SVG Composite Chart Generator

POST/api/v1/natal/chart/composite

Generate a standalone midpoint composite SVG/PNG chart from two people. The endpoint reuses the natal SVG styling contract while building one composite wheel from midpoint planets and, when both birth times are known, midpoint houses and angles.

If either person has time_known: false, the composite falls back to an untimed chart and hides houses and angles.

Related SVG Endpoints

SVG Natal Chart

Single-person natal wheel.

SVG Synastry Chart

Bi-wheel relationship overlay using both charts directly.

Full URL

https://api.freeastroapi.com/api/v1/natal/chart/composite

Top-level Parameters

Request-level controls for the composite endpoint.

Parameter	Type	Required	Default	Description
person_a	object	Yes	-	Primary person object. Also controls output format, size, theme, and chart styling.
person_b	object	Yes	-	Secondary person object used to build midpoint positions.
show_aspects	boolean	No	true	Show aspect lines inside the composite wheel.
chart_config	object	No	null	Optional top-level chart style overrides merged after person_a.chart_config.
custom_planet_color	string\|null	No	null	Top-level alias for composite planet color.
custom_sign_color	string\|null	No	null	Top-level alias for sign symbol color.
custom_house_color	string\|null	No	null	Top-level alias for house number color.
custom_sign_bg_color	string\|null	No	null	Single sign background color alias.
custom_house_bg_color	string\|null	No	null	Single house background color alias.
show_sign_background	boolean\|null	No	null	Explicit sign background toggle alias.
show_house_background	boolean\|null	No	null	Explicit house background toggle alias.
custom_sign_colors	string[]\|null	No	null	Per-sign background colors alias.
custom_house_colors	string[]\|null	No	null	Per-house background colors alias.
sign_background_opacity	float\|null	No	null	Sign background opacity alias.
house_background_opacity	float\|null	No	null	House background opacity alias.
show_retrograde_markers	boolean\|null	No	null	Top-level alias for retrograde markers on degree labels.
retrograde_marker_style	string\|null	No	null	Top-level alias for retrograde marker style: R or rx.

person_a / person_b Schema

Both nested objects follow the natal SVG request schema.

Parameter	Type	Required	Default	Description
name	string	No	User	Display name for the person.
year	integer	Yes	-	Birth year.
month	integer	Yes	-	Birth month (1-12).
day	integer	Yes	-	Birth day (1-31).
hour	integer	No	12	Birth hour (0-23).
minute	integer	No	0	Birth minute (0-59).
time_known	boolean	No	true	When either person is untimed, the composite falls back to planets-only and hides houses/angles.
city	string	No	-	Birth city. Optional when lat/lng are provided.
lat	float	No	auto	Optional latitude override. Required with lng if city is omitted.
lng	float	No	auto	Optional longitude override. Required with lat if city is omitted.
tz_str	string	No	AUTO	Timezone or AUTO.
format	string	No	svg	Output format from person_a only: 'svg' or 'png'.
size	integer	No	700	Output width/height in px from person_a only.
theme_type	string	No	light	Theme from person_a only: 'light', 'dark', or 'mono'.
display_settings	object	No	null	Optional body visibility toggles. Both nested objects are accepted and merged into the composite display config.
chart_config	object	No	null	Advanced styling settings inherited from the natal SVG contract.

display_settings (nested)

Optional body visibility toggles inside each person object.

Parameter	Type	Required	Default	Description
sun	boolean	No	true	Show Sun.
moon	boolean	No	true	Show Moon.
mercury	boolean	No	true	Show Mercury.
venus	boolean	No	true	Show Venus.
mars	boolean	No	true	Show Mars.
jupiter	boolean	No	true	Show Jupiter.
saturn	boolean	No	true	Show Saturn.
uranus	boolean	No	true	Show Uranus.
neptune	boolean	No	true	Show Neptune.
pluto	boolean	No	true	Show Pluto.
north_node	boolean	No	true	Show North Node.
south_node	boolean	No	false	Show South Node.
chiron	boolean	No	true	Show Chiron.
ceres	boolean	No	false	Show Ceres.
pallas	boolean	No	false	Show Pallas.
juno	boolean	No	false	Show Juno.
vesta	boolean	No	false	Show Vesta.
asc	boolean	No	true	Show Ascendant glyph when timed.
ic	boolean	No	false	Show IC glyph when timed.
dsc	boolean	No	false	Show Descendant glyph when timed.
mc	boolean	No	false	Show Midheaven glyph when timed.
lilith	boolean	No	true	Show mean Lilith.
mean_lilith	boolean	No	false	Alias toggle for mean Lilith.
true_lilith	boolean	No	false	Show true Lilith.
eris	boolean	No	false	Show Eris.
eros	boolean	No	false	Show Eros.
vertex	boolean	No	false	Show Vertex.
part_of_fortune	boolean	No	false	Show Part of Fortune.

