SpecimenCase No. 02 · Selected work

Tamasvi Tools — 68 Local-First Utilities

Sixty-eight free, local-first utilities — photo editing, compressors, converters, SQL on files, PDF & ZIP tools, calculators, and more. Everything runs in your browser; nothing is ever uploaded.

Next JSTypeScriptWebAssemblyDuckDB-WASMBrowser APIs
Browse all toolstamasvi.com
68Tools
8Trays
100%Client-side
$0Forever

Overview

68 Local-First Utilities

Tamasvi Tools is a drawer of 68 single-purpose utilities built on modern browser APIs — WebAssembly, the File System Access API, hardware-accelerated codecs, and Web Crypto. Each tool opens instantly, needs no account, and processes your files entirely on your machine.

Toolbox

Sixty-eight tools, eight trays

Tray I

Photo

7 tools
Image CropperDrag handles to crop. Aspect-ratio presets (1:1, 4:3, 16:9, free), circle mode for avatars.Image ResizerResize images by dimensions or percentage. Lock aspect ratio, batch resize, instant download.Rotate & FlipRotate photos 90°, 180°, 270°, or any custom angle. Flip horizontal or vertical.Photo FiltersAdjust brightness, contrast, saturation, hue. Apply sepia, grayscale, and preset looks.WatermarkAdd text watermarks with custom position, opacity, color, and tiling. Protect your photos.Background RemoverRemove backgrounds with magic wand or chromakey. Tune tolerance, export with transparency.Batch EXIF ScrubberInstantly strip all camera and GPS metadata from 100+ photos at once client-side in milliseconds.
Tray III

Convert

17 tools
CSV → JSONDrop a CSV, get clean JSON. Header detection, type guessing, live preview.JSON → CodeConvert JSON to TypeScript, Go, Python, Rust, and more instantly.JSON → CSVFlatten JSON to CSV with smart key paths, array expansion, and live preview.Image ConverterConvert images between PNG, JPG, WebP, and BMP. Batch supported, quality slider, instant download.Image → PDFCombine JPG, PNG, or WebP images into a single PDF. Reorder pages, pick page size, fit to page.SVG → PNGRasterize SVG to PNG, JPG, or WebP at any width. Transparent or solid background.Text → ImageTurn styled text or raw SVG into a crisp PNG, JPG, or SVG. Font, color, background, and up to 3× export.JSON ↔ YAMLConvert between JSON and YAML with live preview, type inference, and instant copy.JSON ↔ XMLConvert between JSON and XML. Pretty output, attribute support, choose root element.Markdown ↔ HTMLRender markdown to clean HTML or convert HTML back to markdown. Side-by-side preview.Text EncoderURL, HTML, Base64, Hex, Binary, Morse, ROT13, case conversions — one tool, many codecs.JWT DecoderInspect JSON Web Token header, payload, claims, and expiry. Token stays local.Hash GeneratorGenerate MD5, SHA-1, SHA-256, and bcrypt hashes locally. Verify file integrity or secure strings.Epoch ConverterConvert between Unix timestamps and human-readable dates. Auto-detects seconds and milliseconds.Cron Expression ParserTranslate complex cron schedules into human-readable English and calculate upcoming execution dates.Base64 Encoder / DecoderDrag & drop any file or image to get its Base64 string, or paste Base64 to decode it back to a file. Runs entirely in your browser.HEIC → JPG ConverterConvert iPhone HEIC/HEIF photos to JPG or PNG locally. Batch supported, quality slider, no upload ever.
Tray V

Data

11 tools
Text Diff CheckerCompare two text or code snippets to see local differences. Side-by-side or inline view.Password / UUID GeneratorGenerate secure, random passwords and UUIDs locally using native cryptographic APIs.Regex TesterTest regular expressions securely against strings using native APIs. No data leaves your browser.JSON Schema ValidatorValidate complex JSON payloads against strict schemas securely in your browser.Chmod CalculatorVisually calculate Unix file permissions and instantly get octal, symbolic, and terminal commands.Real-time Log AnalyzerGrant a log directory and stream every file into a live Kibana-style dashboard. Filter by level, search, watch event rates in real time.Word / Character CounterReal-time word, character, line, sentence, and paragraph counts with reading and speaking time estimates.PDF Merge & SplitCombine multiple PDFs into one or split a PDF into custom page ranges. Local — files never leave your browser.ZIP Creator & ExtractorBundle files and folders into a ZIP, or open any archive to browse the tree and pull out individual files or sub-folders.Bulk File RenamerGrant access to a messy folder, set a regex rule or sort by EXIF date, and rename or move files in place. No upload, no zipping.Duplicate File FinderPoint it at a massive folder. Streams every file through a chunked SHA-256 hasher, groups identical copies, and lets you delete duplicates straight off your disk.
Tray VII

Web

6 tools
Color Palette ExtractorDrop an image, get its dominant colors with hex, RGB, HSL, and copy-ready CSS.Font DetectorDetect every font declared on a webpage. Follows linked stylesheets, groups by family, identifies the provider.SEO SnapshotAudit any URL: title, description, canonical, OG, Twitter cards, JSON-LD, hreflang — with green/amber/red checks.QR Code GeneratorGenerate beautiful vector QR codes or scan uploaded QR images instantly.URL Parser & BuilderBreak down complex URLs into their components and safely edit query parameters without breaking encoding.Color Contrast CheckerCheck foreground/background color pairs against WCAG 2.1 AA and AAA accessibility standards instantly.
Tray VIII

Calculators

17 tools
Scientific CalculatorTrig, log, factorial, memory, history. RAD/DEG modes.Base ConverterBinary, octal, decimal, hex — convert across radixes.Bitwise CalculatorAND, OR, XOR, NOT, shifts on 32-bit integers.Color ConverterHEX ↔ RGB ↔ HSL with live swatch.Timestamp ConverterUnix epoch ↔ ISO datetime, with timezone.Base64 EncoderEncode and decode Base64 text safely.Percentage CalculatorX% of Y, % change, % increase/decrease.BMI CalculatorBody Mass Index with imperial & metric.Loan CalculatorMonthly payment, total interest, amortization.Profit Margin CalculatorGross profit, margin, and markup from revenue and cost.Markup CalculatorSelling price, profit, and margin from cost and markup.VAT / GST CalculatorAdd or remove VAT, GST, sales tax, or service tax.ROI CalculatorReturn on investment, net gain, and return multiple.Break Even CalculatorBreak-even units and revenue for pricing decisions.Age CalculatorExact age in years, months, days.Tip CalculatorTip splits, per-person totals, rounding.Acre Feet to MCM ConverterConvert acre-feet of water volume to million cubic metres.

Field conditions

Local-first principles

Every tool runs 100% client-side — files never leave your browser.

No account, no sign-up, no usage limits.

Heavy lifting is done with WebAssembly and native browser APIs — DuckDB-WASM, Web Crypto, File System Access.

Tools work offline once the page has loaded.

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Case studies, references and working notes — all available on request.Case files, references and field reports — all declassified on request.

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