JSON Formatter
Format and beautify JSON with syntax validation and repair.
Tool collections
Common workflows grouped by task. Each collection links to the tools you reach for together — no account, all local.
Debug an API
5Format responses, inspect tokens and headers, and reproduce requests — the usual loop when an endpoint misbehaves.
Ship accessible UI
4Check contrast, generate meta tags, and preview how links appear when shared.
Color Contrast Checker
Check a11y color contrast ratios against WCAG AA and AAA thresholds.
Meta Tags Generator
Generate SEO and Open Graph meta tags with social preview.
Open Graph Preview
Extract Open Graph and meta tags from HTML.
CSS Clamp Calculator
Generate fluid clamp() values for responsive typography and spacing.
Work with config files
6Convert and validate JSON, YAML, TOML, and env templates without leaving the browser.
JSON Formatter
Format and beautify JSON with syntax validation and repair.
JSON to YAML
Convert JSON data to YAML format.
YAML to JSON
Convert YAML documents to JSON format.
TOML to JSON
Convert TOML documents to JSON format.
JSON to TOML
Convert JSON data to TOML format.
Env Template Generator
Generate .env file templates for common app setups.
Frontend security checks
6Decode JWTs, generate CORS and CSP headers, hash strings, and encrypt test payloads locally.
JWT Decoder
Decode JWT tokens and inspect header and payload.
JWT Generator
Create and sign HS256/HS384/HS512 JWT tokens locally in your browser.
CORS Header Generator
Generate CORS response headers for your API.
CSP Builder
Build Content-Security-Policy headers and meta tags for your app.
Hash Generator
Generate SHA-1, SHA-256, SHA-384, and SHA-512 hashes.
HMAC Generator
Generate HMAC-SHA256, SHA384, and SHA512 message authentication codes.
Validate SEO files
4Check robots.txt and sitemap.xml before deploy — catch crawl-blocking typos and broken sitemap URLs.
Prototype CSS fast
5Build animations, layout, shadows, and fluid type with live preview and copy-ready output.
CSS Animation Builder
Build @keyframes animations with presets, live preview, and copy-ready CSS.
CSS Transition Builder
Generate transition CSS with duration, delay, and easing — hover to preview.
Flexbox & Grid Playground
Visual flexbox and CSS grid playground with exportable CSS.
Box Shadow Generator
Build box-shadow values with sliders and live preview.
CSS Clamp Calculator
Generate fluid clamp() values for responsive typography and spacing.