Comparison

smark lock vs PDF Compressor

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

Head to head
About

smark lock

Features
Read full description

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About

PDF Compressor

Features
Read full description

PDF Compressor & Photo Optimizer โ€” Everything on your iPhone, nothing in the cloud. Shrink PDFs and photos by up to 95% while you blink eyes. No internet required. No uploads. Your files never leave your device. --------------------------------- WHAT YOU CAN DO --------------------------------- COMPRESS PDF Reduce PDF file size with adjustable quality levels. Perfect for email attachments, web uploads, and freeing up storage. COMPRESS PHOTOS Shrink JPEG, PNG and HEIC images while keeping them sharp and shareable. SELECT & SPLIT PAGES Pick only the pages you need from any PDF using a visual thumbnail grid. MERGE & JOIN PDFs Combine multiple PDFs or images into a single document in seconds. PASSWORD LOCK & UNLOCK Protect sensitive PDFs with a password or remove password from encrypted files โ€” all on-device, no cloud key storage. RECENT FILES Instantly access and re-share your recently compressed or edited files. ADD SIGNATURE Append signature to your PDFs and share them instantly ----------------------------------------- WHY CHOOSE PDF COMPRESSOR ----------------------------------------- 100% on-device - your documents never leave your iPhone or iPad No account, no subscription required to get started Works offline - compress on a plane, in a meeting, anywhere Supports Files app - open and save directly from iCloud, Dropbox and more iPad & Mac (Apple Silicon) ready Perfect for students, professionals, lawyers, and anyone who handles PDFs regularly.

Screenshots

smark lock3 screens
PDF Compressor4 screens

Verdict

The call

The clearest difference is in-app purchases: smark lock at none against PDF Compressor's 3. smark lock also leads on ads (none vs shown) and iOS requirement (13.0 vs 16.2). PDF Compressor's advantage is update cadence (every 3 weeks vs every 4 months). On price and device support there is nothing between them.

Scored on Price ยท Rating ยท Positive reviews ยท Number of ratings ยท Update frequency ยท Ads ยท In-app purchases ยท Monetization ยท Best chart rank ยท Devices ยท Requires iOS

CostPrice ยท In-app purchases ยท Ads ยท Monetization

Both are free to download. PDF Compressor sells 3 in-app purchases, starting at $2.99 per month. smark lock asks for nothing beyond the download.

UpkeepUpdate frequency

smark lock ships an update every 4 months, PDF Compressor every 3 weeks. Both last shipped on September 9, 2026.

Scorecard4 real differences ยท 2 level
smark lock versus PDF Compressor: the parameters behind the verdict, then further details
Parametersmark lockPDF Compressor
PriceFreeFree
Update frequencyEvery 4 monthsEvery 3 weeks โ€” better
AdsNo โ€” betterYes
In-app purchasesNo โ€” betterYes
DevicesiPhone, iPodiPhone, iPad
Requires iOS13.0 โ€” better16.2
Further details โ€” not scored
Size40 MB31 MB
Age rating17+4+
Developer้œ‡ ็Ž‹Swetha MB

In-app purchases

None

smark lock

No in-app purchases

3 purchases

PDF Compressor

Subscriptions3
  • Unlock All Photo PDF functionality$2.991 Month
  • Unlock All Photo PDF functionality$9.996 Months
  • Unlock All Photo PDF functionality$14.991 Year

Questions

Is smark lock free?
smark lock is free to download, with no in-app purchases.
Is PDF Compressor free?
PDF Compressor is free to download, with in-app purchases available.
Do smark lock or PDF Compressor have ads?
PDF Compressor shows ads; smark lock does not.
Which is updated more often, smark lock or PDF Compressor?
smark lock ships an update every 4 months, and PDF Compressor every 3 weeks. Most recently, smark lock was updated on September 9, 2026 and PDF Compressor on September 9, 2026.

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