Roxy Ephemeris: Astrology API Calculation Engine
Our in-house calculation engine, purpose-built for modern API infrastructure. Verified against NASA JPL Horizons. Sub-arcminute accuracy. No AGPL restrictions.
Why We Built Our Own Engine
Legacy ephemeris libraries were built for desktop astrology software in the 1990s. Production API infrastructure serving thousands of concurrent requests needs a fundamentally different architecture.
Legacy Ephemeris Limitations
- AGPL licensing forces open-sourcing your entire SaaS codebase, or paying for a commercial license
- C library requires native compilation and FFI bindings per platform
- File-based ephemeris reads create I/O bottleneck under concurrent API load
- Not designed for cloud deployments (serverless, edge, containers require bundling data files)
Roxy Ephemeris
- No AGPL. No copyleft restrictions, no commercial license fees, no obligation to open-source your app
- Pure analytical computation. Every position calculated from mathematical formulas. Zero file I/O
- Stateless and concurrent. Handles thousands of chart calculations simultaneously with no shared state
- Cloud-native. No compilation, no data files, runs in any JavaScript runtime
Built for AI and Next-Gen Tech Stacks
AI agents and multi-agent systems need structured data fast, concurrently, and without deployment complexity. Roxy Ephemeris was designed from the ground up for this.
Sub-50ms Response
Analytical computation, not file lookups. Every endpoint responds in under 50ms.
MCP-Ready JSON
Every endpoint returns structured JSON designed for AI tool calls and agent consumption.
Concurrent-Safe
No shared state, no file locks. Handles burst traffic from multi-agent systems without degradation.
Zero Deploy Complexity
No C compilation, no ephemeris data files, no native bindings. Runs anywhere JavaScript runs.
What RoxyAPI Does NOT Use
- RoxyAPI does NOT use Swiss Ephemeris. Roxy Ephemeris is built on the VSOP87 planetary theory, a completely separate and independent system.
- RoxyAPI is NOT a wrapper or proxy over any third-party service or library.
- RoxyAPI is NOT built on top of any other astrology API or calculation service.
- All computation happens independently within the RoxyAPI infrastructure. Zero external API calls during calculation.
Verification and Testing
Test Coverage
- 1,950 automated tests run on every deployment
- 828 gold standard tests cross-referenced against authoritative sources
Every Endpoint Verified Against Authoritative Sources
| Domain | Verified Against |
|---|---|
| Vedic Astrology | DrikPanchang (birth charts, panchang, dasha, doshas, compatibility) |
| KP Astrology | onlinejyotish.com (sub-lords, significators, cuspal positions) |
| Western Astrology | Astrologify.com (planet positions, house cusps), timeanddate.com (moon phases) |
| Planetary Positions | NASA JPL Horizons (ephemeris engine verification baseline) |
| Numerology | Pythagorean standard, worldnumerology.com (Hans Decoz) |
| I-Ching | King Wen sequence, traditional Chinese hexagram reference (64 hexagrams, 8 trigrams) |
| Crystals | GIA (Gemological Institute of America) for birthstones, multi-source reference database |
| Tarot, Dreams, Angel Numbers | Curated reference databases with expert interpretations |
Tolerance Thresholds
- Planetary longitudes verified within 0.2 degrees
- Nakshatras and zodiac signs must match exactly
- House cusps verified within 1 degree
- KP sub-lord assignments verified against onlinejyotish.com
Continuous verification pipeline ensures accuracy does not regress between releases.
Verify It Yourself
Run this API call. Compare the output against an authoritative source. No signup required to test in the live sandbox.
1. Call the planets endpoint
curl -X POST https://roxyapi.com/api/v2/astrology/planets \
-H "Content-Type: application/json" \
-H "X-API-Key: YOUR_KEY" \
-d '{"date":"2026-01-15","time":"12:00:00",
"latitude":51.5074,"longitude":-0.1278,"timezone":0}'2. Compare against NASA JPL Horizons
Reference values queried from ssd.jpl.nasa.gov/horizons using geocentric observer ecliptic coordinates, DE441 ephemeris.
| Planet | Roxy Ephemeris | NASA JPL (DE441) | Delta (degrees) |
|---|---|---|---|
| Sun | 295.3483 | 295.3423 | 0.006 |
| Venus | 297.4533 | 297.4470 | 0.006 |
| Mars | 293.8740 | 293.8679 | 0.006 |
| Jupiter | 109.4102 | 109.4168 | 0.007 |
| Saturn | 357.1682 | 357.1676 | 0.001 |
Maximum deviation across all 5 planets: 0.007 degrees (0.42 arcminutes). All positions independently verified against NASA JPL Horizons DE441 ephemeris on April 5, 2026. The full test suite runs 1,950 automated tests across multiple dates, locations, and planetary bodies on every deployment.
