Comparison

Stella vs Piday

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

Head to head
About

Stella

Practice Spanish through AI-powered conversations and interactive lessons. Get instant feedback on pronunciation and grammar to build real-world speaking confidence. Personalized learning paths adapt to your progress, from beginner to advanced.

Highlights
  • AI conversation practice
  • Pronunciation and speaking training
  • Grammar and vocabulary lessons
  • Listening and reading comprehension
  • Interactive quizzes
  • Personalized learning paths
Features
Read full description

Stella AI – Learn Spanish with Your Personal AI Tutor Learning Spanish should feel like having real conversations—not memorizing endless vocabulary lists. Stella AI is a personalized Spanish learning app that helps you learn Spanish through AI-powered conversations, interactive lessons, and instant feedback. Whether you're taking your first lesson or building on what you already know, Stella helps you speak Spanish with greater confidence through personalized practice that fits your level and goals. Learn Spanish with AI Meet your personal AI Spanish tutor and practice whenever inspiration strikes. Have natural conversations, receive real-time feedback, and improve your speaking skills with lessons designed around everyday communication. If you're looking for a smarter way to learn how to speak Spanish, Stella adapts every lesson to your progress. Build Real Conversation Skills Go beyond memorization and start using Spanish in real-life situations. Practice conversations for travel, work, daily life, and more while improving your pronunciation, listening, and speaking naturally. Every session is designed to help you feel more comfortable when you talk in Spanish. Improve Every Essential Language Skill Develop all the skills you need to communicate confidently: • AI conversation practice • Speaking and pronunciation training • Grammar and vocabulary lessons • Listening and reading comprehension • Interactive quizzes with instant feedback • Spanish lessons for beginners to advanced learners Whether you're learning Spanish for beginners or advancing toward fluency, Stella creates a learning path that's personalized for you. Learn at Your Own Pace Short, focused lessons make it easy to practice every day. Build consistent learning habits, track your progress, and enjoy a more engaging way to learn a language—one conversation at a time. Why Learners Choose Stella - Personalized AI tutor - Real conversations instead of rote memorization - Instant pronunciation feedback - Adaptive lessons that match your level - Practical Spanish for everyday situations - Fun, interactive learning experience Whether you're preparing for travel, communicating with friends and family, exploring new career opportunities, or simply enjoying the process of learning a new language, Stella helps you build the confidence to use Spanish in everyday life. Start learning today with Stella AI and discover a more natural way to learn Spanish, practice real conversations, and become a confident Spanish speaker. --- Subscription Service By confirming your purchase, your iTunes account will be charged. Subscriptions automatically renew unless auto-renew is turned off at least 24 hours before the end of the current period. You can manage or cancel your subscriptions at any time through your Apple ID account settings. Even after cancellation, you can continue using premium features until the end of the current subscription period. After the subscription ends, you will no longer have access to these features. Privacy Policy: https://stella-ai-ddabb.web.app/privacy-policy.html Terms of Service: https://stella-ai-ddabb.web.app/terms-of-service.html Support Information: https://stellalearn.ai/

About

Piday

This app reveals the precise location of any date within the first five billion digits of pi. Search for significant dates like birthdays or anniversaries and explore their placement in pi's infinite sequence. It supports various date formats and allows you to save and share your discoveries.

Highlights
  • Find today's date in pi
  • Search for any date in pi
  • See exact position of dates
  • Compare multiple date formats
  • Explore calendar heat map
  • Save favorite dates
  • Share discoveries as cards
Features
Read full description

PiDay is the nerdiest calendar app ever made. Every day, PiDay opens to today and shows you exactly where that date appears in the first five billion decimal digits of pi. Search for your birthday, an anniversary, or any date you care about, then see where it lives in infinity. PiDay searches multiple date formats and highlights the best match, so you can explore your date from different calendar conventions and compare where each one appears. Features: Find today’s date in pi instantly Search birthdays, anniversaries, and any other date See the exact position where a date appears Compare multiple date formats Explore a calendar heat map of how early dates appear Save favorite dates Share your discoveries as cards Personalize the app with multiple themes Works on iPhone, iPad, and Mac PiDay keeps things simple: No accounts No ads No tracking A decade worth of bundled dates, or search any string using a live lookup service for dates outside the bundled range. If you’ve ever wondered whether your birthday is hiding in pi, this is the app for you.

