A privacy-first collection of developer utilities that run in your browser. Tool inputs — from JSON and secrets to PDFs and images — are processed locally with no backend, accounts, uploads, or ads. The official hosted app collects basic page-usage telemetry; it never includes tool inputs.
🔗 Live app: https://techtocore.github.io/Dev-Toolbox/ 📲 Installable: it's a PWA — install it to your home screen or desktop. Local tools work offline after the app is cached; network-dependent model downloads and public-IP lookup are clearly opt-in.
- Local AI (Chat) — A small language model that runs fully on-device via WebGPU. No accounts, no servers — your conversation never leaves the browser. Hardware-aware model picker spanning Qwen (Alibaba), Gemma (Google), Llama (Meta), and Phi (Microsoft) — from a ~0.4 GB tiny model for phones up to larger models for capable GPUs — with one-time cached downloads and tunable generation settings.
- Token Counter & Cost Estimator — Estimate token counts and API costs across LLM providers.
- Prompt Optimizer — Score a prompt against best practices, then rewrite it with the on-device AI.
- Prompt Template Builder — Reusable prompt templates with variables.
- JSON Schema Generator — Build JSON schemas for structured LLM output, or describe your data and let the on-device AI draft the fields.
On-device AI Assist is also embedded as an optional, private co-pilot inside several tools (collapsed by default, degrades gracefully without WebGPU): Prompt Optimizer, Regex Tester (English → pattern), SQL Query Builder (English → SQL), JSON Schema Generator, and Data Profiler. The model loads once and is shared across every tool.
- JSON Formatter — Validate and pretty-print JSON with a collapsible tree view.
- JSON to TypeScript — Generate TypeScript interfaces (or type aliases) from a JSON sample; nested objects and arrays of objects are merged into clean, optional-aware types.
- Timestamp Converter — Convert between Unix timestamps, ISO 8601, and human-readable formats.
- Base64 Encode/Decode — Convert text to/from Base64.
- Hash Generator — MD5, SHA-1, SHA-256, SHA-512 (and keyed HMAC).
- JWT Decoder — Decode and inspect JWT header, payload, and signature.
- URL Encode/Decode — Encode/decode URL components and strings.
- Certificate Information — Extract and view X.509 certificate details.
- Password & Passphrase Generator — Cryptographically-strong passwords and memorable passphrases via the Web Crypto CSPRNG, with a live entropy/strength estimate. Never transmitted.
- CSV/JSON Converter — Convert between CSV/TSV and JSON (RFC-4180 quote-aware parsing).
- Data Profiler — Data-quality stats and patterns, with optional on-device AI insights.
- SQL Query Builder — Build queries visually, or describe them in plain English with on-device AI.
- Numeric Summary — Statistical analysis of numeric data (mean, median, mode, …).
- Diff Checker — Side-by-side difference highlighting.
- Markdown Editor — Live markdown preview and editing.
- Word Counter — Words, characters, lines, and more.
- Case Converter — Convert between
camelCase,snake_case,kebab-case,CONSTANT_CASE,Title Case, slugs and more — identifier styles re-tokenize, prose styles keep your layout.
- Regex Tester — Live matching/highlighting, or generate a pattern from plain English (on-device AI).
- UUID Generator — Generate UUIDs (v4 and more) in bulk.
- Number Base Converter — Convert integers between binary, octal, decimal, hex and any base from 2–36;
BigInt-backed so huge values stay exact. - Cron Expression Helper — Explain a 5-field cron schedule (and
@daily/@hourlynicknames) in plain English, expand each field, and preview the next run times. - Color Converter — HEX ⇄ RGB ⇄ HSL ⇄ HSV ⇄ CMYK with a picker and a WCAG contrast check.
- IP & Browser Info — Your public IP, ISP, location, timezone, and browser/device details.
- QR Code Generator — QR codes from text, URLs, or Wi-Fi credentials; download as PNG or SVG.
- Bubble Level — A spirit level driven by your device's motion sensor, with calibration and haptics.
- Compass — A magnetic compass with a live rotating rose.
- Sound Level Meter — Live microphone loudness meter with peak/average stats (works on desktop too).
- Merge PDF — Combine multiple PDFs into one.
- Split / Extract PDF — Pull a page range into a new file.
- Organize PDF — Reorder, rotate, and delete pages.
- Images to PDF — Combine images into a PDF (A4 / Letter / fit-to-image).
- Image Resizer & Compressor — Resize, compress, and convert (PNG / JPEG / WebP) with before/after sizes.
- Image Metadata Viewer & Stripper — Inspect EXIF/GPS metadata and download a stripped, share-safe copy.
- Image to Base64 Data URI — Convert an image to a data URI (with CSS/HTML snippets) and back.
Tool inputs are processed entirely in the browser — files, text, keys, images, and AI prompts are never uploaded to an application server. The official GitHub Pages deployment uses Google Analytics for basic page-view telemetry with Google Signals and ad-personalization signals disabled. Local and self-hosted copies do not load it.
Two features make explicit network requests: Local AI downloads model weights from the model host before inference runs on-device, and IP & Browser Info contacts a public IP service only after consent. Those tools explain the request before it happens; the rest of the toolbox works locally and can be used offline once the PWA assets are cached.
- Node.js
^22.22.3 || ^24.15.0 || >=26(required by Angular 22 — Node 24 LTS recommended) and a recent npm. - For Local AI: a WebGPU-capable browser (recent Chrome/Edge on desktop, or Safari 18+).
git clone https://github.com/techtocore/Dev-Toolbox.git
cd Dev-Toolbox
npm installnpm startNavigate to http://localhost:4200/. The app reloads automatically on source changes.
npm run buildArtifacts are emitted to dist/dev-toolbox/. Production builds include the service worker (ngsw-worker.js) and web manifest, so the deployed app is installable and offline-capable.
npm run lint # ESLint (flat config)
npm run typecheck # application and test TypeScript checks
npm run test:ci # unit tests (Karma + Jasmine, headless Chrome)
npm run check # lint + typecheck + tests + production audit + buildTesting the PWA locally: service workers require a production build served over HTTP(S), not
ng serve. Build, then servedist/dev-toolbox/browser/with any static server (e.g.npx http-server dist/dev-toolbox/browser).
- Angular 22.2 — standalone-free NgModule app using the modern control-flow syntax (
@if,@for). - TypeScript 6.0 — type-safe development (pinned
<6.1to match Angular 22's build toolchain). - Angular Service Worker — installable, offline-capable PWA.
- Bootstrap 5.3 + Bootstrap Icons — responsive UI.
- RxJS 7.8 · Zone.js 0.16.
- ESLint 10 — flat config (
eslint.config.js) withangular-eslint+typescript-eslint. - @mlc-ai/web-llm 0.2 — in-browser LLM inference over WebGPU (Web Worker backed, lazy-loaded).
- pdf-lib, qrcode, exifr — PDF/QR/EXIF tooling, dynamically imported so they stay in lazy chunks.
- marked 18 (Markdown), node-forge 1.4 (X.509), crypto-js 4.2 (hashing/HMAC).
This project is open source and available for use and modification.