Developer instruments.
Ready before you are.
46 fast, focused utilities for code, CSS, docs, and systems work. Private by default — open one, paste, done. No sign-ups, no clutter, no waiting.
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All developer tools
Beautify, minify, and validate JSON payloads with live syntax highlighting.
Syntax Converter (JSON to Code)
Convert raw JSON into type-safe TypeScript, Dart, Python, Go, Kotlin, C#, or Rust models instantly.
Convert Excel and XLS spreadsheets to JSON, or turn JSON arrays into downloadable .xlsx workbooks — batch, multi-sheet, and fully in-browser.
Extract text, page structure, and metadata from PDF files into clean structured JSON — batch multiple PDFs at once, all in your browser.
Copy text from images, screenshots, photos, and scanned documents in 30+ languages — batch many images at once, powered by Tesseract OCR running entirely in your browser.
Remove owner-password restrictions or strip a known user password from PDF files — batch multiple PDFs at once, entirely in your browser.
Encode strings and binary images to Base64 format or decode them back safely.
Encode query parameters and paths for query strings, or decode URI-encoded targets.
Add UTM tags (source, medium, campaign) to any link, build tracked campaign URLs in bulk, or parse an existing URL's parameters — all in your browser.
Decode JSON Web Tokens to inspect header configs, claim payloads, and expiry times — or encode and HMAC-sign new HS256/HS384/HS512 tokens, all in your browser.
Test regular expressions live with highlight overlays, match group breakdowns, and a library of common patterns (email, URL, phone, IPv4, hex color).
Create cryptographically secure passwords, UUIDs, MD5 and SHA256 hashes.
Convert JSON to YAML and YAML to JSON instantly in your browser — ideal for Docker Compose, Kubernetes manifests, and CI/CD pipeline configs.
Format, beautify, and validate YAML in your browser — with dedicated builders and schema checks for OpenAPI specs and GitLab CI (.gitlab-ci.yml) pipelines.
Turn JSON arrays into spreadsheet-ready CSV files or parse CSV exports back into structured JSON, with delimiter options and type detection.
Beautify messy SQL queries with dialect-aware formatting for PostgreSQL, MySQL, SQLite, and more — or minify them to a single line.
Validate XML syntax and beautify or minify documents with clean indentation — built for RSS feeds, sitemaps, and SOAP payloads.
Compare two blocks of text, code, or JSON side-by-side and highlight every added or removed line — nothing ever leaves your browser.
Convert text to camelCase, snake_case, kebab-case, PascalCase, CONSTANT_CASE, Title Case, and more — every variant generated at once.
Escape special characters into named, decimal, or hex HTML entities — or decode entity-encoded strings back to plain text.
Generate random v4 UUIDs or time-ordered v7 UUIDs in bulk — up to 1000 at once, cryptographically secure, with copy-all and .txt export.
Generate fluid SVG wave graphs and random organic blobs for design backdrops.
Paste, edit, visualize, and optimize raw SVG vector codes dynamically with viewport checkered grids, zooming, and XML formatting tools.
Convert PNG, JPG, and WebP images to scalable SVG vectors, or render SVG to high-resolution raster images — batch many at once, entirely in your browser.
CSS Shadow, Neumorphism & Glassmorphism
Craft layered box-shadows, soft neumorphic surfaces, or frosted glassmorphism — with a live preview and cross-browser CSS.
Generate rich multi-stop gradients and customized Keyframe animation matrices.
Create trending custom color palettes, check contrast ratios, and copy CSS/Tailwind codes.
Extract a dominant-color palette from any photo — drop several images at once and pull HEX swatches from each, entirely in your browser.
Website Color Scheme Generator
Turn one brand color into a full website palette — primary, accent, surfaces, and text roles — with a live UI preview and copy-ready CSS or Tailwind.
Batch crop, resize, filter, and compress images with Squoosh codecs — PNG, JPEG, WebP, AVIF, and Base64 — entirely in your browser, with one-click ZIP export.
Convert PDF pages to PNG or JPG images, or combine a batch of photos into one PDF — fully client-side, no upload.
Visually configure Flexbox and Grid layouts — direction, alignment, gaps, columns — with a live preview and copy-ready boilerplate CSS.
Border Radius & Blob Generator
Fine-tune per-corner border radii or sculpt organic blob shapes with the full 8-value border-radius syntax and live preview.
Design the frosted-glass UI effect visually — backdrop blur, transparency, saturation, and borders — and copy cross-browser CSS.
Instantly convert any color between HEX, RGB, HSL, and CMYK formats — paste any notation or pick visually with a live swatch.
Visualize what your website metadata and Open Graph settings will look like when shared on Google, Facebook, X (Twitter), and LinkedIn.
Upload design screenshots and wrap them in elegant, interactive browser or mobile device mockups.
Paste raw code and export stunning, highly customized snippet cards ready to share.
Compose standard Markdown documentation with live rendering side-by-side.
Generate premium, multi-format favicon assets and app icons from text, emojis, or uploaded images with browser tab and mobile homescreen live mockups.
Lorem Ipsum & Dummy Data Generator
Generate placeholder paragraphs, sentences, and words — or realistic dummy JSON records with names, emails, and addresses for UI mockups.
Create downloadable QR codes for URLs, WiFi networks, and vCard contacts with custom colors — exported as crisp PNG or scalable SVG.
Easily decode or compile cron expressions into readable scheduling plans.
Calculate Chmod file permissions using interactive checkboxes or numeric symbols.
Compute CIDR subnet ranges and perform simple domain name mappings.
Epoch / Unix Timestamp Converter
Convert Unix timestamps to human-readable dates and back, with a live epoch clock and auto-detection of seconds, milliseconds, and nanoseconds.
Privacy-first developer tools that run entirely in your browser
Mentigo is a collection of 46+ free developer and designer utilities built privacy-first and secure by design. Every tool runs entirely client-side, so your JSON payloads, JWT tokens, images, and code never leave your machine — there is nothing to upload, no account to create, and no processing queue to wait in. Open a tool, paste or drop your input, and copy the result.
Every utility is built for real developer workflows: keyboard-first navigation, instant results as you type, and batch processing where it matters — like converting or compressing many images at once instead of one file at a time.
Your data never leaves your device
Privacy and security come first. Because every tool runs locally in your browser, sensitive inputs — API tokens, credentials, private keys, customer data, source code — are processed on your own machine and are never transmitted to a server, logged, or stored by us. There are no accounts, no cookies tracking what you paste, and no analytics on the content you work with. Many tools keep working even after you go offline.
JSON formatter, converters & decoders
Format and validate JSON, convert JSON to TypeScript interfaces, YAML, or CSV, encode and decode Base64, inspect JWT tokens, generate UUIDs, diff text, and format SQL or XML — the everyday code utilities, all in one place.
CSS & SVG generators
Design box shadows, border radii, and glassmorphism effects with live preview, convert colors between HEX, RGB, and HSL, and generate organic SVG blobs and waveforms — then copy production-ready CSS or markup with one click.
Image, mockup & documentation tools
Batch-convert and compress images to WebP or AVIF, frame screenshots in device mockups, generate favicons and QR codes, and produce beautiful code images for docs, presentations, and READMEs.
System & network calculators
Build cron expressions, calculate chmod file permissions, convert Unix timestamps, and run DNS and subnet lookups — quick answers for the systems side of the job.