Shalom Karr
I engineer high-performance web applications and digital infrastructure.
Specializing in JavaScript, Supabase, and serverless architecture.
About Me
Hello, I'm Shalom Karr, a full-stack engineer and digital infrastructure specialist. I am driven by a passion for building robust, scalable applications that solve complex problems through meticulous engineering and intuitive design.
My technical expertise spans the entire development lifecycle. On the frontend, I craft highly responsive and accessible user interfaces utilizing modern JavaScript (ES6+), Tailwind CSS, and HTML5. On the backend, I leverage Python for powerful automation and data pipelines, alongside Supabase (PostgreSQL, Edge Functions, Auth) to deploy secure, real-time architectures.
Beyond traditional web development, I actively engineer solutions integrating Artificial Intelligence and complex automations. I thrive on identifying workflow bottlenecks and developing bespoke software tools that dramatically increase efficiency and utility.
Outside of client work, I'm a moderator on JTech Forums, a Jewish tech community focused on filtered phones, MDMs, and kosher device tooling. The moderation work — triaging filter-bypass discussions, category cleanup, helping members write better posts — has been a useful forcing function for thinking about online community design, content policy, and how a small staff keeps a busy forum signal-rich. Most of my GroupMe and Google Apps Script tutorials started as posts there.
I am a continuous learner in a fast-evolving industry, committed to thoughtful architecture and transparent communication. Whether I am building a clinical intake portal or a serverless proxy network, my ultimate goal is to deliver technical excellence and unparalleled user experiences.
My Technical Arsenal
Languages are a means, not a limit. These are the ones I've shipped production code in, and the tools I reach for around them.
Languages
Frontend & Frameworks
Backend, Data & Platform
Libraries, Data & AI
Tooling & Ecosystem
Practice Areas
Projects
A selection of tools, platforms, and infrastructure I have engineered.
SK Music
A fast, kosher, filtered YouTube music web client — search and stream a whitelisted catalog. Static Cloudflare Worker + client-side search, YouTube-iframe playback, installable PWA. Source is at https://github.com/Shalom-Karr/SK-Music
On Target ABA
ABA therapy to help your child succeed at home, at school… and at all times. Evidence-based, compassionate ABA therapy and autism evaluations for children. Most insurance accepted, and a low BCBA-to-client ratio so every kid gets the attention they deserve.
Shmuel Goldstein Coaching
Life & Relationship Coaching - A better life begins with how you live it. Honest conversation. Practical tools. The courage to create more meaningful relationships—with others and with yourself.
Every Child ABA
Every Child ABA is a professional website for an ABA Company. The site provides comprehensive information about their in-home ABA therapy services, which are tailored to each child's unique needs.
New Bridges ABA
Building Skills, One Step at a Time. Empowering Children with Autism to reach their full potential through ABA therapy. Nurturing the skills that help your child connect, grow, and thrive.
Baltimore Community Resource Network
A website for Baltimore Community Resource Network. Maryland residents browse plain-language guides for SNAP, Medicaid, WIC, and other assistance programs; admins edit every page — programs, FAQs, settings — through a side-by-side markdown editor with live preview and image upload. No build step, fully content-editable.
AddressIt LED
Website for Illuminated house number signs by Illumicor. When seconds count, be seen.
Torah Life Kollel
Beis medrash and kollel platform for Cleveland Heights, OH — dynamic davening schedule, shiurim listings, tax-deductible donation portal. Three sedarim with daily chaburos.
Khal Yereim
Synagogue platform for a Cleveland Heights congregation — halachic zmanim with a "Next Minyan" countdown, digital mikvah passes, Zelle donations, bilingual Hebrew/English, and a custom WYSIWYG print engine.
SpinCycle Rentals Cleveland
Skip the Laundromat - Rent Your Own Washer & Dryer. Premium all-in-one washer/dryer units starting at just $45/month. We handle the heavy lifting, installation, and maintenance so you don't have to.
