Co-Star, The Pattern, CHANI, TimePassages: astrology apps compared on checkable criteria

Comparisons of astrology apps usually rank vibes. This one ranks facts, and only facts you can check yourself: App Store privacy labels, published prices, official support pages. One disclosure up front: Astraleria is our app, so we have an interest here. That is exactly why every claim below names where it comes from, and why the criteria are ones where checking beats trusting. Prices are US App Store figures as of August 2026 and can change.

What the privacy labels actually say

Apple’s privacy labels are self-declared but binding, and they differ sharply across the field.

• Co-Star declares “Data Linked to You”: contacts, identifiers, usage data. An account (phone number, Facebook or Apple ID) is part of the documented onboarding. The independent Common Sense privacy evaluation rates it “Warning”, citing third-party data use for personalized advertising.
• The Pattern declares contact info (email, name, phone number), user content, identifiers and usage data as linked to you; onboarding runs through an account.
• CHANI declares contact info and user content linked to you.
• TimePassages declares only unlinked usage and diagnostics data; charts sync through an optional cloud account.
• Time Nomad, the smaller methodical competitor, carries the strongest label in the field: “Data Not Collected”, no registration at all.

Astraleria’s position: no account, no server, no analytics; birth data never leaves the device. A birth chart requires the most sensitive personal datum there is, the exact time and place a person came into the world. Whether that belongs on someone’s server, linked to your phone number, is a question every user can answer for themselves; the labels make the arrangements visible.

Who shows their math

An astrology app computes positions. Whether you may see them, and whether the method is disclosed, varies:

• Co-Star states its positions come from NASA JPL data and discloses its house system: Porphyry by default, switchable to Placidus or Whole Sign. Raw degree display in the app: not documented.
• The Pattern names Whole Sign houses in its support pages and offers a free natal chart on its website; the app itself deliberately avoids astrological terminology, glyphs and degrees.
• CHANI works with Whole Sign houses and a traditional, rising-sign-centered approach; an engine or ephemeris disclosure is not published.
• TimePassages shows full raw data in the app (degrees, dignities, declinations); Swiss Ephemeris is documented for the desktop products.
• Time Nomad documents its ephemeris (NASA DE430), computes offline, and shows everything.

Astraleria publishes the whole pipeline: engine method, validation against Swiss Ephemeris to within one arcminute, conventions per feature, and a standing invitation to prove the numbers wrong, all on the accuracy page. We believe we are the only mainstream-design app that pairs full disclosure with raw data under every reading; if that changes, this article will be corrected.

What synastry costs

For couples and friends, the comparison feature is often the actual reason to install an astrology app. The pricing tells its own story:

• Co-Star: relationship analysis is an in-app purchase (Advanced Chart: Relationships, 8.99 dollars), and adding a person manually costs 2.99 dollars.
• The Pattern: bonds and compatibility exist in the free tier, but the connected features run through Connect+ (24.99 dollars per quarter) and custom profile slots cost extra.
• CHANI: no synastry feature.
• TimePassages: comparison charts cost 0.99 dollars each or require the Pro subscription.
• Time Nomad: synastry is a 4.99 dollar one-time purchase.

Astraleria’s first full chart comparison is free, needs no account from either person, and the web synastry calculator computes all contacts in your browser without the app entirely.

Languages

All five competitors list English as their only App Store language. Astraleria ships in 14 languages, written natively rather than machine translated. For most of the world, this is not a detail; it is whether the app speaks to you at all.

The honest summary

If you want social astrology with friends’ charts in a feed, Co-Star and The Pattern are built for that, and nothing here replaces them. If you want a working astrologer’s voice, CHANI is exactly that. TimePassages and Time Nomad are serious calculators with full data for people who already read charts.

Astraleria’s wager is that one app can be modern in design, private, precise, and multilingual at once, and that nobody should have to take any of those four claims on faith. The sources for this comparison are the apps’ own store listings and support pages; check them, and check ours.