✅ No ads in tools  ·  No redirects  ·  Privacy-first

Your browser is
more powerful than you think.

Pure-JavaScript solutions running 100% in your browser: image compression, background removal, QR codes — free, no sign-up, and your files never leave your device. Plus a growing library of in-depth learning series with interactive demos right on the page: build neural networks, train a GPT-mini, simulate circuits, master SQL… For live events, SnapCast and ColorQuarium deliver real-time photo walls and ambient displays.

Explore tools ↓ GitHub →
6 Tools & services
0 Ads inside tools
100% Runs in your browser

Our Tools

SnapCast

☁️ Cloud service · Sign-up · Paid event plans

Real-time photo slideshow for live events

Host a live photo wall at weddings, parties, and conferences. Guests scan a QR code, snap a photo on their phone, and it appears on the big screen within seconds. Includes animated effects, remote control, and post-event gallery.

  • QR-code guest onboarding
  • Realtime Firestore sync
  • Animated slideshow effects
  • Remote control from phone
  • Post-event photo gallery
Open tool →
🎉 Live demo — photos update in real time

See it in action — right now

This is a real, live SnapCast event. Scan the QR code with your phone, take a photo, and watch it appear on the slideshow within seconds. No sign-up needed.

https://snapcast.js-tools.org/slideshow/XDXQK8?token=kypbsfpkdaxw67i67vql
QR code

Opens the guest upload screen on your phone

📸 Photo slots are limited. Want a private demo for your event?

✉️ support@js-tools.org

ColorQuarium

☁️ Cloud service · Sign-up · Paid plans

A living, generative aquarium of color and motion

ColorQuarium turns your screen into a calming, generative art display — and your phone into a remote control. Open the live view on a TV or monitor, then use your phone to change colors, themes, and motion in real time.

  • Real-time generative visuals
  • Mobile remote control via QR code
  • Customizable color themes
  • Smooth, ambient animations
  • No installs — runs in the browser
Open tool →
🐠 Live demo — control the display from your phone

See it in action — right now

This is a real, live ColorQuarium display. Scan the QR code with your phone to open the remote control and change what appears on screen in real time.

https://colorquarium.js-tools.org/srHTKBMckdPaXctAWsNw/live
QR code

Opens the remote control screen on your phone

Image Optimizer

✓ Free · Unlimited · No sign-up

Compress & convert images — 100% in-browser

Drag and drop images to compress them with zero quality loss. Supports JPEG, PNG, WebP, and HEIC from iPhone. Add watermarks, resize in bulk, compare before/after — all without uploading a single byte to any server.

  • JPEG & WebP output
  • Bulk processing with progress
  • Text & image watermarks
  • Before/after comparison slider
  • HEIC/HEIF support (iPhone photos)
Open tool →

QR Code Generator

✓ Free · Unlimited · No sign-up

Generate & customize QR codes — 100% in-browser

Create fully customizable QR codes with logo insertion, custom colors, gradient styles, and variable dot shapes. Perfect for links, Wi-Fi access, contact cards, and text — processed entirely locally on your device with zero data tracking.

  • Custom logo & branding support
  • Gradient & solid color styles
  • URL, Wi-Fi, vCard & text formats
  • Custom dot & corner shape styles
  • High-res SVG, PNG & PDF exports
Open tool →

Remove BG

✓ Free · Unlimited · No sign-up

Remove image backgrounds automatically — 100% in-browser

Erase backgrounds from your photos instantly using local AI neural networks. Supports JPEG, PNG, WebP, and HEIC. The entire process runs 100% locally in your browser sandbox with zero server uploads, keeping your data secure.

  • Local AI-powered segmentation
  • 100% private — no server uploads
  • Supports JPEG, PNG, WebP, and HEIC
  • High-resolution transparent PNG exports
  • Completely free with no limits or watermarks
Open tool →

Rubik & Pyraminx Solver

✓ Free · Fun · No sign-up

Solve a 3x3 Rubik's Cube or a Pyraminx — enter colors, get the moves

Enter your scrambled cube's or pyraminx's colors on an interactive 3D model and get a solution instantly. For the cube, pick the fast Kociemba algorithm (~20 moves) or a beginner-friendly layer-by-layer method with named stages — a fun, free break running entirely in your browser.

  • Two puzzles — 3x3 Rubik's Cube & Pyraminx
  • Kociemba (~20 moves) & beginner layer-by-layer methods
  • Interactive 3D model — drag to rotate, tap to paint
  • Scramble generator & solved-pattern presets
  • 100% free, no installation, works on any device
Open app →

Why js-tools?

Privacy First

Utility tools process everything locally in your browser — your files never leave your device, and we could not see them even if we wanted to.

Lightning Fast

No installation, no uploads. Open a tool and start working instantly. Processing happens right on your device.

Convenient

No account needed, no complexity. Just open, use, and go. Everything you need is right there.