chart_config

Composite styling uses the same advanced settings as the SVG/PNG Chart Generator. The fields below are accepted by this endpoint even if some are more relevant to other SVG modes.

Parameter	Type	Required	Default	Description
stroke_width	integer	No	1	Base SVG stroke width.
stroke_opacity	float	No	1.0	Global stroke opacity.
font	string	No	sans-serif	SVG font family.
font_size_fraction	float	No	0.35	Base label scaling factor.
inner_min_degree	float	No	9.0	Minimum spacing for inner wheel placements.
outer_min_degree	float	No	8.0	Minimum spacing for outer wheel placements.
margin_factor	float	No	0.04	Outer SVG margin factor.
ring_thickness_fraction	float	No	0.15	Fallback ring thickness fraction.
sign_ring_thickness_fraction	float\|null	No	0.16	Sign ring thickness fraction.
house_ring_thickness_fraction	float\|null	No	0.05	House ring thickness fraction.
center_disk_fraction	float\|null	No	0.45	Center disk radius fraction.
planet_symbol_scale	float\|null	No	0.35	Planet glyph scale.
sign_symbol_scale	float\|null	No	0.6	Sign glyph scale.
house_number_scale	float\|null	No	0.25	House number scale.
chart_background	string\|null	No	null	Chart background color.
custom_planet_color	string\|null	No	null	Override all planet colors.
custom_sign_color	string\|null	No	null	Override all sign symbol colors.
custom_house_color	string\|null	No	#000000	Override house number color.
sign_line_width	float\|null	No	2.0	Sign separator width.
sign_line_color	string\|null	No	black	Sign separator color.
house_line_width	float\|null	No	1.0	House separator width.
house_line_color	string\|null	No	#919191	House separator color.
sign_ring_inner_width	float\|null	No	1.5	Inner sign ring width.
sign_ring_inner_color	string\|null	No	#000000	Inner sign ring color.
sign_ring_outer_width	float\|null	No	2.0	Outer sign ring width.
sign_ring_outer_color	string\|null	No	#000000	Outer sign ring color.
house_ring_inner_width	float\|null	No	1.0	Inner house ring width.
house_ring_inner_color	string\|null	No	#000000	Inner house ring color.
house_ring_outer_width	float\|null	No	1.0	Outer house ring width.
house_ring_outer_color	string\|null	No	#000000	Outer house ring color.
asc_line_width	float\|null	No	3.0	ASC axis width.
asc_line_color	string\|null	No	#000000	ASC axis color.
dsc_line_width	float\|null	No	3.0	DSC axis width.
dsc_line_color	string\|null	No	#000000	DSC axis color.
mc_line_width	float\|null	No	3.0	MC axis width.
mc_line_color	string\|null	No	#000000	MC axis color.
ic_line_width	float\|null	No	3.0	IC axis width.
ic_line_color	string\|null	No	#000000	IC axis color.
sign_tick_width	float\|null	No	0.5	Degree tick width.
sign_tick_color	string\|null	No	#000000	Degree tick color.
aspect_conjunction_width	float\|null	No	3.0	Conjunction line width.
aspect_conjunction_color	string\|null	No	#1A1A1A	Conjunction line color.
aspect_opposition_width	float\|null	No	3.0	Opposition line width.
aspect_opposition_color	string\|null	No	#C00000	Opposition line color.
aspect_trine_width	float\|null	No	2.2	Trine line width.
aspect_trine_color	string\|null	No	#0047AB	Trine line color.
aspect_square_width	float\|null	No	2.6	Square line width.
aspect_square_color	string\|null	No	#C00000	Square line color.
aspect_sextile_width	float\|null	No	1.9	Sextile line width.
aspect_sextile_color	string\|null	No	#0047AB	Sextile line color.
aspect_quincunx_width	float\|null	No	1.7	Quincunx line width.
aspect_quincunx_color	string\|null	No	#2E7D32	Quincunx line color.
