tides.now

Next high/low tide predictions near a coordinate. Query: lat (-90..90), lon (-180..180), radius_km (1-500, default 100), hours (1-72, default 24). Returns { query, station:{ id, name, latitude, longitude, state, distanceKm }, predictions[{ time (station local), type: "high"|"low", heightMeters }], source }. Returns 404 NO_STATION if no NOAA tide station is within radius. Heights are referenced to MLLW (Mean Lower-Low Water).

price

$0.0010 USDC per call

method

GET/api/tides/now

payment

x402 v2 · EIP-3009 transferWithAuthorization · USDC on Base mainnet

auth

None. Sign the payment, retry with PAYMENT-SIGNATURE.

tier

Tier 0 — no paid upstream

Parameters

Name	Type	Description
`lat`required	number	min -90 · max 90
`lon`required	number	min -180 · max 180
`radius_km`	number	min 1 · max 500
`hours`	number	min 1 · max 72

Code samples

cURLbash

# 1. Probe with no auth → 402 envelope with PaymentRequirements
curl -sS 'https://2s.io/api/tides/now?lat=-90&lon=-180&radius_km=100&hours=24'

# 2. Sign + retry with PAYMENT-SIGNATURE:
curl -sS 'https://2s.io/api/tides/now?lat=-90&lon=-180&radius_km=100&hours=24' \
  -H 'PAYMENT-SIGNATURE: <base64-json-payload>'

# Or use the canonical runner (handles probe → sign → retry):
#   EVM_PRIVATE_KEY=0x... node --env-file=.env.local \
#     --experimental-strip-types scripts/x402-pay.ts \
#     'https://2s.io/api/tides/now?lat=-90&lon=-180&radius_km=100&hours=24'

TypeScript / Node — @2sio/sdktypescript

import { TwoS } from '@2sio/sdk'

const client = new TwoS({
  privateKey: process.env.EVM_PRIVATE_KEY as `0x${string}`,
})

const result = await client.tides.now({
  "lat": -90,
  "lon": -180,
  "radius_km": 100,
  "hours": 24
})

console.log('endpoint:', result.endpoint)
console.log('cost:', result.costUsd, 'USDC')
console.log('tx:', result.settlement?.txHash)
console.log('data:', result.data)

Python — 2siopython

import os
from twosio import TwoS

client = TwoS(private_key=os.environ["EVM_PRIVATE_KEY"])

result = client.tides.now(lat=-90, lon=-180, radius_km=100, hours=24)

print("endpoint:", result.endpoint)
print("cost:", result.cost_usd, "USDC")
print("tx:", (result.settlement or {}).get("tx_hash"))
print("data:", result.data)

MCP — Claude Desktop / AgentKit / any MCP hostjson

// 1. Add @2sio/mcp to your MCP host config (Claude Desktop example below).
//    EVM_PRIVATE_KEY funds x402 payments per call.

// claude_desktop_config.json
{
  "mcpServers": {
    "2sio": {
      "command": "npx",
      "args": ["-y", "@2sio/mcp"],
      "env": { "EVM_PRIVATE_KEY": "0x..." }
    }
  }
}

// 2. Once the server is running, agents call this tool via standard MCP:

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "tides.now",
    "arguments": {
      "lat": -90,
      "lon": -180,
      "radius_km": 100,
      "hours": 24
    }
  }
}

Discovery

/api/directory — full catalog of every endpoint
/openapi.json — OpenAPI 3.1 spec (per-op x-payment-info, x402Payment security)
/.well-known/x402 — machine-readable service descriptor for x402-aware crawlers
/.well-known/mcp/server-card.json — MCP SEP-1649 server card
/llms.txt — plain-text manifest for LLM ingestion

2s.io is x402-native. Every call is paid per-request from a USDC-funded EVM wallet on Base — no signup, no API keys, no monthly fees. Source code: github.com/2s-io/sdk.