Free · No key · Millions of requests / month

A fast, keyless API for the sun and the moon.

JSON sunrise, sunset, twilight, golden hour, and moon data for any point on Earth. No signup, no key, no rate limit dance. Just call it.

Request

GETapi.sunrisesunset.io/json?lat=38.9&lng=-77

fetch("https://api.sunrisesunset.io/json?lat=38.9&lng=-77")
  .then(r => r.json())
  .then(data => console.log(data.results.sunrise));

cURL

curl "https://api.sunrisesunset.io/json?lat=38.9&lng=-77"

Response200 OK

{
  "results": {
    "date": "2026-06-21",
    "sunrise": "5:43:05 AM",
    "sunset": "8:36:50 PM",
    "first_light": "3:42:17 AM",
    "last_light": "10:37:38 PM",
    "dawn": "5:10:24 AM",
    "dusk": "9:09:31 PM",
    "solar_noon": "1:09:58 PM",
    "golden_hour": "7:58:12 PM",
    "day_length": "14:53:45",
    "nautical_twilight_begin": "4:28:40 AM",
    "nautical_twilight_end": "9:51:15 PM",
    "timezone": "America/New_York",
    "utc_offset": -240,
    "sun_altitude": 72.58,
    "sun_azimuth": 180.27,
    "sunrise_azimuth": 58.14,
    "sunset_azimuth": 301.86,
    "moonrise": "1:16:23 PM",
    "moonset": "1:42:05 AM",
    "moon_illumination": 24.7,
    "moon_phase": "Waxing Crescent",
    "moon_phase_value": 0.22,
    "moon_always_up": false,
    "moon_always_down": false,
    "elevation": 26
  },
  "status": "OK",
  "tzid": "America/New_York"
}

Free forever

No signup, no API key, no credit card. Just include a link back to sunrisesunset.io.

Edge-served

Hosted on Cloudflare Workers in 300+ cities. P99 response times under 50 ms.

Up to 365 days

One request returns a full year of daily data via date_start + date_end.

Moon + sun

Rise, set, azimuth, altitude, and moon phase. All in one endpoint.

Example requests

All parameters

Parameters

All sent as query-string values on a single GET request.

latRequirednumber: Latitude in decimal degrees.
Example: 38.907192
lngRequirednumber: Longitude in decimal degrees.
Example: -77.036873
dateOptionalstring: Date to query. ISO YYYY-MM-DD, or a relative word like "today" or "tomorrow". Defaults to today in the location's timezone.
Example: 2026-06-21
date_startOptionalstring: Start of a date range (inclusive). Must be paired with date_end. Up to 365 days.
date_endOptionalstring: End of a date range (inclusive). Returns an array of daily results instead of a single object.
timezoneOptionalIANA tz: Return times in this timezone. Defaults to the location's IANA timezone resolved from lat/lng. Falls back silently if the value is invalid.
Default: auto
Example: America/New_York
time_formatOptionalenum: Format of all time fields. One of 12, 24, military, unix. Unix timestamps are always UTC.
Default: 12
formattedOptional0 | 1: Set to 0 to receive times in ISO 8601 format and day_length in seconds.
Default: 1
elevationOptionalnumber | false: Elevation override in meters. By default, auto-detected from terrain via ETOPO1. Pass false to compute at sea level. Higher elevation pushes sunrise earlier and sunset later.
Default: auto
callbackOptionalstring: JSONP callback function name. Returns application/javascript wrapped in your callback when present.

Response fields

Wrapped in { results, status, tzid }. results is a single object, or an array when a date range is used.

date: string; Queried date, YYYY-MM-DD.
sunrise: time; Sunrise time.
sunset: time; Sunset time.
dawn: time; Civil dawn — sun 6° below horizon in the morning.
dusk: time; Civil dusk — sun 6° below horizon in the evening.
first_light: time; Astronomical dawn — faintest sky brightening.
last_light: time; Astronomical dusk — last trace of sky light.
nautical_twilight_begin: time; Sun 12° below horizon in the morning.
nautical_twilight_end: time; Sun 12° below horizon in the evening.
solar_noon: time; Sun at its highest point.
golden_hour: time; Start of evening golden hour.
day_length: H:MM:SS | seconds; Length of daylight (seconds if formatted=0).
timezone: string; IANA timezone of the response times.
utc_offset: number; UTC offset in minutes.
sun_altitude: degrees; Sun altitude at solar noon.
sun_azimuth: degrees; Sun azimuth at solar noon (N = 0°, clockwise).
sunrise_azimuth: degrees; Compass bearing where the sun rises.
sunset_azimuth: degrees; Compass bearing where the sun sets.
moonrise: time | null; Moonrise time. Null if the moon doesn't rise that day.
moonset: time | null; Moonset time. Null if the moon doesn't set that day.
moon_illumination: percent; Percent of the moon's disk illuminated, 0–100.
moon_phase: string; Named phase: New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Last Quarter, Waning Crescent.
moon_phase_value: 0–1; Continuous phase value — 0 and 1 are new, 0.5 is full.
moon_always_up: boolean; True at polar latitudes when the moon is circumpolar that day.
moon_always_down: boolean; True when the moon doesn't appear above the horizon.
elevation: meters; Terrain elevation used in the calculation.

Status codes

Returned in the status field. HTTP status follows logically — 200 for OK and INVALID_TZID (which still returns data), 400 for bad input, 500 for unexpected.

OKRequest succeeded.
INVALID_TZIDTimezone parameter couldn't be validated; we fell back to the location's timezone and still returned data.
INVALID_REQUESTMissing or malformed lat/lng.
INVALID_DATEUnparseable date, or a range longer than one year.
UNKNOWN_ERRORSomething went wrong on our end. Retry.

Attribution

The API is free for personal and commercial use. All we ask is a visible backlink. Paste this anywhere on your site:

Powered by <a href="https://sunrisesunset.io">SunriseSunset.io</a>

FAQ

Do I need an API key?: No — the keyless endpoint works for most apps. If you want higher limits or want to track usage per-app, sign in and mint a key in your account. When you do use a key, send it as Authorization: Bearer sss_.... Never put it in the URL query string — query strings get logged by every proxy and CDN on the wire.
Is it really free for commercial use?: Yes. A link back to sunrisesunset.io keeps the lights on — please include one on your site or in your attribution section.
How accurate are the times?: Astronomical to the second. Atmospheric refraction and terrain elevation are both factored in by default.
What if the sun or moon never rises/sets that day?: Fields return null. For the moon, moon_always_up or moon_always_down flip to true at polar latitudes.
Can I bulk-query a full year?: Yes. Use date_start and date_end (up to 365 days apart). You get an array of daily objects in one request.
What timezone are the times in?: Whatever the location is in, auto-detected from lat/lng. Override with the timezone parameter.
Rate limits?: None enforced. Be reasonable. If you're going to hit it every hour per user, cache on your end.

Changelog

Apr 4, 2026
Moon data (rise/set, phase, illumination), sun altitude/azimuth at solar noon + rise + set, automatic elevation from terrain.
Jan 14, 2026
JSONP callback, formatted=0 for ISO 8601 output, nautical twilight fields, granular status codes.
Apr 13, 2025
Fixed a DST edge-case that could return the wrong day at the boundary.
Jul 30, 2024
time_format option (12, 24, military, unix).
Nov 29, 2023
date_start + date_end range queries, up to 365 days.
Oct 13, 2023
Lower response times; migrated onto Cloudflare Workers.
May 26, 2023
utc_offset added to responses.
Jun 21, 2022
first_light + last_light fields (astronomical twilight).
Jun 9, 2022
API released.

Watching the API? Status page