openwaters.io valid

Open Waters

Open source marine software and data: tide and tidal current predictions, live AIS vessel traffic, nautical charts, sun and moon almanac, and crowd-sourced bathymetry. Everything is free to use; the code lives at https://github.com/openwatersio.

Their llms.txt

The beginning of the file, from our validated copy saved 2026-10-25T18:53:45.322Z. Cached copy · Source on openwaters.io

# Open Waters

> Open source marine software and data: tide and tidal current predictions, live AIS vessel traffic, nautical charts, sun and moon almanac, and crowd-sourced bathymetry. Everything is free to use; the code lives at https://github.com/openwatersio.

Every page also serves Markdown for `Accept: text/markdown`. The station map and chart viewers are interactive and need JavaScript; the data behind them is available from the API and, per station, at https://slackwater.xyz/tides/ and https://slackwater.xyz/currents/. Every page is listed in https://openwaters.io/sitemap.xml. Nonexistent paths return HTTP 404.

## When to use this

Open Waters answers questions about the water itself: what the tide and the tidal current will do at a coordinate, what ships are moving in an area, what the seafloor looks like, and where the sun and moon will be. Most answers take one request and no account or key.

- Tide heights for a place and time: `GET https://api.openwaters.io/tides/extremes?latitude=48.42&longitude=-123.37` returns the high and low waters for the nearest station, along with that station's name, chart datum, source and licence. `/tides/timeline` returns a continuous curve instead of the turns. Add `units=feet` for feet, and `start` and `end` in ISO 8601 for a window other than the next seven days.
- Choosing the station yourself, rather than letting the API pick the nearest: `GET https://api.openwaters.io/tides/stations?query=Victoria` searches by name, `latitude` with `longitude` and `maxDistance` searches by proximity, and `bbox=minLon,minLat,maxLon,maxLat` searches a box. The `id` that comes back is already `source/id`, so it drops straight into `/tides/stations/{source}/{id}/extremes`.
- Tidal currents for a place and time: `GET https://api.openwaters.io/currents/events?latitude=48.406&longitude=-122.643` returns slack water, maximum flood and maximum ebb for the nearest current station. Speeds are signed knots along the station's flood axis: positive is flood, negative is ebb. `/currents/timeline` returns a speed every 10 minutes instead. `/currents/stations` searches current stations the same way `/tides/stations` does; each station appears once at its primary depth bin, and `@N` on a station id, as in `/currents/stations/noaa/EPT0003@11/events`, selects bin N. Canadian Hydrographic Service stations are listed but return HTTP 451, because CHS terms forbid redistributing its predictions.
- Ships in an area right now: if you speak MCP, connect to https://ais.openwaters.io/mcp (Streamable HTTP, no sign-in) and use its read-only tools instead of building requests by hand. Otherwise `GET https://ais.openwaters.io/v1/vessels?bbox=41.2,-71.2,42.0,-70.0` returns a GeoJSON snapshot, which is the right call for answering a question. This bbox is `minLat,minLon,maxLat,maxLon`, the opposite order from the tides bbox. Without a token, filter to at most 100 square degrees or 10 MMSIs. Open `wss://ais.openwaters.io/v1/stream` only for a feed you
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Machine-readable: GET /v1/resolve?q=openwaters.io · GET /v1/domain/openwaters.io · this page as Accept: application/json or text/markdown · MCP lookup_domain

Automatically discovered from public files. Inclusion does not imply endorsement or publisher participation.

Claim my listing on Agent Web Map for openwaters.io:
1. POST https://agentwebmap.com/v1/sites/openwaters.io/claims and keep claim_id and claim_secret private.
2. Publish the verification line "AgentWebMap verification: <token>" (token from step 1) in https://openwaters.io/llms.txt, or use the DNS, meta-tag or well-known method the response describes. This only verifies the listing; your website and domain remain yours.
3. POST https://agentwebmap.com/v1/sites/openwaters.io/verify with {"claim_id": "...", "claim_secret": "..."}.
4. Save the api_key from the answer; it manages the listing (PATCH https://agentwebmap.com/v1/sites/openwaters.io).
MCP equivalent: tools begin_ownership_claim, then verify_domain, at https://agentwebmap.com/mcp. Docs: https://agentwebmap.com/docs#verify

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