Learn How These Tools Work

Our tools are built on open web technology — and we explain exactly how on our blog. Each series is a hands-on, in-depth course with runnable code, interactive visualizers and quizzes, written in both English and Vietnamese. Pick a track and start building.

AI

AI from Zero to Master

Build AI from scratch in vanilla JS — no API calls: gradient descent, your own autograd, MLP/CNN, Transformer, and a GPT-mini trained live in the browser.

AI Engineer

Practical AI Engineer

Transition from Web Development to AI. Master Python, PyTorch, MLP/CNN training, Self-Attention & Transformers, LLM APIs, advanced RAG pipelines, and stateful multi-agent systems offline.

AI Systems

AI Systems Engineering

Go beyond training a model: the real industrial lifecycle (data pipeline, distributed training, RLHF, red-teaming, rollout), hand-write your own agent framework, and orchestrate a multi-agent system with a blackboard and deadlock handling.

Vector DB

Vector Databases

Embeddings pipelines, geometric similarity metrics, hybrid storage, IVF indexing, HNSW graphs, Product Quantization, and a capstone local RAG search engine.

CPU

Computer Architecture

Explore the hardware stack running directly in your browser: logic gates, ALU, RISC-V pipelining, speculative execution, cache architectures, Apple Silicon UMA, and quantum qubits.

DSP

Digital Signal Processing

Every DSP algorithm hand-written in vanilla JS — no black-box AnalyserNode: sampling, FFT, windowing, FIR/IIR filters, pole-zero design you hear in real time.

Embedded

Embedded Systems

Bare-metal C on a self-built virtual MCU: registers, GPIO, interrupts, UART, ADC, DMA, up to a preemptive RTOS — no board required.

VLSI

VLSI & Digital IC Design

Master SystemVerilog RTL: 4-level abstraction, synthesis, simulation, place & route, STA — with interactive RTL Playground visualizer.

Electronics

Circuit Simulation

Learn electronics, analog filters, antennas, logic gates, sequential memory cells, and MCU register programming — completely in-browser.

Repair

Circuit Troubleshooting

Master hardware troubleshooting from block diagrams to circuit schematic tracing. Learn how to use a virtual multimeter for live DC voltage and cold resistance/diode measurements, test passive/active components, and repair linear & switched-mode power supplies.

SQL

SQL In The Browser

Real SQLite compiled to WebAssembly: relational model, JOIN, recursive CTEs, window functions, query optimizer, and internals — no server required.

Audio

Web Audio API

AudioContext, oscillators, filters, FFT analysis and spatial sound — hands-on with a real audio node graph.

Git

Git Internals

Object model, branches as pointers, merge/rebase, reflog recovery and remote collaboration — visualized commit graph.

DSA

Data Structures & Algorithms

AVL/Red-Black trees, pathfinding, dynamic programming and hashing — visualized step by step.

WebGPU

WebGPU & 3D Graphics

Modern GPU compute shaders, WGSL, real-time 3D rendering and interactive graphics.

CSS

CSS & Animation

Modern layouts, flexbox, grid, animations, transitions and responsive design mastery.

WebGL

WebGL & 3D Graphics

Shaders, the GPU pipeline, lighting and 3D math — real graphics programming in the browser.

C

C Programming

Pointers, memory management, data structures and Big-O — the foundations every programmer needs.

C++

Modern C++

RAII, move semantics, templates, the STL and smart pointers, explained from the ground up.

Canvas

HTML5 Canvas

2D graphics, animation, physics and particles — build interactive visuals from scratch.

Bash

Bash & Shell

Scripting, text processing, automation and defensive shell techniques for real-world work.

JS

JavaScript Deep Dive

The engine, the event loop, closures, prototypes and async — how JavaScript really runs.

Browse all articles →

Frequently Asked Questions

How do these tools process files entirely in my browser?

Our tools utilize cutting-edge web technologies like WebAssembly, HTML5 APIs, and Canvas. When you import an image, your browser processes it directly on your computer using local computing resources. No files are uploaded to any external server, ensuring maximum privacy and speed.

Are my files safe and private?

Yes. In our utility tools (Image Optimizer, Remove BG, QR Generator), all processing happens locally in your browser sandbox — your files never leave your device and we cannot see or store them. Event services like SnapCast and ColorQuarium do store the photos and settings you choose to share, handled under their own terms.

What image formats does the Image Optimizer support?

The Image Optimizer supports standard web formats including JPEG, PNG, WebP, SVG, and even HEIC/HEIF files directly from iPhones, making it easy to convert and compress iPhone photos for web use.

How does the SnapCast live slideshow demo work?

SnapCast uses a real-time database connection to instantly synchronize photo uploads. Guests scan a dynamically generated QR code using their smartphone, snap a photo, and the image is cast to the active live slideshow within seconds without requiring any app installations.

Is there a limit on file size or bulk processing count?

There are no artificial limits in our free utility tools. You can process as many files as your device memory can handle. Large batch sizes are processed sequentially to prevent browser tabs from freezing.