DevKit: JSON, JWT & Dev Tools

Offline Formatter & Debugger

Free · In-App Purchases · Designed for iPad. Not verified for macOS.

30+ developer tools in one app — JSON, Base64, JWT, hashes & more. 100% offline, privacy-first. No data ever leaves your device. DevKit puts 30 developer utilities in your pocket — and every one runs entirely on your device. Stop juggling browser tabs. Stop pasting production tokens into random websites. Format JSON, decode a JWT, test a regex, or convert a timestamp on a train, on a plane, or inside a locked-down corporate network. YOUR WORK STAYS ON YOUR DEVICE > Every tool runs locally. The JSON you paste, the token you decode, the certificate you inspect — none of it is uploaded to a server, and none of it is visible to us. > All 30 tools work with no internet connection. > No account, no sign-up, no email required. FORMATTERS > JSON Formatter: Beautify or minify JSON with error highlighting and tree view > HTML Formatter: Beautify, minify, and preview HTML with live rendering > CSS Formatter: Format and validate CSS with syntax highlighting > JS Formatter: Format and minify JavaScript > XML Formatter: Format and validate XML documents > SQL Formatter: Format and validate SQL queries PARSERS & DEBUGGERS > JWT Debugger: Decode tokens, inspect headers and payloads, verify signatures > Cron Parser: Parse cron expressions with next run calculations > Certificate Decoder: Decode X.509 certificates ENCODERS & DECODERS > Base64: Encode and decode Base64 strings > URL Encoder: Encode, decode, and parse URLs > HTML Encoder: Handle HTML entities > Hash Generator: Generate MD5, SHA-1, SHA-256, SHA-512 hashes > Backslash Escape: Escape and unescape special characters CONVERTERS > Timestamp: Convert Unix epoch timestamps to readable dates > Case Converter: Transform between camelCase, snake_case, UPPER CASE, and more > Color Converter: Convert between HEX, RGB, HSL with live preview > YAML to JSON: Convert between YAML and JSON with tree view > Number Base: Convert between Binary, Octal, Decimal, Hexadecimal > Hex to Text: Convert between hex and ASCII > CSV to JSON: Convert between CSV and JSON GENERATORS > UUID/ULID Generator: Create UUIDs and ULIDs instantly > QR Code: Generate customizable QR codes and export as images > Lorem Ipsum: Generate placeholder text > Random String: Generate secure passwords and API keys TEXT & COMPARISON > Diff Checker: Compare text with highlighted differences > RegEx Tester: Test regex with live match highlighting > Markdown Previewer: Preview Markdown with GitHub Flavored support > Line Sort: Sort and deduplicate lines > String Inspector: Analyze string statistics BUILT FOR MOBILE > Smart History: Auto-saves recent work, stored only on your device > Instant Paste: Smart clipboard detection > Quick Actions: One-tap copy, clear, share > Native Performance: Blazing fast, no loading screens > Light & Dark Modes: Beautiful design for any environment WHO IT'S FOR > Software engineers debugging away from a desk > Site reliability engineers checking cron schedules and certificates during an incident > Backend developers inspecting tokens and payloads > Engineering managers reviewing a diff or a config between meetings > Anyone who needs dev tools without a network PRICING Pro: $9.99/month or $39.99/year (save 67%) 3-day free trial. Cancel anytime. WHY DEVKIT > Works with no connection > Your work never leaves the device > Fast, native performance > Regular updates with new tools > No ads, ever > Built by a developer, for developers Download DevKit and take your tools anywhere. Terms of Use: Apple's Standard EULA (https://www.apple.com/legal/internet-services/itunes/dev/stdeula/)

Ratings & Reviews

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UI/UX improvements, bug fixes

Version 1.0.7

The developer, Alexander Herdt, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Linked to You

    The following data may be collected and linked to your identity:

    • Location
    • Identifiers
    • Usage Data

  • Data Not Linked to You

    The following data may be collected but it is not linked to your identity:

    • Purchases
    • User Content
    • Usage Data
    • Diagnostics

Privacy practices may vary based, for example, on the features you use or your age. Learn More

Accessibility

The developer has not yet indicated which accessibility features this app supports. Learn More

Information

Provider
  • Alexander Herdt
Size
  • 54.1 MB
Category
  • Developer Tools
Compatibility
Requires iOS 15.1 or later.
  • iPhone
    Requires iOS 15.1 or later.
  • iPad
    Requires iPadOS 15.1 or later.
  • iPod touch
    Requires iOS 15.1 or later.
  • Mac
    Requires macOS 12.0 or later and a Mac with Apple M1 chip or later.
Languages
  • English
Age Rating
4+
In-App Purchases
Yes
  • Pro Monthly SAR 39.99
  • Pro Yearly SAR 179.99
  • Learn More
Copyright
  • © 2025 Alex Herdt
  • Developer Website
  • Privacy Policy

    • More by Alexander Herdt

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