Progressions
Astrological Progression API family
BetaThe progression API family lets you generate progressed charts, search exact hits in a date window, and build event calendars across five systems: secondary, converse secondary, tertiary, quotidian, and quaternary.
All progression endpoints are still in beta. Expect continued refinement to curation, editorial ranking, and some response details while the contract stabilizes.
Quick start
If you are new to progressions, start with the secondary chart endpoint. It is the most familiar progression system and the easiest integration point before moving to the search and calendar utilities.
Every chart endpoint uses the same outer natal block. What changes is the route and the progression body key, such as secondary_progression or tertiary_progression.
curl -X POST "https://api.freeastroapi.com/api/v1/western/progressions/secondary" \
-H "Content-Type: application/json" \
-H "x-api-key: YOUR_API_KEY" \
-d '{
"natal": {
"name": "User",
"datetime": "1990-01-01 12:00",
"time_known": true,
"location": {
"city": "London",
"lat": 51.5074,
"lng": -0.1278,
"tz_str": "AUTO"
}
},
"secondary_progression": {
"target_date": "2026-03-30"
}
}'Need 1 Year = 1 Degree?
That workflow is documented as symbolic directions, not secondary progressions. Use it when you want fixed Ptolemaic-key zodiacal timing: method=zodiacal, direction=direct, and key=ptolemy.
Which endpoint should I use?
I want a progressed chart
Use one of the chart routes. Start with secondary unless you already know you want tertiary, converse, quotidian, or quaternary.
I want exact hits in a date window
Use exact aspects when you want exact progressed-to-natal or progressed-to-progressed hits over time.
I want sign or house changes
Use exact ingresses to search for sign ingresses or house ingresses inside a date range.
I want an event feed
Use the calendar endpoints for curated upcoming events such as exact aspects, ingresses, stations, and moon phases.
Choose a progression system
Secondary
The classic day-for-year progression. Best default choice if you want the standard progressed chart most astrologers expect.
Converse Secondary
The same secondary logic, but moving backward from birth. Useful for specialized research or reverse symbolic timing.
Tertiary
A faster progression keyed to the lunar month. Better when you want shorter-cycle symbolic timing than secondary.
Quotidian
A symbolic solar-arc-style progression. Good when you want a directed chart with a clear arc basis instead of a progressed datetime.
Quaternary
A faster symbolic system using a lunar-month-for-year mapping. Useful for compressed timing and experimentation.
How to choose an operation
Chart endpoint
Use the system page when you want the full progressed chart or response_mode=table.
Utility endpoints
Use the shared pages for exact ingresses, exact aspects, and calendars. The route pattern is the same across all five systems.
Timezone behavior
Progressions use the newer nested natal contract, including natal timezone handling.
- No
target_location: date-only and naive target datetimes are treated as UTC. - With
target_location: date-only and naive target datetimes are interpreted in that local timezone. target_location.tz_str = "AUTO"resolves from the target city and coordinates.
This applies to chart target_date, exact-search windows, and calendar windows.