Elevation API.

// Elevation profile for a route geometry
async function getElevationProfile(routeCoords) {
  // routeCoords: [[lon,lat], [lon,lat], ...]
  const coords = routeCoords
    .map(c => c.join(","))
    .join("|");

  const res = await fetch(
    `/api/elevation?coordinates=$${coords}&include_slope=true`
  );

  const { results, summary } = await res.json();

  // Flag segments steeper than 15%
  const steep = results.filter(
    p => p.slope_pct != null && p.slope_pct > 15
  );

  return { results, summary, steep };
}

import requests

BASE = "https://api.farun.io/v1/elevation"
HEADERS = {
    "X-RapidAPI-Key":  "YOUR_KEY",
    "X-RapidAPI-Host": "farun-maps.p.rapidapi.com",
}

def elevation_profile(coords: list[tuple]):
    """coords: [(lon, lat), (lon, lat), ...]"""
    path = "|".join(
        f"{lon},{lat}"
        for lon, lat in coords
    )
    r = requests.get(BASE, headers=HEADERS,
        params={
            "coordinates":   path,
            "include_slope": "true",
        }
    )
    data = r.json()
    steep = [p for p in data["results"]
             if p["slope_pct"] and p["slope_pct"] > 15]
    return data["results"], data["summary"], steep

# Elevation profile - route waypoints with slope
curl "https://api.farun.io/v1/elevation" \
  -H "X-RapidAPI-Key: YOUR_KEY" \
  -H "X-RapidAPI-Host: farun-maps.p.rapidapi.com" \
  -G \
  --data-urlencode \
    "coordinates=77.20,28.61|77.22,28.63|77.25,28.65" \
  --data-urlencode "include_slope=true" \
  --data-urlencode "units=metres"

# Response: JSON with results[] and summary
# summary.ascent_m, summary.max_slope_pct, ...