Free, public JSON API for accessing Horizontal Gravity Index data. No authentication required. Rate-limited to 60–120 requests per minute.
All responses include X-RateLimit-Limit, X-RateLimit-Remaining, and X-RateLimit-Reset headers. If exceeded, a 429 response is returned with a retry_after field.
Returns the current composite HGI score and sub-indices.
{
"status": "ok",
"data": {
"date": "2026-02",
"hgi": 0.62,
"sub_indices": { "S": 0.53, "A": 0.61, "V": 0.72 },
"formula": "HGI(t) = α·S(t) + β·A(t) + γ·V(t)",
"weights": { "alpha": 0.333, "beta": 0.333, "gamma": 0.334 }
}
}
Returns quarterly composite HGI data from January 2022 through the latest available date.
{
"status": "ok",
"data": [
{ "date": "2022-01", "hgi": 0.05, "S": 0.02, "A": 0.05, "V": 0.08 },
...
],
"count": 18
}
Per-industry HGI breakdown for Education, Developer Tools, Enterprise SaaS, Healthcare, Financial Services, and Legal Tech.
{
"status": "ok",
"data": {
"education": { "name": "Education Technology", "phase_2026": "Accelerating", "current_hgi": 0.85, ... },
"developer_tools": { ... },
...
}
}
Annual HGI projections (2024–2030) for all tracked industries, including phase thresholds.
{
"status": "ok",
"data": [
{ "year": 2024, "composite_hgi": 0.35, "education": 0.32, ... },
...
],
"phase_thresholds": {
"emerging": { "min": 0.0, "max": 0.3 },
"accelerating": { "min": 0.3, "max": 0.7 },
"critical_absorption": { "min": 0.7, "max": 1.0 }
}
}
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