free dev tools that don't phone home

Everything runs in your browser tab. No signup, no ads, no telemetry on your input. Open DevTools → Network and watch nothing happen.

tools     14
backend   none
cost      $0
    
[data]

JSON to CSV Converter

Convert JSON to CSV and back. 100% in your browser.

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[dev]

Regex Tester

Test, debug, and explain regular expressions.

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[generator]

QR Code Generator with Logo

Generate branded QR codes with a custom logo overlay.

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[image]

Image Compressor

Compress JPG, PNG, and WebP without quality loss.

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[image]

Image Size Converter

Resize JPG, PNG, and WebP to exact pixel dimensions.

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[dev]

JWT Decoder & Verifier

Decode and verify JSON Web Tokens (HS256, RS256, ES256) in your browser.

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[data]

Markdown ↔ HTML Converter

Convert GitHub-flavored Markdown to HTML and back. Live preview, syntax highlighting.

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[image]

EXIF Viewer & Stripper

Inspect and remove camera, GPS, and personal metadata from images. Lossless.

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[dev]

Color Picker & WCAG Contrast

Convert between hex, RGB, HSL, OKLCH, HWB. Check WCAG contrast. Extract palettes.

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[generator]

Favicon Generator

Generate a complete favicon set (ICO, PNG, manifest) from a single image.

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[data]

JSON Formatter & Error Reviewer

Validate, pretty-print, and minify JSON. Pinpoint syntax errors by line and column.

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[data]

JSON ↔ YAML Converter

Convert JSON to YAML and back. Kubernetes-friendly, block or flow style, sort keys.

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[dev]

Diff Checker

Compare two texts or JSON documents. Line, word, char, and JSON-aware modes.

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[dev]

Cron Expression Builder & Tester

Describe any cron expression in plain English and preview the next 10 fires in your timezone.

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# why?

Most online converters upload your data, show three ad banners, and ask for an email. This site doesn't. Every tool here is a static page with a small script that runs in your browser. Your input never leaves your device. Pages are open-source and hosted on Cloudflare's edge so they load fast from anywhere.