Screenshots

Stella4 screens
Piday4 screens

Verdict

The call

The clearest difference is review sentiment: Piday at 100% against Stella's 18%. Piday also leads on rating (5.0 vs 4.5) and in-app purchases (none vs 10). Stella's advantage is ratings volume (3.6K vs 1) and iOS requirement (15.0 vs 17.0). On price, update cadence and ads 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

Both are free to download. Stella sells 10 in-app purchases, starting at $5.99 per 7 days. Piday asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Piday holds the better App Store score, 5.0 against 4.5. That said, the two scores are not equally well evidenced: Stella has 3.6K ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 18% of Stella's written reviews are positive against 100% of Piday's.

UpkeepUpdate frequency

Stella ships an update every 8 days, Piday every 2 weeks. The most recent releases landed on November 8, 2026 and November 5, 2026 respectively.

Scorecard7 real differences · 3 level
Stella versus Piday: the parameters behind the verdict, then further details
ParameterStellaPiday
PriceFreeFree
Rating4.5 (3.6K ratings)5.0 (1 ratings) — better
Positive reviews17.6% of reviews100.0% of reviews — better
Number of ratings3.6K — better1
Update frequencyEvery 8 days — betterEvery 2 weeks
AdsNoNo
In-app purchasesYesNo — better
MonetizationFree with in-app purchasesFree — better
DevicesiPhone, iPodiPhone, iPad, Mac, Apple Watch — better
Requires iOS15.0 — better17.0
Further details — not scored
Size225 MB49 MB
Age rating4+4+
DeveloperHONG KONG BETENSH LIMITEDErik Veland

Customer experience

Stella

All ratings3,600 ratings
Positive86.4%
Neutral6.1%
Negative7.5%
Written reviews153 reviews
Positive17.6%
Neutral7.8%
Negative74.5%

Piday

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Bugs and requests

Stella

Reported bugs

3 issues
  • App freezing and crashing during lessons
  • Incorrect answers marked as correct
  • Inability to progress through lessons

Requested features

4 requests
  • More advanced lessons and content
  • Improved speech recognition and feedback
  • Addition of songs and music-based learning
  • Better customer support and responsiveness

Piday

Not enough reviews yet to summarise bugs or requests.

In-app purchases

10 purchases

Stella

Subscriptions10
  • Stella AI PRO: Weekly$5.997 Days
  • Stella AI PRO: Weekly3 Days trial$7.997 Days
  • Stella AI PRO: Weekly Plan$7.997 Days
Show 7 more
  • Stella AI PRO: Month$19.991 Month
  • Free Trial Plan3 Days trial$29.991 Year
  • Stella AI PRO: Annual$29.991 Year
  • Stella AI PRO: Annual$39.991 Year
  • Stella AI PRO: Annual3 Days trial$49.991 Year
  • Stella AI PRO: Annual$49.991 Year
  • Stella AI PRO: Annual$59.991 Year
None

Piday

No in-app purchases

Questions

Is Stella free?
Stella is free to download, with in-app purchases available.
Is Piday free?
Piday is free to download, with no in-app purchases.
Which has better reviews, Stella or Piday?
Piday is rated higher. Stella averages 4.5 out of 5 from 3.6K ratings, while Piday averages 5.0 from 1 ratings.
Do Stella or Piday have ads?
Neither Stella nor Piday shows ads.
Which is updated more often, Stella or Piday?
Stella ships an update every 8 days, and Piday every 2 weeks. Most recently, Stella was updated on November 8, 2026 and Piday on November 5, 2026.

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