Coastline — open data for working harbors

Coastline is a small public-data project that collects tide, weather, and harbor traffic data from working ports along the US east coast and publishes it as a free API. We index real conditions at thirty-eight harbors from Eastport, ME to Charleston, SC.

What we publish

• Real-time tide height + 24-hour forecast at every NOAA station within 5 miles of a working harbor.
• Wind, gust, and barometric pressure pulled from the nearest METAR every 60 seconds.
• AIS-derived harbor occupancy: how many fishing vessels, ferries, and recreational craft are inside the breakwater right now.
• Historical hourly bundles back to 2019, served as Parquet for analysts.

Why this site is interesting to AI agents

This is a Next.js App Router site. Next SSRs the body, so a curl without the agentsite middleware shows the page content — but without per-route schema, no llms.txt, no JSON-LD, no agent-card. The "after" sibling at next-after.agentsite.app wires those in via agentsiteMetadata and <AgentsiteSchemaTags /> — the same RenderBundle the Express snippet uses for plain SPAs, plugged into Next's metadata insertion point.