Daily astrology readings for couples

The idea

Astrology apps are built for one person, but the people who love them are constantly reading horoscopes about their relationships — compatibility content is the highest-engagement category in the entire niche. Co-Star and The Pattern bolt compatibility on as a feature; nobody has built the daily ritual around the couple as the unit. A shared reading both partners see, with a prompt they answer together, is a different product, not a feature.

Project A proves AI-generated astrology converts to paid subscriptions right now, at scale. The wedge is structural: the two-person mechanic changes the content, the notification (both phones buzz with the same reading), and the reason to open the app. It also builds in distribution — every paying user recruits a second retained user by design, and the incumbents would have to redesign their single-player architecture to follow. Real ephemeris math under LLM prose keeps content fresh at near-zero marginal cost and credible to fans who spot fake astrology immediately.

Who pays

Realistically one partner — usually the astrology-invested one, skewing women 20-35 — pays $8-12 a month or ~$50 a year covering both accounts. The purchase is framed as a relationship ritual, which supports annual pricing. Distribution: astrology TikTok and Instagram (couple-reading content is inherently shareable), ASO on couples astrology and synastry keywords, and the invite loop itself — every signup tries to pull in a partner who wasn’t searching for the app.

MVP scope

• Birth-data onboarding with server-side natal and synastry chart computation from a real ephemeris
• Partner invite link, with solo mode where one user enters both charts
• Daily generated couple reading, per-partner line, and conversation prompt, delivered by synchronized push
• Two-tap mood check-in with shared timeline
• RevenueCat paywall after a 7-day streak, monthly and annual tiers
• Skip for v1: Android-second is fine but pick one platform, chat/AI astrologer Q&A, tarot, friend compatibility, widgets, web version

Build Synastry, a daily astrology app for couples. Stack: React Native with Expo, a Swiss Ephemeris wrapper (swisseph) running server-side for chart math, Claude API for reading generation, RevenueCat for subscriptions.

Core flow: 1) User enters their birth date, time, and place; the server computes their natal chart. 2) They invite their partner via share link; partner enters their own birth data (or the user enters it for them — support both, many partners won't install). 3) The server computes the synastry chart — real inter-chart aspects, not sun-sign lookup — plus today's transits against both charts. 4) Each morning a job generates the shared daily reading: Claude receives the computed aspects and transits as structured data and writes a 150-word couple reading, one line per partner, and a conversation prompt tied to the day's dominant aspect. 5) Both partners get the same push notification; opening shows the reading plus a two-tap mood check-in. When both check in, each sees the other's mood on a shared timeline.

Screens: onboarding + birth data entry, partner invite, today (reading, prompt, check-in), relationship chart explainer, mood timeline, settings, paywall.

Non-obvious details: never let the LLM do astronomy — pass it computed aspects with orbs and let it only write prose, or fans will catch errors instantly. Cache one reading per couple per day; cost stays near zero.

Pricing via RevenueCat: $9.99/mo or $49.99/yr covering both partners, paywalled after a 7-day free reading streak.