EPUB Fix repairs ebook files that won't open, display garbled text, or get rejected by Apple Books — all directly on your iPhone. It automatically regenerates the mimetype file and adds missing language tags to content.opf, then repackages everything into a spec-compliant EPUB ready to share or save. Five repairs free, then watch a short ad to keep going — no subscription, no desktop required.
The app regenerates the mimetype file with the exact ASCII string the EPUB spec requires, and adds a missing dc:language tag to content.opf when one isn't present. Both fixes are applied automatically — no manual editing needed.
Once repair is complete, tap "Share / Open in Books" to send the fixed EPUB straight to Apple Books via iOS's native share sheet — or use AirDrop, Mail, or any other app. A separate Save button exports the file using the system file exporter.
The first five repairs are completely free. After that, watch a short rewarded ad to unlock one more repair — no subscription, no in-app purchase, no limit on how many times you can use the app over time.
EPUBs are ZIP archives. The app unpacks the file, finds the correct root even inside nested folder structures, applies its fixes, and repackages everything into a valid EPUB with mimetype stored uncompressed at position zero, as the spec requires.
The repair pipeline runs two operations. First, it deletes any existing mimetype file and writes a fresh one containing only the ASCII string "application/epub+zip" — no BOM, no trailing whitespace. Second, it scans content.opf for a dc:language element; if one is missing, it inserts one before the closing metadata tag. If a language tag already exists, the file is left untouched. Both fixes preserve the original encoding of the OPF file, whether UTF-8, UTF-16, or anything else.
The selected EPUB is copied to a temporary working directory and unzipped. The app handles single-folder-wrapped archives by detecting and descending into the actual EPUB root automatically. Hidden files and __MACOSX metadata are excluded from the output. After fixing, the files are repackaged into a new ZIP archive with mimetype added first using no compression — exactly as required by the EPUB 3 specification — and the rest of the contents stored with standard deflate compression.
When repair finishes, two action buttons appear. "Share / Open in Books" opens the iOS share sheet with the fixed EPUB attached, letting you send it to Apple Books, AirDrop it to another device, attach it to an email, or open it in any app that handles EPUB files. "Save repaired file" invokes the system file exporter with a pre-filled filename based on the original, with "-fix" appended. The app cleans up all temporary files automatically on launch.
Usage is tracked locally with a simple counter. The first five repairs are free with no restrictions. Once the counter reaches five, a consent sheet appears before the next repair. Tapping "Watch ad & repair" loads a rewarded ad — the button shows a loading indicator until the ad is ready, and is disabled while loading to prevent accidental taps. After the ad plays through, the repair runs automatically. The counter increments only after a repair actually completes, so cancelled or failed ads don't count against you.
Tap "Open EPUB File" to launch the file picker. Select the .epub file you want to repair. If you select a non-EPUB file by mistake, the app will show an alert and let you try again.
The app unpacks the file, applies the necessary fixes, and repackages it automatically. A status indicator shows each stage — preparing, analysing, repairing. When complete, a confirmation message appears.
Tap "Share / Open in Books" to send the repaired EPUB to Apple Books or another app, or tap "Save repaired file" to export it to your Files app. After five free repairs, watch a short ad to continue — no subscription needed.
"An EPUB I'd been trying to open in Books for weeks was fixed in about ten seconds. I had no idea the mimetype file could cause so many problems. Simple app, does exactly what it says."
"I had a batch of older EPUB files that kept throwing errors. This app sorted them out one by one without any fuss. Love that you can just watch an ad instead of paying — very fair model."
"No technical knowledge required at all. You pick the file, it repairs it, you send it to Books. The whole process takes maybe 15 seconds. Exactly the kind of utility app the App Store needs more of."
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