scale_adj_factor	float	No	600.0	Glyph scale adjustment baseline.
pos_adj_factor	float	No	2.2	Glyph position adjustment baseline.
show_color_background	boolean	No	false	Enable color background mode.
show_sign_background	boolean\|null	No	null	Show per-sign backgrounds.
show_house_background	boolean\|null	No	null	Show per-house backgrounds.
custom_sign_colors	string[]\|null	No	null	Per-sign background colors.
custom_house_colors	string[]\|null	No	null	Per-house background colors.
sign_background_opacity	float\|null	No	null	Sign background opacity.
house_background_opacity	float\|null	No	null	House background opacity.
custom_sign_bg_color	string\|null	No	null	Single sign background color.
custom_house_bg_color	string\|null	No	null	Single house background color.
show_retrograde_markers	boolean	No	false	Show retrograde markers on degree text.
retrograde_marker_style	string	No	R	Retrograde marker style: R or rx.
show_inner_ring_angles	boolean\|null	No	false	Renderer flag inherited from the shared config model.
show_data2_house_wheel	boolean\|null	No	false	Renderer flag inherited from the shared config model.
show_data2_house_numbers	boolean\|null	No	false	Renderer flag inherited from the shared config model.
invert_data2_orientation	boolean\|null	No	null	Renderer flag inherited from the shared config model.
invert_data2_radial_placement	boolean\|null	No	null	Renderer flag inherited from the shared config model.
data2_house_ring_scale	float\|null	No	0.62	Renderer flag inherited from the shared config model.
data2_house_ring_extra_width_px	float\|null	No	3.0	Renderer flag inherited from the shared config model.
data2_house_line_width	float\|null	No	1.0	Renderer flag inherited from the shared config model.
data2_house_line_color	string\|null	No	#919191	Renderer flag inherited from the shared config model.
data2_house_ring_inner_width	float\|null	No	1.0	Renderer flag inherited from the shared config model.
data2_house_ring_inner_color	string\|null	No	#000000	Renderer flag inherited from the shared config model.
data2_house_ring_outer_width	float\|null	No	1.0	Renderer flag inherited from the shared config model.
data2_house_ring_outer_color	string\|null	No	#000000	Renderer flag inherited from the shared config model.
data2_custom_house_color	string\|null	No	#000000	Renderer flag inherited from the shared config model.
data2_asc_line_width	float\|null	No	3.0	Renderer flag inherited from the shared config model.
data2_asc_line_color	string\|null	No	#000000	Renderer flag inherited from the shared config model.
data2_dsc_line_width	float\|null	No	3.0	Renderer flag inherited from the shared config model.
data2_dsc_line_color	string\|null	No	#000000	Renderer flag inherited from the shared config model.
data2_mc_line_width	float\|null	No	3.0	Renderer flag inherited from the shared config model.
data2_mc_line_color	string\|null	No	#000000	Renderer flag inherited from the shared config model.
data2_ic_line_width	float\|null	No	3.0	Renderer flag inherited from the shared config model.
data2_ic_line_color	string\|null	No	#000000	Renderer flag inherited from the shared config model.

Sample Code

curl -X POST "https://api.freeastroapi.com/api/v1/natal/chart/composite" \
 -H "Content-Type: application/json" \
 -H "x-api-key: YOUR_API_KEY" \
 -d '{
  "person_a": {
    "year": 1990,
    "month": 5,
    "day": 15,
    "city": "London"
  },
  "person_b": {
    "year": 1992,
    "month": 8,
    "day": 6,
    "city": "Paris"
  }
}' --output composite_chart.svg