Arkö
Neptun covers Arkö (Sweden) through the SMHI network. One GET request returns its readings as JSON — in the same shape as every other network Neptun serves, so you write the parsing once.
Source: SMHI · Position: 58.4831, 16.9637
Request
curl -H "Authorization: Bearer mapi_YOUR_KEY" \
"https://neptun.marine-api.com/v1/levels?lat=58.4831&lon=16.9637&radius=5"