CMH Luach
Multi-tenant halachic display boards for Orthodox shuls — per-tenant Supabase table prefixes, KosherZmanim, Open-Meteo weather, offline-capable service worker. Multiple live shul tenants on one codebase.
JTech Forums Moderator
Moderator at JTech Forums — a Jewish tech community focused on filtered phones, MDMs, and kosher device tooling. Day-to-day: triaging filter-bypass discussions, keeping categories clean, and helping members write clearer posts. The work is also where most of my GroupMe and Google Apps Script tutorials originated.
SK News Feed
Real-time news platform for the Yeshiva community — Supabase live feed, SMS alert subscriptions, community Chats + Sites directories, dual admin CMS panels.
Dinner Done Catering
A user-friendly e-commerce platform designed for high-volume catering sales. It allows customers to easily browse menus, build orders as guests, and securely check out. Built with a custom admin dashboard for staff to track live inventory, process invoices, and dynamically update website content, it’s the perfect end-to-end solution for managing a modern catering business.
The Hock Cleveland
A community news platform for Cleveland, providing weekly email blasts and real-time WhatsApp updates. It's the go-to source for local news, events, and deals, keeping the community connected and informed. It's a great example of how to use web technologies to create a simple and effective community news platform.
YTA Kollel
The ytakollel.com domain was set up to redirect users directly to the fundraising page for Kollel Tiferes Avigdor's 'Menorah Sweepstakes' campaign, . This ensures that potential donors can easily find and contribute to the campaign, which aims to raise $100,000 to support Rabbi Brog's Kollel.
Telshe Yeshiva
Rabbinical College of Telshe A premier Makom Torah dedicated to Amalas Hatorah, Hashkafa, and building the next generation of Bnei Torah.
SK Tools
A unified, privacy-first browser toolbox — PDF editor, video converter, audio toolkit, image utilities, VCF splitter, brute-force demo, calculator, and a BYO-key Claude chat. All processing happens in the browser, nothing is uploaded.
SK Games
A collection of classic browser games — chess (with minimax bot), checkers, connect four, unbeatable tic-tac-toe, wolf & sheep, and memory match. Pure HTML/JS, no installs or ads.
SK News
This is the website for SK News which is a text-based news service bringing updates and engaging discussions directly to your phone. We deliver accurate and reliable news sourced from a wide range of websites to ensure you have comprehensive coverage at your fingertips.
SK Brutes
An educational tool that demonstrates the concept of brute-force password cracking on a simple 4-digit code. It's a great way to learn about the importance of strong passwords and secure coding practices. It's a great example of how to use JavaScript to create a simple and effective educational tool.
Batch WMV to MP4 Converter
A tool for converting multiple WMV files to MP4 format. It's a fast, efficient solution for anyone who needs to convert video files for use on different devices or platforms.
SKFilter
A comprehensive tool for managing and configuring GroupMe group filters. It helps group administrators maintain a safe and positive chat environment by automatically filtering out unwanted content. It's an essential tool for any GroupMe group administrator.
RevealOS Unfilter Tool
A powerful tool designed to restore full internet access and app functionality to filtered, kosher-certified phones. It works by safely modifying system partitions, bypassing restrictions without compromising the device's integrity. It's a must-have tool for anyone who wants to unlock the full potential of their filtered phone.
Visual PDF Editor
A web-based tool for combining, reordering, and editing pages from PDFs and images. It's a simple, intuitive solution for managing and manipulating PDF documents without the need for expensive software. It's a great example of how to use JavaScript to create a simple and effective tool for PDFs.
YS Handymen
Handyman in Cleveland, OH - Small jobs. Big difference. We'll fix it. Fast. From a dripping faucet to the shelf that never got hung — Y.S. Handymen handles the repairs, replacements and odd jobs around your home that keep getting pushed down the list. Done right the first time.
