Every berth, every tide.

One call returns the tide table for any berth in the harbor: the times, the heights and the window your keel clears.

See the plans Talk to the harbor

1,000 calls a month freeHeights to the chart datum

$npm i @example/harbor-tides

Node.js 22 or later

One call returns

The whole tide, per berth.

High and low water

Times and heights for 14 days, at the berth itself.

Keel clearance

The hours a given draft clears, from the charted depth.

Datum named

Every height names its chart datum.

GET/v1/berths/{berth}/tidesOne berth, 14 days

Request

curl https://api.harbor-tides.example/v1/berths/pier-4/tides?days=1

Response200 OK

{
  "berth": "pier-4",
  "datum": "chart datum",
  "tides": [
    { "at": "04:12", "type": "low", "m": 0.6 },
    { "at": "10:31", "type": "high", "m": 4.1 },
    { "at": "16:40", "type": "low", "m": 0.8 },
    { "at": "22:58", "type": "high", "m": 3.9 }
  ]
}

The API

Four routes, one shape.

GET/v1/berths
Every berth in a harbor, with its charted depth
GET/v1/berths/{berth}/tides
High and low water for one berth
GET/v1/berths/{berth}/window
The hours a given draft clears
POST/v1/alerts
A webhook before a window closes

For the bridge

Plan the passage, not the math.

Windows, not tables
Ask for a draft and get the hours it clears.
Alerts before the turn
A webhook fires an hour before a window closes.
One source per berth
Each answer names its station and its datum.

A 3.2 m draft at pier 4

{ "draft": 3.2, "opens": "08:05", "closes": "12:50" }

Where it runs

In the tools a crew opens.

In a script

One package, typed.

window.ts

const w = await tides.window('pier-4', 3.2);

In an agent

One prompt, one berth.

Ask an agent

Fetch the tide window for a 3.2 m draft at pier 4 today.

On a chart plotter

Through the Chartplot integration.

POST/v1/alerts

Requestapplication/json

{ "berth": "pier-4", "draft": 3.2 }

Response201 Created

{ "id": "al_42" }

Against station tables

The berth, not the nearest station.

Station tables

Heights at the station
One PDF per month
Datum in the small print
Math done by hand

Harbor tides

Heights at the berth
Fourteen days per call
Datum on every height
The window computed

How it works

From berth to window.

01Name the berth
02Give the draft
03Read the window
04Set an alert before it closes

Where the numbers come from

Charted, measured, named.

Charted depth

Each berth carries the depth from the latest harbor survey.

Measured tide

Predictions are corrected every 6 minutes from the harbor gauge.

Named datum

Every height says which datum it stands on.

Paste into your agent

Install @example/harbor-tides from npm.