Comparison

Message Viewer Pro vs OnePreview

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

Head to head
About

Message Viewer Pro

Easily view EML and MSG email files, including attachments, directly on your iOS or macOS device. Share or print attachments, or compose new emails using the content of your saved messages.

Highlights
  • View EML and MSG files
  • Access attachments
  • Share attachments
  • Print attachments
  • Compose new emails from viewed messages
Features
Read full description

View both EML and MSG (Outlook) files on your iOS/macOS device, including attachments within them. These are usually emails saved in the EML or MSG format. Tap on an EML or MSG file in another app, "Open In..." and select Message Viewer to view your saved email. You may tap "open a sample EML" to see an example email open up. Attachments may be shared with other apps or printed. Tap the compose icon to open your EML/MSG as a new Mail message.

About

OnePreview

Features
Read full description

Open Markdown and developer files in OnePreview on iPhone and iPad. OnePreview renders GitHub-style Markdown, MDX, TextBundle and TextPack packages, JSON, JSONL, YAML, XML, CSV, TSV, TOML, ENV, SQLite databases, source code, plain text, logs, and ZIP and TAR.GZ archives. In Files, long-press a supported document, choose Open With, then select OnePreview. A normal tap may use Apple's built-in preview for common file types. Inside OnePreview, switch between rendered Markdown and source, view Mermaid diagrams and KaTeX math with bundled assets, inspect structured data and SQLite schemas, and check archive contents before extracting. Built for developer workflows, AI-generated files, documentation review, and everyday file browsing. Processing is fast, local-first, and does not require an account.

Screenshots

Message Viewer Pro2 screens
OnePreview4 screens

Verdict

The call

The clearest difference is price: OnePreview at Free against Message Viewer Pro's $3.99. OnePreview also leads on update cadence (every 2 weeks vs monthly). On ads, in-app purchases, device support and iOS requirement 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

OnePreview is free to download; Message Viewer Pro costs $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

Message Viewer Pro ships an update monthly, OnePreview every 2 weeks. The most recent releases landed on September 17, 2026 and September 11, 2026 respectively.

Scorecard2 real differences · 7 level
Message Viewer Pro versus OnePreview: the parameters behind the verdict, then further details
ParameterMessage Viewer ProOnePreview
Price$3.99Free — better
Rating5.0 (1 ratings) — better—
Number of ratings1 — better—
Update frequencyMonthlyEvery 2 weeks — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaid—
DevicesiPhone, iPadiPhone, iPad, Mac — better
Requires iOS16.6 — better17.0
Further details — not scored
Size9 MB8 MB
Age rating4+4+
DeveloperMatrix Logic Corporation培克 罗

In-app purchases

None

Message Viewer Pro

No in-app purchases

None

OnePreview

No in-app purchases

Questions

Is Message Viewer Pro free?
Message Viewer Pro costs $3.99, with no in-app purchases.
Is OnePreview free?
OnePreview is free to download, with no in-app purchases.
Do Message Viewer Pro or OnePreview have ads?
Neither Message Viewer Pro nor OnePreview shows ads.
Which is updated more often, Message Viewer Pro or OnePreview?
Message Viewer Pro ships an update monthly, and OnePreview every 2 weeks. Most recently, Message Viewer Pro was updated on September 17, 2026 and OnePreview on September 11, 2026.

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