Torah-Anytime-Downloader
Torah-Anytime-Downloader Desktop app + local proxy for TorahAnytime with a built-in seekable lecture downloader (MP4/MP3).
lockguard
Kernel-mode lockdown for Windows 11 focus machines. A Windows Filtering Platform firewall enforced at the driver layer, a Word-only application allowlist, and a Go watchdog and CLI supervising it. Written to resist a tech-savvy administrator rather than merely inconvenience one.
kiosk-exit-guard
A 7.9 MB single executable that turns a Windows machine into a locked kiosk: a WebView2 window, a low-level keyboard hook with password-gated re-injection, an HKLM bcrypt password store, a default-deny outbound allowlist firewall, a SHA-256-verified atomic self-updater, and a Windows Service supervisor. Absorbed the former Windows-Filter project.
JtechTools
The Discourse plugin bundle powering forums.jtechforums.org — production Ruby running in front of a real community of thousands. Ships dislike, SMTP, mini-mod, mod-categories and dumbcourse as one installable bundle behind six admin tabs.
Shul Widget
An Android home-screen widget that pulls live davening times from a shul's Luach feed. Written in Kotlin and distributed as a standalone app, in use at multiple synagogues already running Luach.
Open Source
Tools and plugins I build in the open — several running in production for the communities they serve.
JtechTools
A Discourse plugin bundle powering forums.jtechforums.org — dislikes, custom SMTP, a mini-moderation toolkit and moderator category controls, one install behind six admin tabs.
In production for a community of thousands
SK Music
A kosher filtered music client on Cloudflare Workers — a build-baked catalog, Hebrew-aware search that runs entirely in the browser, and an installable PWA. No search backend.
JTech Appstore
A curated app store for the JTech filtered-phone community — TypeScript over an IndexedDB-backed catalog, with an admin review queue and full-text search.
Otzar Hachochma Filter
Turns a Windows 11 Pro PC into a locked Otzar Hachochma kiosk: a passwordless standard user restricted to one app by NTFS execute-deny, a custom launcher bar, and printing preserved — while the admin account stays untouched.
SK-Tools
A privacy-first browser toolbox — PDF editor, video/audio/image converters, VCF splitter and a Claude chat — all running client-side, nothing uploaded.
Shul Widget
An Android home-screen widget that pulls live davening times from a shul's Luach feed. Built in Kotlin, in use at multiple synagogues.
Torah Anytime Downloader
A Windows desktop app that opens torahanytime.com through a local proxy and adds a one-click downloader — every lecture page gets a button that saves the shiur as a seekable MP4 or MP3 at your chosen resolution. Self-updating tray app that works behind TLS-intercepting filters.
SK Video Downloader
A Manifest V3 extension that detects videos on any page and downloads them as seekable MP4s — remuxing MPEG-TS and fragmented-MP4 HLS locally with a custom transmuxer, plus YouTube via player-stream capture. No servers, no WASM, no re-encoding.
kiosk-exit-guard
A single-executable Windows kiosk: a WebView2 window, a low-level keyboard hook with password-gated re-injection, a default-deny allowlist firewall and a SHA-256-verified self-updater.
Blog & Articles
I write about web development, design, and my journey building digital applications. Join me on this adventure!
Building SK Music: Hebrew-Aware Search That Runs in Your Browser
SK Music has no search server. The catalog is baked into the deploy and every query runs in a Web Worker on your machine — including the hard part: matching Hebrew titles against the romanized English a user actually types, by reducing both to a consonant skeleton.
Taking Software Apart: The Reverse Engineering I Actually Do
Reverse engineering isn’t one skill. It’s decompiling JARs, reading private APIs off the wire, deobfuscating rotating player JavaScript, and building things designed to resist all three — a field guide, with real examples from my own projects.
Windows Is Locked and Asking for a PIN: A Recovery Guide
Someone hands you a Windows 11 laptop that won't accept the password and is now demanding a PIN nobody knows. Here are the realistic recovery paths — from the easy fix to the bootable rescue toolkit you should already have on a USB stick.