Documentation
From your own ephemeris code to the API
Replace self-hosted Swiss Ephemeris code with API calls: what maps to what, how to compare results, and when not to move.
If you already call the Swiss Ephemeris yourself, you have solved the hardest part of positions. What you may not want to keep solving is everything around them: time zones, licensing, nakshatra and dasha logic, doshas, translations and updates.
When not to move
If you only need raw positions at high volume, and your licence is in order, your own code is cheaper and faster. Move when the calculations around the positions become the larger cost.
A licence question to check: the Swiss Ephemeris is free under the AGPL, which has conditions for software offered over a network, or under a paid professional licence. Calling an API means that you do not need your own.
What maps to what
| You call | Use |
|---|---|
swe_calc_ut with SEFLG_SIDEREAL | planet-positions |
swe_houses_ex | bhav-chalit, western-house-cusps |
swe_set_sid_mode | The ayanamsha field |
swe_get_ayanamsa_ut | ayanamsha-list, or ayanamsha in any chart |
swe_rise_trans | sun-moon-timings |
swe_sol_eclipse_when_glob | eclipses |
| Your own dasha code | vimshottari-dasha, dasha-at-date |
Compare before you switch
Run both side by side on a sample of real births, and compare by longitude:
curl https://api.96astroapi.com/v1/vedic-charts/planet-positions \
-H "Authorization: Bearer $ASTRO_API_KEY" \
-H "Content-Type: application/json" \
-d '{ "datetime": "1990-10-18T14:30:00", "timezone": "Asia/Kolkata", "latitude": 28.6139, "longitude": 77.209 }'Small differences usually have one of these causes:
- The node: we default to the true node. Send
"node": "mean"if you usedSE_MEAN_NODE. - Apparent or true: we use apparent positions, without
SEFLG_TRUEPOSorSEFLG_NOABERR. - The ayanamsha: the default is Lahiri. Check that yours is the same.
- Your offset: we resolve the zone's offset for that date. A fixed offset in your code may differ for old dates.
- Data files: without the
.se1files, the library falls back to a less precise model.
See How charts are computed for the full list.
Moving in stages
Move the logic you least want to own first, such as doshas, matching or translations, and keep your own positions for now. Then move the rest once the numbers agree.