Geomag API
Access magnetic declination, inclination, total field intensity, from the WMM2020 valid for years 2020.0 - 2025.0
{
"declination": {
"units": "Deg",
"value": 34.144142150878906
},
"grid_variation": {
"units": -65.8558578491211,
"value": "Deg"
},
"inclination": {
"units": "Deg",
"value": 87.98262786865234
},
"total_intensity": {
"units": "nT",
"value": 58421.87109375
}
}
Response example. If you want to see more check the documentation.