Send to X4 vs Spine
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Send to X4
Wirelessly send articles, notes, and custom screensavers to your e-ink reader. Convert web content to EPUBs, import your own files, and manage content directly on the device. Enjoy a private, cloud-free experience over local WiFi.
- Convert articles to EPUB
- Import custom EPUB files
- Send text notes
- Design custom screensavers
- Browse e-ink wallpapers
- Manage device files
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Your all-in-one companion for the Xteink X4 e-ink reader. Send articles, notes, custom screensavers, and EPUB files — all over WiFi, with zero cloud accounts. • ARTICLES TO EPUB IN SECONDS Paste any URL or tap Share from your browser. Send to X4 strips ads and clutter, then converts articles into clean EPUBs optimized for e-ink. Supports threads, long-form content, and image-rich pages. Queue multiple articles and batch-send them all at once — even pre-download them for offline sending later. • IMPORT YOUR OWN EPUBs Already have EPUB files? Pick them from your device and send them straight to the X4. No conversion needed. • QUICK NOTES Type or paste any text and send it to your X4 as a .txt file. Perfect for meeting notes, to-do lists, or reading lists. Drafts are saved automatically. • SLEEP SCREEN DESIGNER Create your own lock screen with the built-in editor. Add text, images, and freehand doodles. Use the Sign mode for full-screen to-do lists that auto-size to fill the display. Enable "Overwrite Default" to always replace the same file — your X4 lock screen becomes a living to-do list. • >1,000+ E-INK WALLPAPERS Browse curated wallpapers from x4ePapers (lowio.xyz and readme.club). Preview, send, or try a random pick. New wallpapers added regularly. • PHOTOS TO SCREENSAVERS Pick any photo from your gallery. It is automatically cropped, resized, and converted to a 480x800 BMP ready for the X4 display. • DEVICE FILE MANAGER Browse articles, notes, and screensavers already on the device. Preview sleep screen thumbnails. Swipe to delete files you no longer need. • 100% PRIVATE Everything transfers over local WiFi. No cloud. No accounts. No tracking. Your data stays between your phone and your X4. • WORKS WITH ALL FIRMWARE Full support for both Stock and CrossPoint firmware. Configurable IP, custom storage folders, and optional date-based subfolders to keep everything organized.
Spine
This app enhances audiobook listening with features like listener levels, daily streaks, and shareable year-end recaps. It offers a beautiful, integrated player and syncs with Hardcover, all while keeping your data private on-device.
- Integrated audiobook player
- Listener levels and daily streaks
- Hardcover sync
- On-device AI summaries
- Shareable year-in-review recap
- Lock screen and widget controls
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Spine is the audiobook app you'll actually leave open. It streams from your own cloud library, syncs with Hardcover, and turns the habit of listening into something worth coming back to with listener levels, daily streaks, and a year-in-review Recap bright enough to share. Built native for iOS 26, with Liquid Glass, serif typography, and a player carved into the book's detail page. No subscription. No ads. No in-app purchases. No account to create with us. Bring your own library, keep your own data. WHAT MAKES IT DIFFERENT • ONE PAGE FOR THE BOOK: No separate Now Playing screen. Cover, scrubber, transport, speed, sleep timer, chapters, and bookmarks all live inline on the detail page, on an ambient backdrop tinted by the cover. • CHAPTERS THAT JUST WORK: Single-file M4B audiobooks expose their chapters automatically. Cloud folders with multiple M4Bs split into separate library entries. No manual editing, no reprocessing. • HARDCOVER SYNC: Just listen. Spine logs progress and finished books to Hardcover, pulls cover art, genre, and structured series data, and keeps your shelves in sync. • ON-DEVICE INTELLIGENCE: Open the next book in a tracked series and Spine writes a two-sentence "previously on…" recap from what you've already finished. It also rewrites bloated marketing descriptions into a calm summary, captions your Recap, and cleans up filename-salad titles. All on Apple's on-device foundation model. Nothing about your library leaves the phone. • LEVELS, STREAKS, AND GOALS: Lifetime hours unlock six tiers, from Sapling to Oracle. A unified daily/yearly goal card, a streak chip, and a year-spanning heatmap show the shape of your habit at a glance. • A RECAP YOU'LL WANT TO SHARE: Five bright screens covering hours, finished books, top author and genre, monthly rhythm, and the books you marked Read on Hardcover. One tap stitches the whole thing into a postable image. • PLAYBACK THAT PAYS ATTENTION: Step away for a moment and Spine rewinds a few seconds when you press play. The sleep timer fades audio gently to zero. Finish a series entry and the next book surfaces automatically. • LIVE ON THE LOCK SCREEN: Live Activities follow the current book onto the Lock Screen and Dynamic Island, with a tappable Play/Pause. The home-screen widget mirrors the same control on a cover-tinted backdrop, toggle playback in one tap, even when Spine isn't running. • BOOKMARKS WORTH KEEPING: Tap to mark any moment with a written note. Tap to jump back later. • SEARCH THAT POINTS SOMEWHERE: Open the search tab cold and you get a trending-genre card tuned to what you actually listen to, a Discover list of Audible new releases, and trending shortcuts. Most people aren't searching their own shelf, they're looking for the next thing. • EVERY BOOK IS A DOORWAY: Detail pages carry "More by author", "Top in genre", and a "Part of {Series}" rail that interleaves the books you own with the Hardcover siblings you don't, in reading order, right under your bookmarks. • CLOUD LIBRARY, REPAIRED IN ONE TAP: When a cloud title expires or goes stale, Spine flags it on the detail page and offers a one-tap re-download. No re-adding, no losing your progress. • SPOTLIGHT-INDEXED: Search your library from anywhere in iOS. PRIVACY BY DEFAULT Spine has no servers, no analytics, and no third-party SDKs. API keys live in the iOS Keychain. Your library, listening history, and bookmarks stay on your device (and sync via your own iCloud, if you enable it). The on-device AI features run on Apple Intelligence — your books never leave the phone. REQUIREMENTS • iPhone running iOS 26. • A cloud audiobook library. • A free Hardcover account is recommended for metadata, search, and read sync. • Apple Intelligence-eligible device is required for the optional AI features (everything else works without it).
Screenshots
Verdict
The clearest difference is review sentiment: Send to X4 at 100% against Spine's 75%. Send to X4 also leads on update cadence (daily vs every 4 days) and rating (5.0 vs 4.8). Spine's advantage is ratings volume (25 vs 4). On price, ads, in-app purchases and monetization model 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. Neither carries in-app purchases, so what you see is what you pay.
Send to X4 holds the better App Store score, 5.0 against 4.8. That said, the two scores are not equally well evidenced: Spine has 25 ratings behind it against 4, so its average is the more settled of the two. Written reviews point the same way: 100% of Send to X4's written reviews are positive against 75% of Spine's.
Send to X4 ships an update daily, Spine every 4 days. The most recent releases landed on August 21, 2026 and September 17, 2026 respectively.
| Parameter | Send to X4 | Spine |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (4 ratings) — better | 4.8 (25 ratings) |
| Positive reviews | 100.0% of reviews — better | 75.0% of reviews |
| Number of ratings | 4 | 25 — better |
| Update frequency | Daily — better | Every 4 days |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPad, iPod — better | iPhone, Apple Watch |
| Requires iOS | 15.1 — better | 26.0 |
| Further details — not scored | ||
| Size | 34 MB | 13 MB |
| Age rating | 4+ | 12+ |
| Developer | Jaime Chapinal | Accelyze Inc. |
Customer experience
Send to X4
Spine
In-app purchases
Send to X4
No in-app purchases
Spine
No in-app purchases









