToolCMB is still evolving.

The current direction is to continue improving the existing utility categories while adding tools that solve specific, repeatable problems.

Some of the areas I'm particularly interested in include:

More image conversion tools
More PDF utilities
File conversion
Developer utilities
Financial calculators
QR and barcode tools
Website and SEO utilities

Rather than creating tools simply for the sake of increasing the number of pages, I'd rather build fewer tools that people actually find useful.

Try ToolCMB

If you regularly work with images, PDFs, files, code or calculations, you can explore the tools here:

Visit ToolCMB

I'm also interested in hearing from other developers:

What small online tool do you find yourself searching for repeatedly?

It might be something simple — a converter, formatter, calculator, PDF utility or developer tool.

Those small repetitive problems are exactly the kind of problems I'm interested in solving with ToolCMB.

DEV Community: Hiếu Nguyễn Trung

Why I Built ToolCMB: A Free, Privacy-Focused Collection of Online Tools