Solutions · Vessels API

Live ship positions, tracks and area alerts

Query every vessel reporting in an area, look one up by MMSI, replay its track with the sea state along the way, and get a webhook the moment a ship enters or leaves the waters you care about.

Terminal and pilot planning
Security and exclusion-zone monitoring
Offshore asset proximity alerts

Get a free API key See the webhooks

Request

# Vessels by bbox or point + radius_nm, filtered by type, status or name q
curl "https://www.seasignals.com/v1/vessels?bbox=3.5,51.5,4.5,52.2&type=cargo" \
  -H "Authorization: Bearer $SS_KEY"

Endpoints

Query it whenever you need it

GeoJSON responses with typed IDs, ISO 8601 times and units in every field name. Errors come back as {"error": {"code", "message"}}.

GET/v1/vesselsVessels by bbox or point + radius_nm, filtered by type, status or name q

GET/v1/vessels/{mmsi}One vessel: identity, position, speed, course, destination and current port

GET/v1/vessels/{mmsi}/trackTrack between from and to, with join=waves for sea state along the way

Webhooks

Or let the events come to you

Subscribe a URL once and SeaSignals POSTs a signed JSON event whenever something changes. Checked every 5 minutes.

EVENTvessel.entered_areaA vessel matching your filters started reporting inside your bbox

EVENTvessel.left_areaIt left the bbox, or stopped reporting for an hour

Filters

`bbox`	Required. [west, south, east, north], at most 20° per side
`types`	Vessel types, e.g. ["cargo", "tanker"]
`mmsi`	Only these vessels

Create a webhook

curl -X POST https://www.seasignals.com/v1/webhooks \
  -H "Authorization: Bearer $SS_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "url": "https://example.com/hooks/seasignals",
  "product": "vessels",
  "events": [
    "vessel.entered_area",
    "vessel.left_area"
  ],
  "filters": {
    "bbox": [
      3.5,
      51.5,
      4.5,
      52.2
    ],
    "types": [
      "cargo",
      "tanker"
    ]
  }
}'

POST to your URL

{
  "id": "evt_3kV9q2mXw8rT1yLp0aZc4nB7",
  "type": "vessel.entered_area",
  "created_at": "2026-10-29T09:00:12Z",
  "webhook": "webhook:42",
  "data": {
    "type": "Feature",
    "id": "vessel:mmsi:244123456",
    "geometry": {
      "type": "Point",
      "coordinates": [
        3.82,
        51.97
      ]
    },
    "properties": {
      "name": "NORDIC STAR",
      "type": "cargo",
      "sog_kn": 11.2,
      "cog_deg": 84.0,
      "destination": "NL RTM",
      "position_time": "2026-10-29T08:41:12Z"
    }
  }
}

Delivery

Signed, retried, logged

Signed: every request carries SeaSignals-Signature, an HMAC-SHA256 of the timestamp and body with your webhook secret.
Retried: anything but a 2xx within 10 seconds is retried after 1 min, 5 min, 30 min, 2 h and 6 h.
Logged: GET /v1/webhooks/{id} shows recent deliveries, and POST /v1/webhooks/{id}/test sends a test event.
Safe to retry: use the event id to ignore a delivery you've already handled.

// header: SeaSignals-Signature: t=1761729600,v1=5f2b…
const [t, v1] = header.split(",").map((p) => p.split("=")[1]);
const expected = crypto.createHmac("sha256", process.env.SS_WEBHOOK_SECRET)
  .update(`${t}.${rawBody}`).digest("hex");
const ok = crypto.timingSafeEqual(Buffer.from(v1), Buffer.from(expected))
  && Date.now() / 1000 - Number(t) < 300;

import hashlib, hmac, os, time

t, v1 = (part.split("=")[1] for part in header.split(","))
expected = hmac.new(os.environ["SS_WEBHOOK_SECRET"].encode(),
                    f"{t}.{raw_body}".encode(), hashlib.sha256).hexdigest()
ok = hmac.compare_digest(v1, expected) and time.time() - int(t) < 300

t, v1 = header.split(",").map { _1.split("=").last }
expected = OpenSSL::HMAC.hexdigest("SHA256", ENV["SS_WEBHOOK_SECRET"], "#{t}.#{raw_body}")
ok = ActiveSupport::SecurityUtils.secure_compare(v1, expected) && Time.now.to_i - t.to_i < 300

One key for every API

Port Calls API

Arrivals, departures and time in port

Port Delays API

Anchorage queues and overstays, port by port

Storms API

Tropical cyclones with cones, tracks and approach alerts

Marine Life API

Whale, dolphin, shark and turtle sightings

Try the Vessels API free

The free trial includes every API and up to 5 webhooks, 1,000 requests a day and 14 days of history.

Get a free API key API overview