Field	Type	Required	Notes
`station`	string	yes	CO-OPS station id, e.g. 8518750 or cb0102
`product`	string	no	One of water_level, predictions, currents; default water_level
`beginDate`	string	yes	ISO date YYYY-MM-DD
`endDate`	string	no	ISO date YYYY-MM-DD; defaults to beginDate, at most 7 days
`datum`	string	no	Vertical datum for water_level and predictions, one of MLLW, MLW, MSL, MTL, MHW, MHHW, NAVD, STND; default MLLW
`units`	string	no	english or metric; default english

Example input:

{
  "station": "8518750",
  "product": "water_level",
  "beginDate": "2026-08-10",
  "endDate": "2026-08-11"
}

Metered

The 402 quotes a ceiling — the price of the declared cap, 7 days — and settlement is for what the call actually used. A small request settles for less than it was quoted, so read the quote as an upper bound rather than a price.

Cost and provenance


Price	$0.005 per call, metered per days
Source	NOAA CO-OPS Data API (api.tidesandcurrents.noaa.gov), public domain
Licence	public-domain

Why call it rather than answer from memory

A port, dredging or coastal-survey agent needs the measured water level or current at a specific station over the days it is planning around, which is sensor data no model holds.

Calling it

A skill is loaded on its own, so this document has to be enough by itself. It does not assume the general fittings skill is also loaded. call.mjs ships alongside this file; if it is missing (this document reached you without the rest of the skill), fetch it once with curl -sO https://fittings.sh/skill/call.mjs.

Free, and needs no wallet. Read the schema and see what a call would cost:

curl -s https://fittings.sh/catalog/noaa.coops-station-data | jq

Paying. The endpoint answers 402 Payment Required with a signed quote, you sign an authorization, and a facilitator settles it — you never send a transaction and never pay gas. Before it spends anything, the client checks its own hash against the gateway and refuses rather than sign with logic the gateway has moved past:

# Dry run. Prints the quote and pays nothing, because no key is set.
node call.mjs noaa.coops-station-data station=8518750 product=water_level beginDate=2026-08-10 endDate=2026-08-11

# For real: a wallet holding USDC on Base, and nothing else.
export FITTINGS_PRIVATE_KEY=0x...
node call.mjs noaa.coops-station-data station=8518750 product=water_level beginDate=2026-08-10 endDate=2026-08-11

Spending is never a side effect of curiosity: with no FITTINGS_PRIVATE_KEY the client fetches the quote and stops. FITTINGS_MAX_PRICE caps what it will pay without asking, and defaults to $0.05.

Use a throwaway wallet holding a few dollars, not a main one. The key sits in plaintext wherever the agent runs, and the whole cost of entry is USDC on Base — no account, no API key, and no ETH, because the payer signs off-chain and the facilitator broadcasts and pays the gas.

Writing your own client instead of using this one? @x402/core and @x402/evm on npm, and the fittings skill records the two things that cost real debugging time: the challenge is in a response header rather than the body, and it must be re-signed from the exact request being retried.

If this is not the right service, https://fittings.sh/catalog/search?q=... searches all of them for free.

fittings-noaa-coops-station-data

NOAA CO-OPS station observations

The call