Free Online Developer Tools
Fast, secure, and privacy-friendly tools that run entirely in your browser. No sign-up. No data sent to our servers.
All Tools
📝 Text
JSON Viewer
Explore JSON with interactive syntax highlighting and tree view.
JSON Formatter
Format and minify JSON with custom indentation.
Word Counter
Count words, characters, sentences and reading time.
Lorem Ipsum
Generate placeholder Lorem Ipsum text in words, sentences, or paragraphs.
Slug Generator
Convert any title into a clean, SEO-friendly URL slug.
Case Converter
Convert text between UPPER, lower, camelCase, snake_case and 7 more formats.
ROT13
Encode or decode text using the ROT13 substitution cipher.
Text Diff
Compare two texts line by line with added/removed highlighting.
🔐 Encode / Decode
Base64
Encode or decode UTF-8 text and files to/from Base64.
Base32
RFC 4648 Base32 encoder and decoder with UTF-8 support.
URL Encoder
Percent-encode or decode URLs using encodeURIComponent.
HTML Entities
Encode/decode HTML entities — named, decimal, and hex.
Image → Base64
Convert any image to a Base64 data URL for embedding in CSS/HTML.
Unicode Inspector
Inspect Unicode code points, UTF-8 bytes and HTML entities for any text or emoji.
📦 JSON / Data
JSON → TypeScript
Convert JSON objects to TypeScript interfaces with nested type inference.
JSON Diff
Compare two JSON objects and highlight added, removed, and changed fields.
JSON Schema
Generate JSON Schema Draft 7 from any JSON with type & format inference.
SQL Formatter
Format and beautify SQL queries with configurable indentation.
CSV ↔ JSON
Convert CSV to JSON and JSON arrays to CSV with type inference.
Markdown Preview
Live Markdown editor with side-by-side HTML preview.
🔒 Security
⚙️ Dev Utils
UUID Generator
Generate cryptographically secure UUID v4 identifiers in bulk.
Regex Tester
Live JavaScript regex tester with match highlighting and flags.
Number Base
Convert numbers between decimal, hex, octal, and binary.
Timestamp
Convert Unix timestamps to dates and vice versa.
QR Code
Generate QR codes for URLs, WiFi, emails — download PNG/SVG.
Color Converter
Convert colors between HEX, RGB, HSL with a color picker.
Color Palette
Generate Tailwind-style color shades and harmonies from any HEX color.
Fake Data
Generate realistic fake user records for testing. Export JSON or CSV.
CRON Builder
Build CRON expressions visually with presets and human-readable descriptions.
🌐 Network / API
Curl to Code
Convert cURL commands to JavaScript, Python, Go, or PHP code.
Meta Tags Preview
Build SEO meta tags, OG, and Twitter Cards with live preview.
DNS Lookup
Check A, AAAA, MX, NS, TXT, CNAME records via Cloudflare DoH.
HTTP Headers
Inspect HTTP response headers and audit for missing security headers.
IP Address Info
Get geolocation, ISP, timezone, and country for any IP address.
GraphQL Builder
Build queries, mutations, and subscriptions visually.
OpenAPI Viewer
Explore OpenAPI/Swagger specs with a visual endpoint explorer.
Why StackUtils?
We built this platform for developers who need reliable, lightweight tools without ads interrupting their workflow. Every tool works offline-capable and processes data directly in your browser.
⚡ Blazing Fast
Built on Next.js with zero-latency client-side processing. No waiting for server round-trips.
🔒 Privacy First
Your data never leaves your browser. We don't log, store, or analyze your inputs.
🆓 Always Free
All core tools are and will remain free. Supported by non-intrusive ads.