# Doathingy
> Build the exact browser tool you need in plain English — no code, no downloads, no uploads. Your files never leave your device.

## What Doathingy does
Doathingy is an AI-powered browser-tool builder. Users describe what they need in plain English and receive a fully working, sandboxed browser tool within seconds. Every tool runs entirely client-side: files are processed in the browser, never uploaded to any server. Tools are saved permanently to the user's personal library and can be used as often as needed.

## Core facts
- Tools cost 1–3 credits to generate, depending on complexity
- Credits are priced at $0.25 each (cheaper in bundles and subscriptions)
- Privacy-first: all file processing happens locally; nothing is sent to a server
- No coding knowledge required; users describe the tool they need in plain English
- Every tool runs in a sandboxed iframe — safe, isolated, no third-party access
- Tools are saved permanently and can be rebuilt or tweaked at any time
- Users can share tools via a unique URL

## Technology
- Frontend: React 18, Vite, Firebase (Firestore + Auth)
- Tool generation: Gemini AI (Google)
- Tool runtime: Babel-transpiled JSX in a sandboxed iframe; React + CDN libraries loaded on demand
- Supported libraries: PDF processing (pdf-lib, pdfjs), image processing (fabric.js, pica, heic2any), video/audio (ffmpeg.wasm, wavesurfer.js), data tools (papaparse, xlsx, chartjs), and 30+ more

## Who it is for
- People who need to process files privately without uploading them to unknown servers
- Non-technical users who want custom automation without writing code
- Developers who need quick utility tools
- Anyone with repetitive file tasks: renaming, converting, merging, extracting, compressing

## Example tools users have built
- PDF text extractor
- Batch image resizer and converter
- Audio recorder with download
- Video trimmer (in-browser, no upload)
- CSV merger and cleaner
- QR code generator
- App Store screenshot generator
- Webcam photo booth
- Word count / reading time estimator
- Invoice PDF generator

## Doomsday Algorithm Trainer
A free interactive game for learning Conway's Doomsday Algorithm — the mental math method for calculating the day of the week for any date in history.
- Game (play): https://doathingy.com/doomsdaytrainer
- Guide (learn): https://doathingy.com/blog/doomsday-algorithm-trainer
- The Doomsday Algorithm was invented by John Horton Conway. It uses "doomsday" anchor dates (4/4, 6/6, 8/8, 10/10, 12/12; May 9, Sep 5, Jul 11, Nov 7; last day of February; Jan 3 or 4) that always fall on the same weekday within a year.
- Century anchors: 1800s = Friday, 1900s = Wednesday, 2000s = Tuesday, 2100s = Sunday.
- Year formula: a = YY÷12, b = YY mod 12, c = b÷4; doomsday = (a+b+c+anchor) mod 7.
- The trainer features timed practice, a heptagon layout, built-in reference databank, streak tracking, and a global leaderboard.

## Blog — free tool guides (238+ tool-specific landing pages)
Each blog post describes a specific pre-built tool: what it does, how to use it, and who it is for. All tools run entirely in the browser — no file uploads.

PDF tools:
- https://doathingy.com/blog/compress-pdf
- https://doathingy.com/blog/password-protect-pdf
- https://doathingy.com/blog/merge-pdf
- https://doathingy.com/blog/split-pdf
- https://doathingy.com/blog/pdf-to-text
- https://doathingy.com/blog/unlock-pdf
- https://doathingy.com/blog/rotate-pdf-pages
- https://doathingy.com/blog/add-page-numbers-to-pdf
- https://doathingy.com/blog/add-watermark-to-pdf
- https://doathingy.com/blog/fill-pdf-form
- https://doathingy.com/blog/delete-pdf-pages
- https://doathingy.com/blog/extract-pdf-pages
- https://doathingy.com/blog/scanned-pages-to-pdf

Image tools:
- https://doathingy.com/blog/compress-image
- https://doathingy.com/blog/remove-background
- https://doathingy.com/blog/bulk-image-converter
- https://doathingy.com/blog/image-resizer
- https://doathingy.com/blog/heic-to-jpg
- https://doathingy.com/blog/circle-crop-image
- https://doathingy.com/blog/grayscale-converter
- https://doathingy.com/blog/add-text-to-photos
- https://doathingy.com/blog/gif-to-jpg
- https://doathingy.com/blog/svg-to-jpgpng

Finance & calculators:
- https://doathingy.com/blog/savings-investment-calculator
- https://doathingy.com/blog/loan-calculator
- https://doathingy.com/blog/tip-calculator
- https://doathingy.com/blog/bmi-calculator
- https://doathingy.com/blog/percentage-calculator
- https://doathingy.com/blog/date-calculator
- https://doathingy.com/blog/unit-converter
- https://doathingy.com/blog/calorie-calculator
- https://doathingy.com/blog/salary-increase-calculator

Data & CSV tools:
- https://doathingy.com/blog/csv-to-json
- https://doathingy.com/blog/csv-merger
- https://doathingy.com/blog/csv-to-excel
- https://doathingy.com/blog/json-formatter
- https://doathingy.com/blog/xml-to-json-converter
- https://doathingy.com/blog/csv-viewer-editor
- https://doathingy.com/blog/csv-deduplicator

Security & encoding:
- https://doathingy.com/blog/aes-encrypt-decrypt
- https://doathingy.com/blog/password-protect-pdf
- https://doathingy.com/blog/hash-generator
- https://doathingy.com/blog/bcrypt-hasher
- https://doathingy.com/blog/rsa-key-pair-generator
- https://doathingy.com/blog/base64-encoderdecoder

Developer tools:
- https://doathingy.com/blog/css-gradient-generator
- https://doathingy.com/blog/qr-code-generator
- https://doathingy.com/blog/uuid-generator
- https://doathingy.com/blog/sql-formatter
- https://doathingy.com/blog/regex-tester
- https://doathingy.com/blog/cron-expression-builder
- https://doathingy.com/blog/color-contrast-checker
- https://doathingy.com/blog/utm-builder

(see /sitemap.xml for the complete list of all 238+ tool guides)

## URLs
- Homepage: https://doathingy.com/
- Live demos — try tools without signing in: https://doathingy.com/demo
- Blog — tool guides: https://doathingy.com/blog
- Sitemap: https://doathingy.com/sitemap.xml
- Privacy policy: https://doathingy.com/privacy
- Terms of use: https://doathingy.com/terms

## Pricing
- 10 free credits on sign-up
- Starter pack: $2.49 for 10 credits
- Value pack: $9.99 for 50 credits
- Subscription: $12.99/month for 200 credits/month
- Many tools are available free (no credits, no sign-in) via the /demo page

## Privacy
Doathingy does not collect, store, or process any user-uploaded file content. All processing happens inside the user's browser. The only data stored server-side is the tool code (the generated HTML/JS), user account info (email, credit balance), and tool metadata (name, description). No file content ever reaches Doathingy's servers.