KNothing

A collection of free online developer tools that run entirely in the browser, solving the problem of data privacy and security when using web-based utilities. It targets developers, IT professionals, and operations teams, as well as individual users and businesses of all sizes. The tools are positioned as a privacy-first alternative to traditional online tools, with 100% client-side processing, no server uploads, and no tracking.

Key features

• Bulk generate v4 UUIDs
• Validate and beautify JSON
• Create beautiful code screenshots
• Visual cron scheduler
• One-to-one file transfer without installation
• Encode/decode text and images to base64
• Compare text differences
• Generate secure random passwords
• Convert epoch time to date
• Convert YAML to JSON locally
• Convert JSON to YAML locally
• Convert JSON to TypeScript, Go, Kotlin types
• Analyze CSV/JSON/Parquet files locally
• Debug SQLite files locally
• Securely decode JWTs offline
• Compress images to specific size
• Convert WebP/PNG to JPG
• Convert HEIC to JPG
• Download YouTube thumbnails in 4K
• Generate customizable QR codes
• Record screen with no watermarks
• Record audio locally (WebM)
• Convert audio offline (MP3, WAV, FLAC, RAW)
• Split long videos into short clips offline
• Add text or image watermark to photos
• Remove edge watermarks offline
• Create 9-grid images for WeChat Moments
• Create video covers for social platforms
• Compress PDF to target size
• Convert PDF pages to JPG