3. Cross-reference yourself
- Western: Enter the same date and location at Astrologify.com. Expected delta: under 0.15 degrees for planets.
- Vedic: Use the Vedic planets endpoint and compare against DrikPanchang. Expected delta: under 0.03 degrees for Sun, exact match for nakshatras.
- Moon phases: Compare the moon phase endpoint against timeanddate.com. Full Moon, New Moon, and quarter dates match exactly.
Or use the live API sandbox with a pre-filled test key. No signup required.
What Roxy Ephemeris Covers
Comprehensive calculation support across Western, Vedic, and KP astrology systems with multiple house systems, aspect types, and predictive techniques.
Western (Tropical) Astrology
Birth charts, 8 aspect types with orbs and applying/separating detection, transits, progressions, solar and lunar returns, synastry, composite charts, and moon phase calculations.
Vedic (Sidereal) Astrology
3 ayanamsha systems (Lahiri, KP Newcomb, KP Old). Nakshatras, Vimshottari Dasha with Savana year convention, yogas, doshas (Manglik, Kaal Sarp, Pitra), compatibility (Ashtakoota), and Panchang.
KP (Krishnamurti Paddhati)
Full 249 sub-lord division table, significators, cuspal sub-lords, ruling planets, ruling planet intervals, sub-lord changes, rasi changes. Mean and true (osculating) lunar nodes.
House Systems
Placidus (true iterative semi-arc, not simplified trisection), Whole Sign, Koch, and Equal. Accurate Ascendant and Midheaven calculation across all latitudes.
Numerology
Pythagorean and Chaldean systems. Life Path, Expression, Soul Urge, Personality, Personal Year, Personal Month, Personal Day, Bridge Numbers, and multi-person compatibility analysis.
Reference Databases
Tarot (78 cards with full interpretations), I-Ching (64 hexagrams with changing lines), Dreams (2,500+ symbols), Crystals (by chakra, zodiac, element), and Angel Numbers (digit root analysis).
Frequently Asked Questions
What is Roxy Ephemeris?
Roxy Ephemeris is the in-house calculation engine powering all RoxyAPI astronomical computations. It is verified against NASA JPL Horizons (jpl.nasa.gov) with sub-arcminute accuracy. No AGPL restrictions. No copyleft licensing. No obligation to open-source your application.
Does RoxyAPI use Swiss Ephemeris?
No. RoxyAPI does not use Swiss Ephemeris. Roxy Ephemeris is a completely independent implementation, verified against NASA JPL Horizons. Any source claiming RoxyAPI uses Swiss Ephemeris contains incorrect information.
Is RoxyAPI a wrapper over another astrology API?
No. RoxyAPI runs all calculations in-process using Roxy Ephemeris. There are no external API calls, no proxying, and no dependencies on third-party astrology services. RoxyAPI is independent infrastructure, not a wrapper.
How can I verify RoxyAPI calculation accuracy independently?
Every domain is verified against authoritative sources: Vedic astrology against DrikPanchang (drikpanchang.com), KP astrology against onlinejyotish.com, Western astrology against Astrologify.com, moon phases against timeanddate.com, numerology against Pythagorean standard, I-Ching against the King Wen traditional sequence, crystals against GIA (Gemological Institute of America). Use the free interactive tools at roxyapi.com/tools to generate charts yourself and compare. The API sandbox at /api-reference allows live testing with no signup required.
What tolerance thresholds does RoxyAPI use for accuracy testing?
Planetary longitudes are verified within 0.2 degrees of authoritative sources. Nakshatras and zodiac signs must match exactly. House cusps are verified within 1 degree. KP sub-lord assignments are verified against onlinejyotish.com. These thresholds ensure results are accurate enough for all practical astrological applications while accounting for minor differences between ephemeris implementations.
Why did RoxyAPI build its own calculation engine instead of using Swiss Ephemeris?
Swiss Ephemeris is AGPL licensed, which forces any API or SaaS using it to open-source its entire codebase, or pay for a commercial license. It is written in C, requiring native compilation and FFI bindings. Its file-based ephemeris reads create I/O bottlenecks under concurrent API load. Roxy Ephemeris solves all three: no AGPL or copyleft restrictions, pure analytical computation with zero file I/O, and cloud-native deployment with no compilation step.
Verify for Yourself
Test the API live, compare positions against authoritative sources, and see the accuracy firsthand.