ZentoMedia
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Apps, websites, and web tools

Creative Digital Solutions

ZentoMedia is an independent studio building mobile apps, websites, and web tools that aim to be simple, useful, and easy to use.

Explore Our AppsTools

Mobile Apps

Building Android and iOS apps that are smooth, reliable, and easy to use.

Web Development

Creating websites and web applications that are fast, clear, and practical.

Product Design

Turning ideas into digital products with a practical, user-focused approach.

Featured Apps

Products built and maintained by ZentoMedia.

Toán Vui Zento Logo
Latest update: Version 1.0.7 (Build 8)

Zento Fun Math

Play Smart - Learn Fast

Train your brain with colorful math games: Learn Table, Option Quiz, Input Quiz, True/False, Find Missing, and Duel mode.

Explore Our AppsGet it on Google Play
Zento Reader Logo
Chrome Extension • v1.1.0

Zento Reader: Smart TOC & Dark Theme

Ergonomic Eye Care & Smart Floating TOC

Auto-extracts headings (H1–H6) into a floating outline with 4 WCAG AAA 15:1 eye-care themes. 100% Client-side & Zero tracking.

Explore & PricingAdd to Chrome — Free
Browser Tools by ZentoMedia

Useful browser tools for everyday developer work.

Decode, transform, inspect, and generate data directly in your browser. No signup, no install, and no need to leave the page.

Binary inspection
Live

ASN.1 Lens

Inspect BER and DER structures directly in the browser with format detection, a readable tree view, and zero server round-trips.

Client-sideNo signupFast utilityFile upload
  • Accepts PEM, Base64, Hex, and uploaded files.
  • Detects the input format and normalizes the payload before parsing.
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URL transformation
Live

URL Encode / Decode

Encode or decode URLs, query strings, and parameter values directly in the browser.

Client-sideNo signupFast utility
  • Handles full URLs, query strings, and individual parameter values.
  • Useful for debugging redirects, callback URLs, and encoded request data.
Use this tool
Base64 transformation
Live

Base64 Encode / Decode

Convert UTF-8 text to and from Base64 locally in the browser without losing Unicode characters.

Client-sideNo signupFast utility
  • Uses UTF-8 aware helpers for readable text, not ASCII-only shortcuts.
  • Good for payload samples, test data, tokens, and quick debugging loops.
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HTML transformation
Live

HTML Entity Encode / Decode

Escape or unescape HTML entities such as <, >, &, quotes, and apostrophes without leaving the page.

Client-sideNo signupFast utility
  • Escapes and unescapes common HTML entities for safe copy and inspection.
  • Useful for content fields, snippets, email templates, and rendered text checks.
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JSON inspection
Live

JSON Decode Tree

Parse JSON into an expandable tree, unwrap JSON string layers, and decode nested fields locally in the browser.

Client-sideNo signupFast utility
  • Parses valid JSON objects and arrays into an expandable local tree.
  • Automatically unwraps JSON strings when the parsed result is still JSON text.
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Identifier generation
Live

GUID / UUID Generator

Generate batches of UUID v4 values in the browser with flexible formatting, Base64 variants, and copy-ready output.

Client-sideNo signupFast utility
  • Generates 1 to 1000 UUID v4 values using the Web Crypto API.
  • Supports canonical text, braces, uppercase, quotes, commas, and batch-friendly output.
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2FA generation
Live

2FA / TOTP Code Generator

Generate 2FA codes locally in your browser, import otpauth QR images, and keep shared secrets off third-party services.

Client-sideNo signupFast utilityFile upload
  • Supports plain secrets, optional label|SECRET lines, and otpauth://totp URIs.
  • Imports QR data from an image directly in your browser.
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Calendar reference
Live

Vietnamese Lunar Calendar

View a Gregorian month alongside the Vietnamese lunar calendar, convert dates both ways, and inspect Can Chi details directly in the browser.

Client-sideNo signupFast utility
  • Shows a full month grid with solar dates and matching lunar dates.
  • Converts Gregorian dates to Vietnamese lunar dates and converts lunar dates back to solar dates.
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Pronunciation learning
Live

English Pronunciation Tool

Look up a word or phrase, then open Oxford, Cambridge, YouGlish, and Google Translate quickly from one place.

Client-sideNo signupFast utility
  • Builds reliable Oxford, Cambridge, YouGlish, and Google Translate links from a normalized query.
  • Lets you choose a native translation language, with Vietnamese as the default.
Use this tool
Browse all tools

About ZentoMedia

Founder avatar drawing of D. Hung
Meet the founder

D. Hung

Founder • Solo Developer

ZentoMedia is a small independent studio that I build and run myself, with real joy in learning, making, and shipping useful products.

I focus on building mobile apps, websites, and small web tools that are simple, useful, and pleasant to use.

Mobile appsWebsitesSmall useful tools
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