OpEvol vs SkyLetter
Price, ratings, monetisation and update history for both apps, side by side β with what reviewers say about each.
OpEvol
Experience a dynamic, ever-changing display of psychedelic visuals inspired by 1960s Op Art. This app creates animated fields of geometric colors and contrasts for passive viewing or interactive play.
- Animated geometric patterns
- Op Art inspired visuals
- Psychedelic color displays
- Interactive visual play
- Air Display compatibility
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Inspired by Op Art of the 1960s, OpEvol takes the geometric play of colors and contrasts and animates them into a moving field of ever-changing, optical, kinetic abstraction. It's for staring at. It's for sending to Air Display. Or an external monitor. Or a projector. It's something mesmerizing to design and watch evolve, or just leave on in the background as art. OpEvol Pro is an auto-renewing annual subscription (price shown in the app). Payment is charged to your Apple ID at purchase, and it renews automatically unless canceled at least 24 hours before the end of the period. Manage or cancel anytime in your Apple ID settings. Privacy Policy: https://muddlegeist.com/opevol/privacy Terms of Use (EULA): https://muddlegeist.com/opevol/terms
SkyLetter
Create personalized messages drawn in the sky with airplane contrails. Share your creations as videos or photos on social media, perfect for sending unique greetings or declarations.
- Draw messages in the sky with contrails
- Share creations as video or photo
- Personalize messages for friends
- Unique social media content
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γDeliver your message in the cloudγ "SkyLetter" is an application that draws a message in the sky with contrail. Look up at the sky after entering the message. The airplane which received your message there draws a message with a trail of contrail. Why don't you draw in the sky the names of you, your friends, and the messages you want to convey? You can share it as a video or photo on social media. Let's take a photo that is drawn message and send it to many people. γRecommended environmentγ Support for iOS12.0 or later / iPhone 6S later. If your device is under iOS 12.0, please update and install.
Screenshots
Verdict
The clearest difference is in-app purchases: SkyLetter at none against OpEvol's 1. SkyLetter also leads on update cadence (fortnightly vs every 22 months) and iOS requirement (12.0 vs 26.0). On price, review sentiment, ads and device support there is nothing between them.
Scored on Price Β· Rating Β· Positive reviews Β· Number of ratings Β· Update frequency Β· Ads Β· In-app purchases Β· Monetization Β· Best chart rank Β· Devices Β· Requires iOS
Both are free to download. OpEvol sells 1 in-app purchase, starting at $6.99 per year. SkyLetter asks for nothing beyond the download.
OpEvol ships an update every 22 months, SkyLetter fortnightly. The most recent releases landed on September 30, 2026 and October 6, 2026 respectively.
| Parameter | OpEvol | SkyLetter |
|---|---|---|
| Price | Free | Free |
| Positive reviews | 27.3% of reviews β better | 25.0% of reviews |
| Update frequency | Every 22 months | Fortnightly β better |
| Ads | No | No |
| In-app purchases | Yes | No β better |
| Monetization | Paid | Free β better |
| Devices | iPhone, iPad, Apple TV β better | iPhone, iPod |
| Requires iOS | 26.0 | 12.0 β better |
| Further details β not scored | ||
| Size | 3 MB | 45 MB |
| Age rating | 4+ | 4+ |
| Developer | Muddlegeist | Kiyotaka Watanabe |
Customer experience
OpEvol
SkyLetter
In-app purchases
OpEvol
- OpEvol Annual Subscription$6.991 Year
SkyLetter
No in-app purchases
