I'm a full-stack and AI engineer who treats programming languages the way most engineers treat libraries โ a temporary obstacle, never a project limit. I work for small clients and niche communities where one engineer covers the whole stack, so I've shipped production code in JavaScript, TypeScript, Go, Ruby, Python, Kotlin, C, HTML, CSS, and SQL โ and I pick up whatever the next project actually needs.
- ๐ป Web โ Modern JavaScript (ES6+), Tailwind, Alpine.js, and Vite on the front; Supabase (PostgreSQL with thorough RLS, Edge Functions, Auth, Realtime) on the back. Deployed to Cloudflare Pages & Workers.
- โ๏ธ Systems โ Go and C for Windows tooling: kiosk lockdowns with low-level keyboard hooks, default-deny WFP firewalls, kernel-mode drivers, single-binary services with SHA-256-verified self-updaters.
- ๐ค AI Engineering โ Claude-powered features inside client portals, Gemini-backed automations, and prompt-and-retrieval pipelines that turn a four-hour manual workflow into a one-click button. I integrate the model, ship the UI, and stand behind the backend that keeps it billable.
- ๐งฉ Client-Side & WASM โ When a workflow is better off never touching a server, I lean on
ffmpeg.wasm,pdf-lib, andPDF.jsto deliver desktop-class tooling that runs entirely in the browser. - ๐ฌ Reverse Engineering โ APK/DEX and smali, ADB over WebUSB, system partitions, and private APIs read off the wire โ then rebuilding things designed to resist all three.
Outside of client work I'm a moderator on JTech Forums, a Jewish tech community focused on filtered phones, MDMs, and kosher device tooling. Triaging filter-bypass discussions and keeping a busy forum signal-rich has been a useful forcing function for thinking about community design and content policy โ and it's where most of my GroupMe and Google Apps Script tutorials started.
Whether the answer is a Ruby Discourse plugin, a Go Windows binary, a Supabase real-time UI, or a Claude-powered admin tool, the goal is the same: software that quietly works for the people who depend on it, long after I've moved on.
๐ Cleveland, OH ยท ๐ผ Available for freelance work ยท โ๏ธ shalomkarr@gmail.com
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| Frontend |
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| Backend & Platform |
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| AI & Data |
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| Systems & Reverse Eng. |
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| Client-Side & WASM |
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| Tooling & Ecosystem |
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A fast, kosher, filtered YouTube music client โ search and stream a whitelisted catalog, filtered by construction.
Most music apps solve filtering with a blocklist and hope. SK Music inverts it โ every song comes from a pre-approved artist, so the catalog is accurate by construction rather than by moderation. The interesting part is what that let me delete.
- ๐ No search backend. The catalog is compressed and baked into the deploy at build time. Every query runs in a Web Worker on your machine โ there is no search API to call, rate-limit, or pay for.
- ๐ค Hebrew-aware fuzzy matching. The hard problem is that users type romanized English for titles stored in Hebrew. Both sides get reduced to a consonant skeleton, so "Mimkomcha" finds ืืืงืืื regardless of which vowels anyone guessed.
- โก Static-first.
dist/holds the entire SPA, search engine, baked catalog and assets on Cloudflare Workers Static Assets. The Worker itself stays thin โ live playlists, trending, and anonymous analytics only. - ๐ด Installable PWA with service-worker caching, backed by Supabase for analytics and parental controls.
โถ๏ธ Plays through the official YouTube IFrame Player API โ nothing is hosted or re-encoded. Catalog originates from the Zemer project by @alltechdev. GPL-3.0, non-commercial, shipped by GitHub Actions on push tomain.
