Web Tools

A Cloudflare Worker that serves a suite of browser-based developer and utility tools. Most pages run entirely in the browser; account-backed features use Cloudflare D1 plus Google OAuth.

Tools

• Markdown Viewer (/markdown)

  • GitHub-flavored Markdown via marked, sanitized with DOMPurify, and rendered with MathJax.
  • Syntax highlighting via Highlight.js with light/dark theme swapping.
  • Multi-document tabs stored locally or synced to D1 for signed-in users via /api/pages/*.
  • Copy rendered HTML to the clipboard.

• Euler Preview (/euler)

  • Preview Project Euler forum posts with BBCode, TeX, and Highlight.js code blocks.
  • Supports forum-style tags such as headings, quote/list/collapse blocks, alignment, and [code=lang].
  • Multi-document tabs stored locally or synced to D1 for signed-in users via /api/pages/*.
  • Copy rendered HTML to the clipboard.

• Pastebin (/pastebin)

  • Create snippets with public, unlisted, or private visibility.
  • Public feed plus a signed-in per-user list; direct links open at /pastebin/p/:id.
  • Guest mode stores drafts in localStorage when you are not signed in.

• Text Diff (/diff)

  • Compare original and changed text line by line with git-style output.
  • Shows added, removed, changed, and unchanged counts.
  • Includes swap, clear, large-input warnings, and localStorage persistence.

• Base64 Encoder/Decoder (/base64)

  • Encode files to raw Base64 and data URLs via drag and drop or a file picker.
  • Decode raw Base64 or data URLs back into downloadable files with configurable filename and MIME type.
  • Includes UTF-8 text encode/decode helpers and clipboard copy actions.

• Image Editor (/image-editor)

  • Load images from file picker, drag and drop, or clipboard paste.
  • Zoom, pan, rotate in 90 degree steps, crop interactively, and reset edits.
  • Export PNG, JPG, or WEBP with quality controls where applicable, then download or copy the edited image.

• URL Encode/Decode (/url-encode-decode)

  • Encode and decode URL components in the browser.
  • Move output back into input for multi-level transforms.
  • Includes swap, clear, and clipboard copy helpers.

• Data Format Converter (/format-tools)

  • Convert between JSON, YAML, TOML, and CSV.
  • Validate parsed output against JSON Schema with Ajv 2020.
  • Compare source and converted content with text or semantic diff views.
  • Persists the last inputs and settings in localStorage.

• CSV Viewer & Editor (/csv-editor)

  • Import CSV with or without header rows into an Excel-like grid.
  • Add/delete rows and columns, sort/filter columns, and copy selected cells.
  • Export CSV with comma, semicolon, or tab delimiters, or copy TSV for Sheets/Excel.
  • Persists the grid in localStorage and warns on large datasets.

• To-Do List (/todo)

  • Signed-in, D1-backed task manager with priorities, categories, due dates, and descriptions.
  • Stats cards plus filters for status, priority, and category.
  • Supports create, edit, toggle, delete, and cross-device sync.

• Daily Goal Tracker (/goals)

  • Signed-in, D1-backed goal tracker with one card per goal and a current-month calendar.
  • Each day cycles through complete, partial, missed, or empty state.
  • Designed for quick daily habit tracking with immediate sync.

• Date Calculator (/date)

  • Compute date differences in days, weeks, and calendar year/month/day terms.
  • Add or subtract days, weeks, months, or years from a base date.
  • Includes a custom date picker plus "Set to Today" shortcuts.

• LLM Cost Calculator (/llm-cost)

  • Parse token usage dumps, including cached and reasoning tokens.
  • Price input, cached input, output, and reasoning tokens per token, per 1K, or per 1M.
  • Save model pricing profiles locally and copy a cost summary.

• Actuary Calculator (/actuary)

  • XKCD-style group mortality odds using Social Security actuarial tables.
  • Accepts multiple ages with optional gender suffixes and an optional horizon.
  • Reports 5/50/95% timing plus horizon probabilities.

• YouTube Transcript (/yt-transcript)

  • Fetch transcripts for public YouTube videos, with optional translation when available.
  • Accepts full URLs, short URLs, or bare video IDs.
  • Shows normalized segments plus full transcript text with copy support.

• TIFF Viewer (/tiff-viewer)

  • Decode TIFF images locally from file input or pasted Base64/data URLs using bundled UTIF.js.
  • Toggle, solo, and recolor channels for multi-channel images.
  • Zoom in/out, fit to width, and inspect large images without server-side processing.

All tools use the shared header/theme assets in public/shared, and the home page at / provides searchable tiles for the full suite.

