App Overview

DevKit: JSON, JWT & Dev Tools icon

DevKit: JSON, JWT & Dev Tools

Alexander Herdt · Developer Tools

DevKit puts 30 developer utilities in your pocket — and every one runs entirely on your device.

Free · In-app purchases

PRICE
Free
In-app purchases
BUSINESS MODEL
Freemium
No overall Grossing estimate available
RATING
5.0
3 ratings · Top 5%

Evidence scope: No current overall US chart position is available. Category-chart positions shown in discovery are a separate scope. Revenue is a directional model estimate, not verified earnings.

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Build Kit

Make this idea yours

A product spec, screen plans, and build steps for your coding agent.

First kit free with a verified email

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Combine features and design from your favorite apps.

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What's included17 files

A product spec, phased build plan, differentiation notes, and screen references.

  • START_HERE
  • AGENTS
  • EVIDENCE
  • SPEC
  • BUILD_PLAN
  • DIFFERENTIATION
  • skills/
  • screens/
Preview a sample Build Kit No email needed

Illustrative example: an invoice app for independent contractors. Your kit is tailored to the app you choose; this is not its generated content.

Feature spec

Goal: Send a clear invoice after finishing a job.

  • Add a client, line items, a due date, and payment instructions.
  • Preview the total before exporting a PDF.
  • Keep an editable draft if export fails.

Screen plan

Invoice editor: Client at the top, editable line items in the middle, total and preview action at the bottom.

States: Empty draft, validation errors beside each field, exporting, and a retry action that preserves the draft.

Differentiate and validate

Hypothesis: Contractors need faster repeat invoices more than more templates.

First experiment: Test duplicating a previous job with five contractors. Watch where they hesitate before expanding the feature set.

The full kit adds a phased build plan, evidence notes, tool prompts, and implementation guidance. It is a plan for your coding agent, not a finished app.

Usage: Mechanics are fair game; never reuse the original name, branding, assets, or verbatim copy.

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Free quick prompt For a smaller starting point

Quick prompt

> SELECT BUILD PLATFORM:

Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.

// RORK SYSTEM PROMPT
Rork plan preview for DevKit: JSON, JWT & Dev Tools: map the core Developer Tools workflow, choose the smallest differentiated feature set, define the data and monetization boundaries, then prototype the riskiest user journey first.
            

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Opportunities

AI-GENERATED OPPORTUNITY HYPOTHESES

These are generated suggestions, not verified review quotations. Check current App Store reviews and speak with users before treating a possible gap as a requirement.

Hypothesis 1

Provide real-time notifications or loading indicators.

Assumption to check: Lack of user feedback on tool execution

Validate with people who use this workflow before building.

Hypothesis 2

Regularly update the toolset with user-requested features.

Assumption to check: Limited tools available

Validate with people who use this workflow before building.

Hypothesis 3

Implement analytics to provide insights to users.

Assumption to check: No detailed analytics on tool usage

Validate with people who use this workflow before building.

Hypothesis 4

Simplify navigation and enhance onboarding experience.

Assumption to check: Confusing navigation structure

Validate with people who use this workflow before building.

App evidence

Original App Store material. Ratings and screenshots describe the existing app, not proof of demand for your version.

App Store description

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/)

Written user reviews are not shown here. Check current App Store reviews >

Screenshots

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Build scope

Plan a focused first version with your coding agent. These are planning assumptions, not a delivery guarantee.

Define the first version

Choose one audience and one core workflow. Use the kit to agree on its screens, data, and acceptance criteria before building.

Set boundaries

Decide which secondary features, integrations, and platform support can wait. Your version does not need to reproduce everything in the original.

Check the hard parts

Validate external services, specialist technology, data access, and ongoing costs for your chosen scope.

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BUILD KIT DIFFICULTY
Starter

From the Build Kit assessment.

A reliable timeline needs an agreed scope and a technical check. Ask your agent to estimate the phases in BUILD_PLAN.md after that review.