| Project | Description | Tech Stack |
|---|---|---|
| ๐ก๏ธ lockguard | Kernel-mode Windows 11 lockdown. A BootStart driver enforces a WFP network filter, registry/process/file/object callbacks, and a WDAC allowlist; recovery is gated behind PBKDF2 at a million iterations. Written to resist a tech-savvy administrator, not merely inconvenience one. | C (WDK), Go, Win32 |
| ๐ kiosk-exit-guard | A 7.9 MB single executable that turns a Windows machine into a locked kiosk โ WebView2 window, low-level keyboard hook with password-gated re-injection, HKLM bcrypt password store, default-deny outbound firewall, SHA-256-verified atomic self-updater, and a Service supervisor. | Go, Win32, WebView2 |
| ๐ JtechTools | The Discourse plugin bundle powering forums.jtechforums.org โ production Ruby in front of a real community of thousands. Ships dislikes, custom SMTP, mini-mod, mod-categories and dumbcourse as one install behind six admin tabs. | Ruby, Discourse, Ember.js |
| ๐งฐ SK Tools | A privacy-first browser toolbox โ PDF editor, video/audio/image converters, VCF splitter, and a BYO-key Claude chat. Every byte is processed client-side; nothing is ever uploaded. | WebAssembly, ffmpeg.wasm, pdf-lib |
| ๐ RevealOS Unfilter | A hardware-interfacing web utility that modifies system-level partitions on restricted Android devices straight from the browser over WebUSB and ADB โ restoring functionality without compromising device integrity. | WebUSB, ADB, Vanilla JS |
| โฌ๏ธ SK Video Downloader | A Manifest V3 extension that detects videos on any page and saves them as seekable MP4s โ remuxing MPEG-TS and fragmented-MP4 HLS locally with a custom transmuxer. No servers, no WASM, no re-encoding. | JavaScript, MV3, HLS |
| ๐ CMH Luach | Multi-tenant halachic display boards for Orthodox shuls โ per-tenant Supabase table prefixes, KosherZmanim, Open-Meteo weather, and an offline-capable service worker. Multiple live shul tenants on one codebase. | Supabase, KosherZmanim, Service Workers |
| ๐ฏ๏ธ Khal Yereim | Full synagogue platform โ halachic zmanim with a "Next Minyan" countdown, digital mikvah passes, Zelle donations, bilingual Hebrew/English, and a custom WYSIWYG print engine. | Vanilla JS, Cloudflare Workers, KosherZmanim |
| ๐๏ธ Baltimore Community Resource Network | Plain-language guides to SNAP, Medicaid and WIC, where admins edit every page through a side-by-side markdown editor with live preview and image upload. No build step, fully content-editable. | Vanilla JS, Supabase |
| ๐ฑ SK News Network | Real-time news platform for the Yeshiva community โ Supabase live feed, SMS alert subscriptions, community Chats + Sites directories, and dual admin CMS panels. | Supabase, Tailwind, Vanilla JS |
| ๐ Shul Widget | An Android home-screen widget pulling live davening times from a shul's Luach feed, so the day's zmanim sit on the home screen without opening an app. In use at multiple synagogues. | Kotlin, Android |
๐ข Client Platforms & Community Sites โ click to expand
| Project | Description | Tech Stack |
|---|---|---|
| ๐ฝ๏ธ Dinner Done | End-to-end e-commerce for high-volume catering โ guest checkout, live inventory, invoice processing, and a custom admin dashboard that updates site content dynamically. | Supabase, JS, Apps Script |
| ๐ฟ Torah Life Kollel | Beis medrash and kollel platform โ dynamic davening schedule, shiurim listings, and a tax-deductible donation portal across three sedarim. | Vanilla JS, KosherZmanim |
| ๐ฉบ On Target ABA | Evidence-based ABA therapy and autism evaluation services, built around a low BCBA-to-client ratio and insurance intake. | Vanilla JS, Static HTML/CSS |
| ๐ New Bridges ABA | Serverless intake platform for a multi-state ABA provider โ soft-UI design system with custom patient-onboarding analytics. | Tailwind, Alpine.js, Supabase |
| ๐งฉ Every Child ABA | Zero-framework SPA for an in-home autism therapy clinic, tuned for local SEO with Schema.org JSON-LD. | Vanilla JS, Schema.org |
| ๐ฐ The Hock Cleveland | Hyper-local community media โ weekly email digest plus a real-time WhatsApp flash-alert channel. | Vanilla JS, Supabase |
| ๐ Telshe Yeshiva | Site for the Rabbinical College of Telshe โ a premier Makom Torah dedicated to Amalas Hatorah and Hashkafa. | Vanilla JS, Static HTML/CSS |
| ๐งบ SpinCycle Rentals | Marketing and booking site for an all-in-one washer/dryer rental service in Cleveland. | Vanilla JS, Supabase |
| ๐ก AddressIt LED | Marketing site for illuminated house-number signs by Illumicor โ when seconds count, be seen. | HTML5, CSS, JS |
| ๐จ YS Handymen | Lead-gen site for a Cleveland handyman service โ small jobs, big difference. | HTML5, CSS, JS |
| โ๏ธ Visual PDF Editor | 100% client-side PDF editor โ merge, reorder, redact, stamp, sign, and encrypt, all in the browser. | pdf-lib, PDF.js, PWA |
| ๐ฎ SK Games | Classic browser games โ chess with a minimax bot, checkers, connect four, unbeatable tic-tac-toe, wolf & sheep, memory match. No installs, no ads. | Vanilla JS, Tailwind |
Tools and plugins I build in the open โ several running in production for the communities they serve.
