Comparison

Secret Delivery vs Zero Duplicates

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Secret Delivery

Securely send private messages, photos, and documents with password-protected encryption. Share files through various platforms, ensuring your sensitive information remains confidential. Recipients need the app to decrypt and access content.

Highlights
  • Encrypted text and file sharing
  • Password protection for messages and files
  • AES encryption standard
  • Encrypt/decrypt files outside the app
  • Intuitive user interface
  • Unlimited messages and file attachments
Features
Read full description

Secret Delivery encrypts your files and text so only the people you choose can read them. No accounts. No servers. No tracking. Your password never leaves your device — and neither does your data. FREE TO START • Encrypt and decrypt text messages — free, forever. • Share encrypted text as a secretdelivery:// link, or copy and paste the ciphertext anywhere. PRO UNLOCK (one-time purchase) • Encrypt and decrypt files of any type. • Quick Look previews of .sdenc files right inside Files and Finder. • Import from Camera and Photos, and save to iCloud Drive. • Face ID / Touch ID lock and configurable autolock. • Run encrypt and decrypt from Shortcuts, Siri, and Spotlight — or with a long-press in Files. STRONGER ENCRYPTION • New files use AES-256-GCM with PBKDF2-HMAC-SHA256 key strengthening (600,000 iterations), a random salt and nonce per file, and an authentication tag that detects tampering. • Your existing encrypted files still open — Secret Delivery detects the format automatically. Need to send a file to someone on an older version? Turn on Legacy Mode for the session, or upgrade old files in place. PRIVATE BY DESIGN • Everything happens on-device. We collect nothing, and there is no analytics SDK. • The app blurs its contents in the app switcher and wipes temporary decrypted files when it moves to the background. EXISTING CUSTOMERS Already bought Secret Delivery? Thank you — everything stays unlocked at no extra cost. Just open the app on your Apple ID and Pro is restored automatically.

About

Zero Duplicates

Reclaim iPhone storage by finding and deleting duplicate files, even those with different names. Advanced content analysis ensures accurate identification, and a privacy-first design keeps your data local. Safely organize documents, images, videos, and more.

Highlights
  • Advanced content analysis for real duplicates
  • Finds duplicates with different filenames
  • Supports documents, images, videos, audio, and downloads
  • Scans iCloud Drive and external storage
  • Privacy-first local scanning
  • Auto-select duplicates by newest/oldest
  • Preview before deleting
Read full description

Most cleaning apps on the App Store focus on the photo library. Zero Duplicates focuses on your files: the downloads, documents, PDFs, videos and audio files that pile up in the Files app and quietly fill your storage. Zero Duplicates compares files by their content, not by their names. A renamed download, an attachment saved twice, a document copied into three folders: all of them are found, even when the file names look nothing alike. MADE FOR THE FILES ON YOUR DEVICE • Scan any folder you choose: On My iPhone, iCloud Drive, external drives • Downloads from Safari, Mail and Messages • Documents: PDF, Word, Excel, Pages, Numbers, Keynote • Images, videos, audio recordings, archives and more • USB drives and SD cards (with adapter) CONTENT MATCHING File names lie. Zero Duplicates reads the actual content of every file, so duplicates are found even when they were renamed, moved or saved from different apps. AUTO-SELECT IN SECONDS Automatic selection keeps the newest or the oldest file in every duplicate group. Review, tap once, done. No scrolling through hundreds of files by hand. SEE BEFORE YOU DELETE Every duplicate can be previewed before deletion, and you choose which copy stays. At least one version of every file always remains, so losing all copies is impossible. Deletion is permanent, so nothing is removed without a clear confirmation first. PRIVATE BY DESIGN Scanning happens entirely on your device. Your files are never uploaded anywhere. HOW IT WORKS Pick a folder, scan, review what was found, delete with confidence. Three steps to a cleaner device. System files are protected automatically. Perfect for: • Anyone seeing "Storage Almost Full" warnings • People who download and share lots of files • Managing documents, media and work files on the go • Cleaning up iCloud Drive across devices TRY WITHOUT RISK Free to download • Unlimited scans • 500 MB free deletion Premium unlocks unlimited deletion and advanced features. Terms of Use: https://zeroduplicates.com/terms

Screenshots

Secret Delivery4 screens
Zero Duplicates4 screens

Verdict

The call

The clearest difference is price: Zero Duplicates at Free against Secret Delivery's $0.99. Zero Duplicates also leads on rating (4.8 vs 4.0) and update cadence (weekly vs every 8 months). On ads, in-app purchases and device support 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

CostPrice · In-app purchases · Ads · Monetization

Zero Duplicates is free to download; Secret Delivery costs $0.99 up front. Secret Delivery sells 1 one-off in-app purchase and Zero Duplicates sells 3 in-app purchases, starting at $4.99 per month. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

Zero Duplicates holds the better App Store score, 4.8 against 4.0. That said, the two scores are not equally well evidenced: Zero Duplicates has 65 ratings behind it against 4, so its average is the more settled of the two. Written reviews point the same way: 71% of Secret Delivery's written reviews are positive against 80% of Zero Duplicates's.

UpkeepUpdate frequency

Secret Delivery ships an update every 8 months, Zero Duplicates weekly. The most recent releases landed on November 1, 2026 and November 5, 2026 respectively.

Scorecard7 real differences · 3 level
Secret Delivery versus Zero Duplicates: the parameters behind the verdict, then further details
ParameterSecret DeliveryZero Duplicates
Price$0.99Free — better
Rating4.0 (4 ratings)4.8 (65 ratings) — better
Positive reviews71.4% of reviews80.0% of reviews — better
Number of ratings465 — better
Update frequencyEvery 8 monthsWeekly — better
AdsNoNo
In-app purchasesYesYes
MonetizationPaidFreemium — better
DevicesiPhone, iPad, Mac — betteriPhone, iPad
Requires iOS26.017.0 — better
Further details — not scored
Size9 MB20 MB
Age rating4+4+
DeveloperTractusChristopher Brock

Customer experience

Secret Delivery

All ratings4 ratings
Positive75.0%
Neutral0.0%
Negative25.0%
Written reviews7 reviews
Positive71.4%
Neutral0.0%
Negative28.6%

Zero Duplicates

All ratings63 ratings
Positive96.8%
Neutral3.2%
Negative0.0%
Written reviews10 reviews
Positive80.0%
Neutral10.0%
Negative10.0%

In-app purchases

1 purchases

Secret Delivery

One-time1
  • Secret Delivery Pro$0.99
3 purchases

Zero Duplicates

Subscriptions2
  • Monthly Subscription$4.991 Month
  • Yearly Subscription$7.991 Year
One-time1
  • Lifetime$14.99

Questions

Is Secret Delivery free?
Secret Delivery costs $0.99, and also offers in-app purchases.
Is Zero Duplicates free?
Zero Duplicates is free to download, with in-app purchases available.
Which has better reviews, Secret Delivery or Zero Duplicates?
Zero Duplicates is rated higher. Secret Delivery averages 4.0 out of 5 from 4 ratings, while Zero Duplicates averages 4.8 from 65 ratings.
Do Secret Delivery or Zero Duplicates have ads?
Neither Secret Delivery nor Zero Duplicates shows ads.
Which is updated more often, Secret Delivery or Zero Duplicates?
Secret Delivery ships an update every 8 months, and Zero Duplicates weekly. Most recently, Secret Delivery was updated on November 1, 2026 and Zero Duplicates on November 5, 2026.

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