Royan
Neptun covers Royan (France) through the CANDHIS (Cerema) 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: CANDHIS (Cerema) · Position: 45.6100, -1.0317
Request
curl -H "Authorization: Bearer mapi_YOUR_KEY" \
"https://neptun.marine-api.com/v1/levels?lat=45.6100&lon=-1.0317&radius=5"