| Repo | What It Is | Language | Stars |
|---|---|---|---|
| JtechTools | Discourse plugin bundle powering forums.jtechforums.org โ dislikes, custom SMTP, a mini-moderation toolkit and moderator category controls, one install behind six admin tabs. | Ruby |
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| SK-Music | Kosher filtered music client on Cloudflare Workers โ build-baked catalog, Hebrew-aware search that runs entirely in the browser, installable PWA. | JavaScript |
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| JTech-Appstore | Curated app store for the JTech filtered-phone community โ TypeScript over an IndexedDB catalog, with an admin review queue and full-text search. | TypeScript |
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| SK-Tools | Privacy-first browser toolbox โ PDF editor, video/audio/image converters, VCF splitter and a Claude chat, all running client-side. | JavaScript |
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| Shul-Widget | Android home-screen widget pulling live davening times from a shul's Luach feed. In use at multiple synagogues. | Kotlin |
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| AI-Number-Blocklist | Community blocklist of 15,000+ AI robocaller numbers in E.164 โ importable into call-blocking apps, PBX systems and kosher filtering services. | Data |
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| kiosk-exit-guard | Single-executable Windows kiosk โ WebView2 window, password-gated keyboard hook, default-deny allowlist firewall, SHA-256-verified self-updater. | Go |
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| otzar-hachochma-filter | Turns a Windows 11 Pro PC into a locked Otzar Hachochma kiosk via NTFS execute-deny, with printing preserved and the admin account untouched. | PowerShell |
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| lockguard | Kernel-mode Windows 11 lockdown โ WFP firewall at the driver layer plus registry, process and file callbacks. Driver in C, watchdog in Go. | C |
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| SK-Video-Downloader | MV3 extension that remuxes HLS locally with a custom transmuxer to produce seekable MP4s. No servers, no re-encoding. | JavaScript |
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| Torah-Anytime-Downloader | Desktop app + local proxy for TorahAnytime with a built-in seekable lecture downloader (MP4/MP3). Works behind TLS-intercepting filters. | JavaScript |
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I write about the things I actually build โ search algorithms, reverse engineering, and Windows internals.
- Building SK Music: Hebrew-Aware Search That Runs in Your Browser โ SK Music has no search server. The catalog is baked into the deploy and every query runs in a Web Worker, including the hard part: matching Hebrew titles against the romanized English a user actually types.
- Taking Software Apart: The Reverse Engineering I Actually Do โ Decompiling JARs, reading private APIs off the wire, deobfuscating rotating player JavaScript, and building things designed to resist all three.
- Windows Is Locked and Asking for a PIN: A Recovery Guide โ The realistic recovery paths, from the easy fix to the bootable rescue toolkit you should already have on a USB stick.
"I genuinely thrive on the analytical challenges inherent in software development. Driven by a love for problem-solving and innovation, I strive not just to meet user needs but to anticipate them."
