curl --request POST \
  --url https://api.footstep.ai/v1/routing/matrix \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '
{
  "sources": [
    {
      "lat": 51.5322,
      "lon": -0.124
    },
    {
      "lat": 51.5055,
      "lon": -0.0754
    }
  ],
  "targets": [
    {
      "lat": 51.5178,
      "lon": -0.0823
    },
    {
      "lat": 51.5055,
      "lon": -0.0862
    }
  ]
}
'

{
  "sources": [
    {
      "lat": 0,
      "lon": 0
    }
  ],
  "targets": [
    {
      "lat": 0,
      "lon": 0
    }
  ],
  "matrix": [
    [
      {
        "distance_m": 123,
        "duration_s": 123
      }
    ]
  ]
}