# LocalPapa

> 53 free, privacy-first online tools that run 100% in the browser. Files never leave the device (no upload, no account, no install).

OKF knowledge pack: https://localpapa.com/okf/index.md

About this OKF bundle (how it is built & validated): https://localpapa.com/okf/about.md

Task guides (find a tool by goal): https://localpapa.com/okf/guides/index.md

Knowledge base — Zi Wei Dou Shu (Purple Star Astrology): https://localpapa.com/okf/ziwei/index.md

Knowledge base — Damo Yi Zhang Jing (the Palm Sutra): https://localpapa.com/okf/yizhang/index.md

Knowledge base — Western Astrology (sun signs): https://localpapa.com/okf/horoscope/index.md

Knowledge base — Tarot (78 cards): https://localpapa.com/okf/tarot/index.md

Knowledge base — Chinese Zodiac (生肖 & 合婚): https://localpapa.com/okf/zodiac/index.md

Knowledge base — Numerology (Life Path): https://localpapa.com/okf/numerology/index.md

Knowledge base — BaZi / Four Pillars (八字): https://localpapa.com/okf/bazi/index.md

Knowledge base — Name Numerology (五格剖象): https://localpapa.com/okf/name/index.md

Knowledge base — Blood Type Personality (血型性格): https://localpapa.com/okf/bloodtype/index.md

Machine-readable: https://localpapa.com/openapi.yaml · https://localpapa.com/ai-plugin.json · https://localpapa.com/sitemap.xml

## PDF Tools

- [Merge PDF Files](https://localpapa.com/tools/merge-pdf.html): Combine multiple PDFs into one — and pick specific pages per file
- [Split PDF / Remove Pages](https://localpapa.com/tools/split-pdf.html): Delete, extract, every N pages, or by ranges — five split modes
- [Rotate PDF Pages](https://localpapa.com/tools/rotate-pdf.html): Batch rotate upside-down scanned pages
- [Image to PDF](https://localpapa.com/tools/jpg-to-pdf.html): Convert JPG/PNG images to PDF — A4/Letter page, orientation, scaling and margins
- [PDF to JPG Images](https://localpapa.com/tools/pdf-to-jpg.html): Convert PDF pages to images — choose resolution, JPG/PNG/WebP format and page range
- [Unlock PDF](https://localpapa.com/tools/unlock-pdf.html): Remove password restrictions and protection from PDF
- [Add Watermark to PDF](https://localpapa.com/tools/pdf-watermark.html): Add text watermark: tiled anti-theft or 9-grid position, color, rotation, opacity and page range

## Multimedia & Audio

- [MP3 Audio Editor](https://localpapa.com/tools/mp3-editor.html): Trim, fade in/out, normalize, EQ, speed, and pick output bitrate
- [Online Tuner](https://localpapa.com/tools/tuner.html): Real-time mic pitch detection for guitar, ukulele and any instrument
- [Decibel / Noise Meter](https://localpapa.com/tools/decibel.html): Measure ambient sound level live — current, max, average & rating
- [Online Metronome](https://localpapa.com/tools/metronome.html): Rock-solid Web Audio scheduling — adjustable BPM, time signature, accent & tap tempo
- [Online Voice Changer](https://localpapa.com/tools/voice-changer.html): Real-time mic voice effects with presets, pitch control & recording
- [Convert MP4 to GIF](https://localpapa.com/tools/mp4-to-gif.html): Video to GIF — fps, size, aspect crop, boomerang and color control
- [Extract MP3 from Video](https://localpapa.com/tools/video-to-mp3.html): Convert MP4, MOV, WEBM to MP3 audio — no upload needed

## Image Tools

- [Image Compressor](https://localpapa.com/tools/compress-image.html): Reduce JPG / PNG / WebP file size while keeping visual quality
- [Image Resizer](https://localpapa.com/tools/resize-image.html): Resize by pixels or percentage — keep aspect ratio, batch support
- [Image Format Converter](https://localpapa.com/tools/convert-image.html): WebP ↔ JPG ↔ PNG — batch convert, no upload
- [Image Cropping Tool](https://localpapa.com/tools/crop-image.html): Drag and resize selection bounds locally
- [Remove Photo EXIF Metadata](https://localpapa.com/tools/remove-exif.html): Strip GPS, timestamps and device info — files never leave your browser
- [Color Eyedropper](https://localpapa.com/tools/color-tool.html): Color Eyedropper

