DevKit vs JSON Viewer
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
DevKit
This app provides a suite of offline developer tools for formatting, debugging, encoding, and converting data. It keeps all your work on your device, ensuring privacy and accessibility without an internet connection. Features include JSON formatting, JWT decoding, hash generation, and QR code creation.
- 30+ offline developer utilities
- JSON, HTML, CSS, JS, XML, SQL formatting
- JWT decoding and certificate inspection
- Base64, URL, and HTML encoding/decoding
- Hash generation (MD5, SHA-256)
- Timestamp and number base conversion
- QR code generation
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Convert files and debug code in one app. DevKit turns PDFs into editable Word documents, photos into PDFs and HEIC photos into JPGs, and gives developers a full kit of formatters, decoders and generators. Everything runs on your iPhone or iPad: your files are never uploaded. FILE TOOLS > PDF to Word: Turn a PDF into an editable Word document (.docx), keeping headings, lists, links, images, headers and footers. Preview the result before you save it. Scanned pages are read with on-device text recognition. Tables are kept on iOS 26 and later. > JPG to PDF: Combine photos and scans into one tidy PDF > HEIC to JPG: Turn iPhone photos into JPGs for forms and websites > MOV to MP4: Turn .mov videos into .mp4 files > HTML Viewer: Open .html files safely and see their source > JSON, XML and CSV Viewers: Open data files as a tree or a table > Unzip and Zip Files: Open .zip archives, or bundle files into one > Open files straight from the Files app, Mail or Safari, and find everything you convert in the Files tab FORMATTERS > JSON Formatter: Format, minify and validate JSON, with a collapsible tree view > HTML, CSS, JavaScript, XML and SQL Formatters ENCODE & DECODE > JWT Debugger: Decode tokens, inspect headers and claims, verify signatures > Certificate Decoder: Read X.509 certificates > Base64, URL Encoder and Parser, HTML Encoder, Backslash Escape > Hash Generator: MD5, SHA-1, SHA-256 and SHA-512 CONVERTERS > Timestamp, Case Converter, Color Converter (HEX, RGB, HSL) > YAML to JSON, CSV to JSON, Number Base, Hex to Text > Cron Parser: Read cron expressions in plain English, with the next run times GENERATE & COMPARE > QR Code: Scan codes live with the camera or from a photo, and create your own > UUID and ULID Generator, Random String, Lorem Ipsum > Diff Checker, RegEx Tester, Markdown Previewer, Line Sort, String Inspector MADE FOR YOUR PHONE > History reopens your recent runs, stored only on your device > Paste, copy and share in one tap > Light and dark designs, large text and VoiceOver support > No account and no sign-up PRIVACY The tools process your text and files on your device. DevKit uses analytics to learn which tools are used (never what you put in them); you can turn it off in Profile > Privacy & Data. SUBSCRIPTION DevKit Pro unlocks every tool, as a monthly or yearly auto-renewing subscription. The price for your country is shown in the app before you buy. Eligible new subscribers get a free trial. Payment is charged to your Apple ID account when you confirm the purchase, or when the trial ends. The subscription renews automatically unless you cancel at least 24 hours before the end of the current period. Manage or cancel it in your App Store account settings. Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://devkitpro.app/privacy
JSON Viewer
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Paste a JSON blob — an API response, a config file, a log payload — and JSONView turns it into a collapsible, colour-coded tree the moment it lands. Validate it with an error that names the exact line and column, format or minify it, and copy it back out. Everything happens on your iPhone, offline, so your payload never touches a web tool. Most JSON apps wrap the same lenient system parser. JSONView ships its own strict RFC 8259 engine: it preserves your key order instead of scrambling it, keeps number literals exactly as written, rejects the trailing commas other parsers silently swallow, and warns you about duplicate keys — with the position of both copies. WHAT YOU GET • Paste an API response and read it as a collapsible tree in under a second, with keys, strings, numbers and booleans each in their own colour • Broken JSON tells you exactly where: "Line 14, column 27 — trailing comma before '}'" instead of a shrug • Duplicate keys are flagged with both positions, so the bug that only bites in production gets caught on your phone • Find any key or value in a deep payload and jump to it with its full $.path[3].to.node • One tap copies a value, its path, or the whole document — pretty-printed or minified — to the clipboard • Round-tripping never rewrites your data: key order survives, 1e3 stays 1e3, -0 stays -0 PERFECT FOR • Backend and mobile developers checking an API response away from the desk • QA engineers pinning down exactly which field broke the build • Support and ops engineers reading the log payloads customers send in • Anyone learning what valid JSON actually is, from a parser that explains every rejection WHY NOT JUST A WEB FORMATTER? Every browser JSON tool means pasting your payload — auth tokens, emails, customer records — into someone else's server. JSONView parses entirely on-device and works in airplane mode. It also opens .json files straight from Files, Mail or Slack, so you skip the copy-paste dance entirely. PRIVATE BY DEFAULT No network calls. No account. Your documents are parsed and stored only on your iPhone, and your saved library never leaves the device. FULL ACCESS JSONView Pro unlocks the complete toolkit: an unlimited saved-document library, minify to clipboard, .json file export, custom indent width, and A-to-Z key sorting. Choose a weekly plan, a yearly plan, or a one-time lifetime purchase. Weekly and yearly plans are auto-renewing subscriptions; lifetime is a single payment. Copy a JSON payload, open JSONView, and tap Paste — the tree is already waiting. Terms of Use: https://leanstudio.asia/terms-of-use Privacy Policy: https://leanstudio.asia/privacy-policy Support: support@leanstudio.asia
Screenshots
Verdict
The clearest difference is in-app purchases: JSON Viewer at none against DevKit's 2. DevKit's advantage is update cadence (every 8 days vs every 4 months) and device support (3 vs 1). On price and ads there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. DevKit sells 2 in-app purchases, starting at $9.99 per month. JSON Viewer asks for nothing beyond the download.
DevKit ships an update every 8 days, JSON Viewer every 4 months. Both last shipped on November 5, 2026.
| Parameter | DevKit | JSON Viewer |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (3 ratings) — better | — |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 3 — better | — |
| Update frequency | Every 8 days — better | Every 4 months |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Freemium | — |
| Devices | iPhone, iPad, iPod — better | iPhone |
| Requires iOS | 15.1 — better | 17.0 |
| Further details — not scored | ||
| Size | 57 MB | 4 MB |
| Age rating | 4+ | 4+ |
| Developer | Alexander Herdt | LEAN ASIA CO., LTD |
In-app purchases
DevKit
- Pro Monthly3 Days trial$9.991 Month
- Pro Yearly3 Days trial$39.991 Year
JSON Viewer
No in-app purchases









