Astrology Apps

Building an astrology app like Co-Star, Sanctuary, The Pattern, Chani, or Costar Compat? AstroWay API replaces the need to license Solar Fire ($495) or build your own ephemeris: 761 endpoints (natal charts, synastry, transits, Human Design, AI interpretations), OpenAPI 3.1 plus published TypeScript, Python and PHP SDKs, Swiss Ephemeris accuracy - the same engine that powers Astrodienst and Kepler.

Typical architecture

User (browser / mobile)
     ↓
Your backend (Node.js / Python / PHP)
     ↓ HTTPS + X-Api-Key
api.astroway.info/v1/*
     ↓
JSON response → render in your UI

Caution

Never put the API key in frontend code. AstroWay API calls must go through your backend or serverless functions (Next.js API routes, Vercel functions, AWS Lambda).

Key endpoints for an astrology app

MVP (minimum viable product)

Endpoint	Credits	Purpose
/v1/chart	20	Natal chart calculation
/v1/synastry	50	Compatibility between two people
/v1/horoscope/daily	50	Daily horoscope

Three endpoints and you have a working product with natal charts, compatibility, and daily content.

Expanded product

Endpoint	Credits	Purpose
/v1/transits	50	Current transits on natal chart
/v1/solar-return	50	Solar return (annual chart)
/v1/progressions	50	Secondary progressions
/v1/interpret/natal	100	AI-interpreted natal chart
/v1/transit-calendar	100	Transit event calendar
/v1/human-design	50	HD chart

Premium features

Endpoint	Credits	Purpose
/v1/rectification	500	Birth time correction
/v1/acg	50	Astrocartography (where to live)
/v1/forecast-calendar	100	Annual forecast heatmap
/v1/group-synastry	100	Group compatibility

Budget estimation

Scenario: 100 DAU (daily active users)

Assuming an average user performs 3 actions per day:

Action	Endpoint	Credits	Requests/day	Credits/day
View chart	/v1/chart	20	100	2,000
Daily horoscope	/v1/horoscope/daily	50	100	5,000
Compatibility	/v1/synastry	50	30	1,500
Total			230	8,500/day

~255,000 credits/month (8,500 × 30) → Pro ($59/mo, 800,000 credits) with room to spare, or Starter ($19/mo, 200,000) plus ~$30 of overage for the extra 55K ($5 per 10,000 over quota). Caching the daily horoscope (one text per sign, not per user) takes 4,850 credits a day off this bill and puts the scenario back inside Starter.

Scenario: MVP with 20 DAU

Action	Credits/day
20 charts	400
20 horoscopes	1,000
5 synastries	250
Total	1,650/day

~49,500 credits/month - Indie ($5/mo, 50,000 credits) covers 99% of that, which is no headroom at all: the first bump in traffic hits overage or Starter. With horoscopes cached (12 calls a day instead of 20) it comes to ~35,000 and the headroom appears.

Tips

• Cache natal charts: input is immutable (birth date doesn’t change), so you can cache results forever in your DB
• Cache horoscopes daily: daily horoscope is the same for everyone with the same sun sign, generate once and serve
• Sandbox keys (aw_test_*): for development, don’t consume credits
• Typed clients: install @astroway/sdk, astroway or astroway/sdk; for another language, generate one from /v1/openapi.json with openapi-typescript or openapi-python-client

Quick start → First request in 5 minutes

Birth Chart API Details on natal chart endpoints

Pricing From Free to Enterprise