Sülfeld
Neptun covers Sülfeld (Germany) through the PEGELONLINE (WSV) 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: PEGELONLINE (WSV) · Position: 52.4211, 10.6620
Request
curl -H "Authorization: Bearer mapi_YOUR_KEY" \
"https://neptun.marine-api.com/v1/levels?lat=52.4211&lon=10.6620&radius=5"