HTML5 Viewer

Two tools one app

Only for Mac

Free · In‑App Purchases

Mac

HTML Editor is a focused native Mac app for the last mile of shipping to the App Store: writing and polishing HTML, and turning your screenshots into every size Apple asks for. Two tools live inside one quiet window. THE EDITOR • Open any .html, .htm, .css, or .js file. • See it rendered instantly in a live WebKit preview next to your code. • HTML syntax highlighting — tags, attributes, strings, comments. • Line numbers that stay readable at every font size. • Monospace font with adjustable size from 10 to 24 points. • Word wrap toggle, built-in find bar, multi-level undo. • Open and save with standard macOS file dialogs. • Keyboard shortcuts: ⌘N new, ⌘O open, ⌘S save, ⇧⌘S save as. No dev server, no Node, no build step, no login. Just a native window and your file. THE SCREENSHOT CONVERTER Drag your screenshots in, pick a device, press Export. Every App Store Connect screenshot size Apple asks for is built in: • iPhone — 6.9″ (16 Pro Max), 6.7″, 6.5″, 5.5″, 4.7″ • iPad — 13″ (M4), 12.9″, 11″, 10.5″ • Mac — 2880×1800, 2560×1600, 1440×900, 1280×800 • Apple Watch — Ultra 49mm through Series 3 40mm • Apple TV — HD and 4K • Apple Vision Pro • Custom — any width × height in pixels Three fit modes: • Fit — letterbox with a background color of your choice • Fill — scale and crop to fill the frame • Stretch — exact target dimensions Export to PNG or JPEG with an adjustable quality slider. Batch-process a whole folder in one pass. Output files are auto-named with the target dimensions, ready to upload. PRIVACY, BY DEFAULT HTML Editor runs entirely on your Mac. • No accounts, no sign-in, no profiles. • No analytics, no telemetry, no third-party SDKs, no advertising. • No network requests made by the app itself. • Files stay on your Mac — the app runs in Apple's sandbox with only user-selected file access. • Screenshot conversion happens on-device with Core Graphics. Your code is your code. Your screenshots are your screenshots. REQUIREMENTS macOS 14 Sonoma or later. Universal binary — runs natively on Apple Silicon and Intel.

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Version 1.6 — a calmer preview, a much faster editor on big files, and regular expressions in Find. PREVIEW • The preview no longer reloads on every keystroke. It waits for a pause in typing, so a long page stops flickering while you work. • It keeps your place. Editing something halfway down a page no longer throws the preview back to the top — it holds position while the page re-renders, including pages that build themselves with JavaScript. • If the preview ever goes blank because its web process was shut down, it now reloads itself instead of staying empty until you press Reload. EDITOR • Much faster syntax highlighting on large documents. A 1,000-line file took about 120 ms per keystroke and now takes under 10 — the difference between a visible stutter and none. Only the part you can see is re-coloured, while the rest of the document is still read so comments and tags that start off-screen stay correct. • New: Find and Replace does regular expressions. • New: Go to Line. Press cmd+L, pick it from the Edit menu, or click the line and column indicator in the status bar. • New: the status bar shows the line and column of the cursor. • Files that aren't UTF-8 now open from the Open menu, not only by double-clicking them in Finder. UTF-16 and other encodings are recognised rather than refused. RECENT FILES • New: your recent documents are listed in the sidebar, with enough of the folder path to tell two index.html files apart. Right-click to remove one or reveal it in Finder. They're also in File ▸ Open Recent. SCREENSHOT CONVERTER • Long titles now wrap instead of shrinking. A headline that used to be squeezed to 40% of its size to fit on one line is now set at full size across two or three lines. Short titles are unchanged.

The developer, Opticell Limited, 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 Not Collected

    The developer does not collect any data from this app.

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

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

    Seller
    • Opticell Limited
    Size
    • 1.4 MB
    Category
    • Developer Tools
    Compatibility
    Requires macOS 14.0 or later.
    • Mac
      Requires macOS 14.0 or later.
    Languages
    • English
    Age Rating
    4+
    In-App Purchases
    Yes
    Copyright
    • © 2026 Opticell Ltd.