API reference
Build with the complete Human Design system.
Search 44 documented operations across REST, Agent HTTP and MCP. Every page is static, shareable and indexable.
Charts
Generate bodygraph, transit, relationship, group, progressed and batch Human Design charts.
- GET /hd-data
- GET /v2/hd-data
- GET /v3/hd-data
- GET /hd-data-transit
Forecasting & Returns
Build forecasts, returns, calendars and live planetary experiences.
- GET /planetary-positions
- GET /planetary-forecast
- GET /solar-return
- GET /lunar-return
Reference Library
Query structured knowledge for gates, channels, centers and profiles.
- GET /library/gates
- GET /library/gates/{gateNumber}
- GET /library/channels
- GET /library/channels/{channelId}
Discovery
Resolve locations and search the Human Design celebrity database.
- GET /locations
- GET /celebrity/search
- GET /celebrity/{slugOrId}
Agent HTTP
Purpose-built JSON tools for assistants, automations and agent runtimes.
- POST /agent/v1/tools/resolve-timezone
- POST /agent/v1/tools/generate-chart
- POST /agent/v1/tools/get_chart
- POST /agent/v1/tools/generate-composite-chart
Model Context Protocol
Connect MCP-compatible clients to the exact calculation or account tools their credential permits.
- POST /
- GET /
- DELETE /
- POST /mcp
Birth times are local wall clock times
Send the birth date and time exactly as it read on the clock where the person was born, with no Z and no UTC offset. Give the zone separately as an IANA identifier.
Date=1990-05-15T14:30:00 with Timezone=America/New_York means half past two in the afternoon in New York.
A value carrying Z or an offset does not name a wall clock time on its own. Something has to decide which zone to read it in, and that decision changes the chart.
Values ending in Z or a numeric offset are deprecated. They are still accepted for now: the API reads them as UTC and calculates from that, and the response carries Deprecation: true along with a Warning header naming this rule. They will stop being accepted, and the date will be announced in advance.
A wall clock time that cannot name one moment is refused before any calculation unit is used:
| Error code | When it is returned |
|---|---|
nonexistent_local_time | A daylight-saving change skipped that wall time, so it never happened in that zone. |
ambiguous_local_time | The wall time falls inside a daylight-saving fold, so it happened twice in that zone. |
future_birth_datetime | The birth time is in the future. |
invalid_birth_datetime_format | The value is not a wall clock time. After the cutover this covers Z and numeric offsets too. |
Transit, forecast and progression dates use the same format, but they are allowed to be in the future.