kerykeion
A Python library for astrological calculations, including natal charts, houses, planetary aspects, and SVG chart generation.
Decision gist · record as of 2026-08-14
Yes, if you are building an open-source or AGPL-compatible astrology application and want precise, programmable chart generation. The library is actively maintained, has low install friction, and integrates cleanly with modern Python stacks. No if your project is proprietary or closed-source—use the hosted API instead. No if you need only simple zodiac sign lookups; this is a full ephemeris and rendering system.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.10 or higher.
- pyswisseph may require a C compiler on some systems; pre-built wheels are available for common platforms.
- Low install friction with a pure-Python wheel distribution.
License · maintenance · safety
AGPL-3.0 (copyleft) — Licensed under AGPL-3.0 (copyleft). Any application that imports and uses kerykeion directly must also be AGPL-3.0 or compatible; proprietary or closed-source projects should use the hosted Astrologer API instead to avoid copyleft obligations.
last release 2026-05-25 (81 days) · last repo commit 2026-08-14 · 686 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 133,564 downloads/mo, #11,504 on PyPI
Alternatives
Verify before relying
from kerykeion import AstrologicalSubjectFactory
from kerykeion.chart_data_factory import ChartDataFactory
from kerykeion.charts.chart_drawer import ChartDrawer
subject = AstrologicalSubjectFactory.from_birth_data(
name="Example", year=1990, month=7, day=15,
hour=10, minute=30, lng=12.4964, lat=41.9028,
tz_str="Europe/Rome", online=False
)
chart_data = ChartDataFactory.create_natal_chart_data(subject)
ChartDrawer(chart_data=chart_data).save_svg(output_path=".", filename="natal")- Precision claims for astrological calculations—what reference ephemeris or algorithm standard is used
- Performance characteristics for large-scale batch chart generation or API workloads
- Completeness of house system and ayanamsa (sidereal mode) implementations relative to standard astrological practice
What it is and what it does
Kerykeion is a Python library for computing astrological data and rendering charts. It wraps Swiss Ephemeris calculations (via pyswisseph) to derive planetary positions, house cusps, and aspects, then uses SVG rendering to visualize birth charts, synastry (relationship) charts, transits, composites, and returns. The library is data-driven: it exposes astrological objects (planets, houses, aspects) as structured Pydantic models, making calculations programmable and suitable for integration with APIs and AI applications.
The package supports both online and offline modes—online uses GeoNames to resolve city coordinates, while offline requires explicit longitude, latitude, and timezone. It offers customization of planets, house systems, ayanamsa modes, and chart styling. The description emphasizes a hosted API alternative for commercial or closed-source projects to sidestep AGPL copyleft concerns.
Use it for
- Generate natal charts as SVG for astrology websites or mobile apps without server setup
- Compute synastry and composite charts to analyze relationship compatibility programmatically
- Retrieve planetary positions and aspects as JSON for integration with LLM or AI analysis workflows
- Build batch reports of transit forecasts or lunar return charts for multiple birth dates
- Embed astrological calculations in a closed-source SaaS via the hosted Astrologer API
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, if you are building an open-source or AGPL-compatible astrology application and want precise, programmable chart generation.
The library is actively maintained, has low install friction, and integrates cleanly with modern Python stacks. No if your project is proprietary or closed-source—use the hosted API instead. No if you need only simple zodiac sign lookups; this is a full ephemeris and rendering system.
Install
kerykeion on PyPI
Before you install
Low install friction with a pure-Python wheel distribution. Active maintenance with a recent release and 686 GitHub stars. Eight runtime dependencies are all well-established packages (pydantic, pytz, requests, pyswisseph for ephemeris data).
Requires Python 3.10 or higher. pyswisseph may require a C compiler on some systems; pre-built wheels are available for common platforms.
License in practice
Licensed under AGPL-3.0 (copyleft). Any application that imports and uses kerykeion directly must also be AGPL-3.0 or compatible; proprietary or closed-source projects should use the hosted Astrologer API instead to avoid copyleft obligations.
Quickstart
from kerykeion import AstrologicalSubjectFactory
from kerykeion.chart_data_factory import ChartDataFactory
from kerykeion.charts.chart_drawer import ChartDrawer
subject = AstrologicalSubjectFactory.from_birth_data(
name="Example", year=1990, month=7, day=15,
hour=10, minute=30, lng=12.4964, lat=41.9028,
tz_str="Europe/Rome", online=False
)
chart_data = ChartDataFactory.create_natal_chart_data(subject)
ChartDrawer(chart_data=chart_data).save_svg(output_path=".", filename="natal")Verify before relying
- Precision claims for astrological calculations—what reference ephemeris or algorithm standard is used
- Performance characteristics for large-scale batch chart generation or API workloads
- Completeness of house system and ayanamsa (sidereal mode) implementations relative to standard astrological practice
Package facts
| License | AGPL-3.0 copyleft |
| Python support | Supports the current Python release >=3.10 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 8 packagespydanticpyswissephpytzrequests-cacherequestsscoursimple-ascii-tablestyping-extensions |
| Maintenance | Actively maintained 81 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 133,564 / month, #11,504 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 5 - Production/StableIntended Audience :: DevelopersIntended Audience :: Information TechnologyIntended Audience :: Science/ResearchLicense :: OSI Approved :: GNU General Public License v3 (GPLv3)Operating System :: OS IndependentProgramming Language :: Python :: 3 :: OnlyProgramming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Topic :: ReligionTopic :: Scientific/Engineering :: AstronomyTopic :: Scientific/Engineering :: VisualizationTopic :: Software DevelopmentTopic :: Software Development :: LibrariesTopic :: Software Development :: Libraries :: Python ModulesTyping :: Typed |
Evidence: kerykeion-5.12.9-py3-none-any.whl
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See also ephem · lunar_python · spiceypy · suntimes · jplephem · haversine · skyfield