## Developer Tools

- [Mermaid Online Editor](https://localpapa.com/tools/mermaid-editor.html): Live preview as you type — export PNG/SVG and generate a shareable link, data stays local
- [JSON Formatter / Validator](https://localpapa.com/tools/json-formatter.html): Format, minify, validate, escape — real-time error hints, data stays local
- [CSV Converter & Cleaner](https://localpapa.com/tools/csv-helper.html): CSV to JSON, clean empty lines, trim white spaces, data stays local
- [QR Code Generator](https://localpapa.com/tools/qr-generator.html): Generate QR codes for URLs, WiFi, text and more — no account needed
- [QR Code Scanner](https://localpapa.com/tools/qr-scanner.html): Scan live with your camera, or upload an image to decode QR / barcodes
- [Hash Generator](https://localpapa.com/tools/hash-generator.html): SHA-256 / SHA-1 / MD5 for text and files — everything stays local
- [Hardware Control Terminal](https://localpapa.com/tools/hardware.html): Web Bluetooth & Web Serial (USB) debugger
- [Mobile Sensor Dashboard](https://localpapa.com/tools/device-motion.html): Accelerometer · Gyroscope · Compass · Spirit Level · G-Force

## Games & Fun

- [Gomoku Game](https://localpapa.com/tools/gomoku.html): Connect five stones to win
- [2048 Game](https://localpapa.com/tools/game-2048.html): 2048 Game

## Engineering

- [DORI Calculator](https://localpapa.com/tools/dori-tool.html): DORI Calculator
- [Loan Calculator](https://localpapa.com/tools/loan-calculator.html): Loan Calculator
- [Online Calculator](https://localpapa.com/tools/calculator.html): Four-function arithmetic, keyboard input, automatic calculation history
- [Gimbal Motor Sizing Calculator](https://localpapa.com/tools/gimbal-motor-calculator.html): Derive motor torque/current from environment parameters and estimate a BaseCam drive architecture

## Fun & Interactive

- [Custom Decision Wheel](https://localpapa.com/tools/custom-wheel.html): Enter options and let fate decide
- [Lottery Lucky Numbers](https://localpapa.com/tools/lottery.html): Lucky numbers updated every 30 minutes
- [DCA Investment Calculator](https://localpapa.com/tools/stock-dca.html): Calculate compound growth with dollar-cost averaging and compare scenarios
- [Multi-Function Timer](https://localpapa.com/tools/timer.html): Countdown, Stopwatch & HIIT interval timer in one
- [Sports Tracker](https://localpapa.com/tools/sports-tracker.html): Pedometer, GPS speedometer & route logger in one — location stays private
- [Inclinometer / Level](https://localpapa.com/tools/inclinometer.html): Measure tilt angle, grade % and level with your phone sensors — with zero calibration
- [Zi Wei Dou Shu (Purple Star) Chart](https://localpapa.com/tools/ziwei.html): Enter a Gregorian birth date and hour to instantly cast the chart — 12 palaces, Four Transformations and decade luck
- [Damo Yi Zhang Jing (Palm Sutra) Reading](https://localpapa.com/tools/yizhang.html): Enter a Gregorian birth date and hour to place the four pillars onto the twelve palm stars
- [Western Zodiac Sign Finder](https://localpapa.com/tools/horoscope.html): Enter a birth date to find your sun sign, element, personality and compatibility
- [Online Tarot Reading](https://localpapa.com/tools/tarot.html): Hold a question in mind, shuffle and draw for upright / reversed meanings
- [Chinese Zodiac & Marriage Compatibility](https://localpapa.com/tools/zodiac.html): Find your zodiac animal, element and personality, and check 合婚 compatibility
- [Numerology Life Path Calculator](https://localpapa.com/tools/numerology.html): Enter a birth date to get your Life Path & Birthday numbers, character, gifts and challenges
- [BaZi · Four Pillars Chart](https://localpapa.com/tools/bazi.html): Enter a Gregorian date and hour to cast the eight characters, Day Master, Ten Gods and five elements
- [Chinese Name Numerology · Five Grids](https://localpapa.com/tools/name.html): Enter a Chinese name to get the five grids, Three Talents and the 81 numbers

## Experimental

- [Word Battlefield](https://localpapa.com/tools/word-war.html): Draw character tiles, drag to deploy, merge Three-Kingdoms hero names — hanzi tower defense
- [Falling Notes Piano](https://localpapa.com/tools/midi-piano.html): Upload a MIDI; notes fall to show which key to play. Remap keys freely, learn with wait mode.
- [Taiwan Air Quality (AQI) — Live](https://localpapa.com/tools/air-quality.html): Real-time AQI, PM2.5, PM10 and ozone from all Taiwan stations — filter by county or find the nearest station
- [PDF to Markdown](https://localpapa.com/tools/pdf-to-markdown.html): Extract text content from PDF as Markdown format
- [Digital Magnifier](https://localpapa.com/tools/magnifier.html): Magnify small text & details live with your camera — freeze, light & snapshot