Co-Star vs CHANI: what is the difference?

Co-Star says its readings come from human astrologers who "collaborate with AI technology," and it is listed as free with in-app purchases. CHANI says its content is "written by astrologers, not ai," includes a journal with reflection prompts, and lists $11.99 a month on the US App Store. We compare what each source says about readings, journaling, zodiac and price. Mystogian makes a different astrology app, so neither of these is ours.

How do Co-Star and CHANI compare side by side?

Everything below comes from each app's own listing or page, seen on 2026-10-25. "Not checked" means we did not confirm it from those pages on that date. It does not mean the app lacks it.

Who writes the readings in each app?

Co-Star says its interpretations come from real human astrologers who "collaborate with AI technology." So people and AI both take part. (App Store, seen 2026-10-25)

CHANI says its content is "written by astrologers, not ai." It also offers "a new, personalized astrology reading from Chani Nicholas each week." (CHANI, seen 2026-10-25)

If you want content written only by people, CHANI's own words fit that. If you are fine with AI taking part, Co-Star says plainly that it does.

Our page on astrology apps without AI explains a related point. Who writes a reading and who calculates the chart are two separate questions.

Does either app have a journal?

CHANI says it has "a live journal — complete with personalized reflection prompts." (CHANI, seen 2026-10-25)

Co-Star: we did not check its listing for a journal on 2026-10-25, so we make no claim either way.

If a journal is the main thing you want, our page comparing astrology journal apps covers more of them.

How does each app describe its chart?

Co-Star says it uses "NASA data and biting truth." Its App Store page also says it uses "NASA data to chart the exact location of the stars in real-time." (App Store, seen 2026-10-25)

CHANI: we did not check how it describes its chart calculation for this page.

Neither App Store description mentions Vedic or sidereal astrology. That does not prove either app lacks it. It only means the listing does not say. (Co-Star, CHANI, seen 2026-10-25)

If your chart looks different in two apps, the zodiac setting is a common reason. Our page on why astrology apps give different results walks through the others.

Which phones do they run on?

Co-Star is on the App Store, where it requires iOS 18.0 or later. It is also on Google Play. (App Store, Google Play, seen 2026-10-25)

CHANI is on the US App Store. (App Store, seen 2026-10-25) We did not check its Android listing for this page.

Check the minimum iOS version before you download. An older iPhone may not meet it.

What does each app cost?

Co-Star is listed as "Free · In-App Purchases" on the US App Store. (App Store, seen 2026-10-25)

CHANI lists a monthly subscription at $11.99 on the US App Store. We did not confirm the annual price, so we leave it out. (App Store, seen 2026-10-25)

Prices differ by country and change over time. Check the store in your own region before you pay.

Which one fits what you want?

• Content written only by astrologers, with a weekly reading and a journal: CHANI says it offers all three.
• A free download, with readings where human astrologers work with AI: Co-Star says both.
• An Android phone: Co-Star's Google Play listing is confirmed. Check CHANI's yourself.
• Readings from human experts: Sanctuary says its readers are "real experts—not algorithms!" (App Store, seen 2026-10-25)
• A Vedic (sidereal) chart: neither listing mentions it. Astrocot's listing says you can "toggle between Tropical and Sidereal systems." We did not confirm Vedic support. (App Store, seen 2026-10-25)

Whichever you pick, check its chart against a free calculator such as Astro.com, with the same settings.

Related: Apps Like Co-Star: A Fact-Only Feature Table

Where does Mystogian fit?

Mystogian is a third option with a different focus. It reads your birth chart against your own journal and the decisions you log. When you log a decision, it follows up two weeks later and again three months later, if notifications are on.

It uses AI for readings, and we say so plainly. The chart itself is calculated by astronomy code on our server. The AI never calculates placements. You can see and delete what it remembers, and you can switch journal analysis off.

It has Western (tropical) and Vedic (sidereal) charts, kept separate, and relationship charts for people you add. There is a free plan, and Basic and Pro are paid. It runs on iPhone and Android and is in beta.

If you want readings written by astrologers rather than AI, CHANI says its content fits that preference.

Related: How Do You Use Astrology for Journaling and Decisions? · Join the beta

FAQ

Is Co-Star or CHANI free?

Co-Star is listed as free with in-app purchases. CHANI lists a monthly subscription at $11.99 on the US App Store.

Does Co-Star use AI?

Its App Store listing says its human astrologers "collaborate with AI technology."

Does CHANI use AI?

CHANI says its content is "written by astrologers, not ai."

Can I use both?

Yes. They are separate apps. If they show different signs for you, compare the zodiac and birth time each one uses.

Sources

All seen 2026-10-25.

• Co-Star, App Store listing: https://apps.apple.com/us/app/co-star-personalized-astrology/id1264782561
• Co-Star, Google Play listing: https://play.google.com/store/apps/details?id=com.costarastrology
• CHANI app page: https://www.chani.com/app
• CHANI, App Store listing: https://apps.apple.com/app/id1532791252
• Sanctuary, App Store listing: https://apps.apple.com/app/id1417411962
• Astrocot, App Store listing: https://apps.apple.com/us/app/astrocot/id6749895293
• Astro.com free horoscopes: https://www.astro.com/horoscope
• Mystogian: https://mystogian.com/