Moon phase API: illumination, age and next new and full moon

$0.01 per call · failed calls are never charged · no account or subscription: pay per call with a card key or USDC

Moon phase name, illuminated percentage and age in days for any date, plus the next new and full moon (UTC). Computed locally from the mean synodic month. Use for calendars and night-sky planning.

When to use it

Run it free (25 free calls) Buy credits by card (from $1) Example result (JSON)

Try it with your own inputs

Date or ISO time (default now)

Uses one of your 25 free calls. Nothing is charged, and a call that fails is not counted.

Inputs

NameTypeDescription
datestringDate or ISO time (default now)

Request

Over HTTP, with a card key from /credits:

curl -H "Authorization: Bearer adt_…" "https://tools.funwords.eu/moon?date=2026-10-18"

Or one of your 25 free calls, no key:

curl "https://tools.funwords.eu/moon?date=2026-10-18&trial=1"

Without a key, the same URL answers 402 Payment Required with x402 and MPP terms, so an agent with a wallet pays per call in USDC (Base, Polygon, Arbitrum or Solana over x402; Base or Tempo over MPP) and retries.

Example result

{
  "date": "2026-10-18",
  "phase": "Waning Crescent",
  "illuminationPercent": 12.4,
  "ageDays": 26.3,
  "nextNewMoon": "2026-10-21T…",
  "nextFullMoon": "2026-11-05T…"
}

From an AI agent (MCP)

Add the MCP server to Claude, Cursor or any MCP client. This tool is moon, and the first 25 successful calls are free:

https://tools.funwords.eu/mcp

Questions

Is it computed or looked up?

Computed locally from the mean synodic month.

How do I pay?

Each successful call costs $0.01; failed calls are not charged. The first 25 calls are free. Then pay with card credits (from $1; the key goes in an Authorization header or, for clients that can only fetch a URL, as api_key= in the URL) or per call in USDC over x402 or MPP. No account is needed.

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