API Terms

Last updated: 28 September 2026 · Version 2026-09-28

These terms apply to the Predict Sea developer API at api.predictsea.com (the "API") and to anyone who holds a key for it. The website and its forecast files stay governed by the Terms of Use & Data Sources; the developer guide is the API guide, the API reference lists every endpoint, and the machine-readable specification is served at api.predictsea.com/v1/openapi.yaml. When you create a key you accept the version of these terms shown above; the key's record keeps that version and the date.

1. The service

The API is a free beta. It answers derived questions — a point forecast, model agreement, the automatic model choice, tropical-cyclone tracks and US federal buoy observations — from the same published forecast releases the website shows. Keys are self-serve: sign up at api.predictsea.com/signup and confirm your email address through the link we send, and the key is shown to you once and emailed to you. We may also issue keys by hand. Endpoints, quotas and these terms may change during the beta; we announce changes as described in section 7.

2. Keys

A key is confidential. There is one active key per person or organisation (one per email address); do not share it.
The emailed copy of a key is a risk: a mailbox keeps it and can forward it. Delete that email once the key is stored in your server's secret store or environment.
Keep it server-side only: send it in the X-Api-Key header from your own servers. Never put it in a web page, a browser script, a mobile or desktop app binary, a URL or a public repository — anything shipped to users can be extracted, and the API refuses a key in a URL.
If a key is lost or leaks, replace it at api.predictsea.com/manage: you get a new key and the old one stops working at once. Tell us about a leak too. We may revoke a key that has been exposed.

3. Quotas and fair use

Each key has a per-minute limit and a daily quota in weight units (a point forecast weighs 1, a comparison 1 per model compared); every answer reports what is left. Self-serve keys start at 30 requests a minute and 1,000 weight units a day (UTC); keys we issue by hand start at 60 and 5,000. Past a limit the API answers 429 with a Retry-After header: wait that long before retrying. Do not circumvent the limits — not with several keys, several addresses or any other means. Cache answers on your side where you can: forecasts change with each model run, a few times a day. If you need more, ask.

4. Attribution passthrough

The forecasts are other agencies' data, modified by Predict Sea, and their licences travel with them. Every answer carries an attribution list naming the providers of the data it contains. Wherever you show that data to your users you must show, for the providers listed:

the provider's credit and, for CC BY 4.0 data, a link to the licence (license_url);
for ECMWF data (ECMWF, AIFS, ECMWF storm tracks): ECMWF's notice, copyright line and disclaimer as given, and the words contains modified ECMWF data;
for Environment and Climate Change Canada data (GDPS, GDWPS): the exact wording Data Source: Environment and Climate Change Canada, with no ECCC or Government of Canada logos or crests;
for Deutscher Wetterdienst data (ICON, ICON-EU, GWAM, EWAM): DWD's credit, which names the licence and the modification;
the statements that NOAA and ECCC do not endorse Predict Sea or your product, and nothing that suggests any agency does;
the modification statement of the answer (modification): the data is not the agencies' original output;
for storm tracks: each feed's credit and that the tracks are guidance, not an official warning;
for observations: "NOAA NDBC buoy observations (public domain)". The API serves US federal stations only.

A credit with a link to the attribution details, one tap away from the data, is enough on a small screen. We also ask — it is not a condition — that you name Predict Sea as the source of the processed forecasts.

Every answer carries a notice: forecast guidance only — not for navigation. Show it, or words to the same effect, with the data. Never present the data as an official forecast or warning, or as endorsed by any meteorological service; it has no official status. Tell your users to check the official marine forecasts and warnings for their area before and during a passage, as the website's safety notice does.

6. The data's licence

The data stays under its upstream licences, listed on the Terms page (public domain, CC BY 4.0, the ECCC open-data licence). These terms govern the service — keys, quotas, fair use — and add no restriction on the data beyond those licences; CC BY 4.0 does not allow us to add any.

7. No service level

Availability, latency and freshness are not guaranteed. The API can be down, slow or serving a run that is late, and it may be discontinued. Version 1 changes additively (new fields and endpoints); a change that breaks a v1 client comes as a new version (/v2) running alongside v1 for at least 90 days, announced by email to the contact address of each key.

8. Privacy

The coordinates and other parameters of a request are used to compute the answer and are never logged or stored by the API service. Once you confirm a sign-up we store your email address, your name or organisation, what you said you will build, the terms version you accepted and the date, and the key's id, limits, dates and a hash of the key (never the key itself); per key and UTC day we count requests and their weight. Until you confirm, what you typed is held only in server memory, for up to 30 minutes. Our emails go out through Amazon Web Services (Amazon SES). The details — abuse counters, the block list, retention, and what our proxy may log — are on the Privacy page.

9. Termination

Either side may end the arrangement at any time. You can delete your account at api.predictsea.com/manage whenever you like — the key stops working at once and your details are deleted — or tell us, or simply stop calling. We revoke a key on abuse, on a breach of these terms (a missing attribution or notice, an exposed key, circumvented limits) or when the beta ends, with notice where we can give it.

10. No warranty, no liability

The API and its data are provided "as is", without warranty of any kind, express or implied, including fitness for a particular purpose. To the maximum extent permitted by law, 19 Lat accepts no liability for any loss or damage — including loss of life, injury, or damage to vessels or property — arising from use of, or inability to use, the API or its data, by you or by your users.

11. Contact

Keys, leaks, questions and notices: predictsea@outlook.com.

Terms & data sources · Privacy · Forecast status · Developer API