Routes

Tool pages

• / - searchable tools index.
• /markdown - Markdown Viewer.
• /euler - Euler Preview.
• /pastebin - Pastebin UI.
• /diff - Text Diff.
• /base64 - Base64 Encoder/Decoder.
• /image-editor - Image Editor.
• /url-encode-decode - URL Encode/Decode.
• /format-tools - Data Format Converter.
• /csv-editor - CSV Viewer & Editor.
• /todo - To-Do List.
• /goals - Daily Goal Tracker.
• /date - Date Calculator.
• /llm-cost - LLM Cost Calculator.
• /actuary - Actuary Calculator.
• /yt-transcript - YouTube Transcript.
• /tiff-viewer - TIFF Viewer.

Data and auth routes

• /pastebin/p/:id - view a specific paste.
• /api/auth/me - current session status.
• /api/auth/logout - log out the current session.
• /auth/google/login - start Google OAuth.
• /auth/google/callback - Google OAuth callback.
• /api/pastebin/create, /api/pastebin/mine, /api/pastebin/public, /api/pastebin/get, /api/pastebin/delete
• /api/pages/create, /api/pages/list, /api/pages/get, /api/pages/update, /api/pages/delete
• /api/todo/create, /api/todo/list, /api/todo/get, /api/todo/update, /api/todo/toggle, /api/todo/delete
• /api/goals/create, /api/goals/list, /api/goals/delete, /api/goals/entry
• /api/yt-transcript
• /api/_internal/seed - internal test helper.

Project Structure

• src/index.ts - Worker entry; dispatches auth, API, dynamic paste, and static tool routes.
• src/static.ts - pretty-route mapping for all HTML tool pages in public/.
• src/auth.ts - Google OAuth, session lookup, and logout handling.
• src/pastebin.ts - Pastebin API and /pastebin/p/:id page handling.
• src/pages.ts - D1-backed saved pages for Markdown Viewer and Euler Preview.
• src/todo.ts - To-Do List API.
• src/goals.ts - Daily Goal Tracker API.
• src/routes/transcript.ts and src/yt-transcript.ts - YouTube transcript endpoint and fetch logic.
• public/ - one HTML page per tool, plus public/shared/ for shared UI assets.
• public/vendor/utif.js - bundled TIFF decoder used by the viewer.
• migrations/0001_pastebin.sql through migrations/0006_tool_pages.sql - D1 schema for users/sessions, pastebin, todos, goals, and synced editor pages.
• test/index.spec.ts - worker tests with Vitest and the Cloudflare Workers pool.
• wrangler.jsonc - Wrangler config and bindings.

Development

• Install dependencies: npm install
• Start local dev server: npm run dev or npm start
• Run tests: npm test
• Deploy: npm run deploy
• Refresh generated Cloudflare types after binding changes: npm run cf-typegen

If you change only static HTML in public/, you usually do not need Worker code changes unless the route surface or backing APIs change.

Account-Backed Features Setup

The following features require D1 and Google OAuth:

• Pastebin account storage and private/unlisted sharing
• Markdown Viewer and Euler Preview synced pages
• To-Do List
• Daily Goal Tracker

Everything else works without D1 or OAuth.

1. Create a D1 database and bind it in wrangler.jsonc.
2. Apply the migrations:
   • wrangler d1 migrations apply web_tools_db
   • Replace web_tools_db with your actual database binding name if needed.
3. Configure Google OAuth:
   • Create an OAuth 2.0 Web application in Google Cloud Console.
   • Add an authorized redirect URI: https://YOUR_DOMAIN/auth/google/callback
   • Set GOOGLE_CLIENT_ID and OAUTH_REDIRECT_URL in wrangler.jsonc vars.
   • Set the client secret with wrangler secret put GOOGLE_CLIENT_SECRET.
   • Optionally set SESSION_COOKIE_NAME (defaults to wt_session).
4. For local development, make sure the dev callback URL matches your configured redirect URI. Using HTTPS locally or a tunnel is usually easiest for OAuth testing.

Security notes:

• Sessions use random tokens stored in D1 and are set as HttpOnly, Secure, SameSite=Lax cookies.
• Only public pastes appear in the public listing.
• unlisted and private pastes do not appear in public listings; private pastes are owner-only.
• Guest paste mode uses localStorage, so those drafts stay on the same browser/device.

Notes

• MathJax inline delimiters are restricted to $...$ to avoid conflicts with ordinary text. Display math supports $$...$$ and \[...\].
• Rendered HTML is sanitized before insertion. Be careful if you change the sanitization path.

License

MIT - see LICENSE.md.