Free electricity price API

Quick start

Each request returns one day for one price area. Today's prices for SE3 (Stockholm):

curl https://spotwatts.com/api/v1/se3/today.json

A real response, shortened. The full response lists every interval of the day (96 quarters; 92 or 100 on the days the clocks change) and every hour.

{
    "zone": "SE3",
    "country": "SE",
    "timezone": "Europe/Stockholm",
    "currency": "SEK",
    "unit": "SEK/kWh",
    "date": "2026-10-26",
    "vat_rate": 25.0,
    "exchange_rate": {
        "eur": 11.131,
        "date": "2026-10-23"
    },
    "resolution": 15,
    "average": {
        "price": 0.11547,
        "price_vat": 0.14434,
        "eur_mwh": 10.37
    },
    "min": {
        "start": "2026-10-26T06:15:00+01:00",
        "end": "2026-10-26T06:30:00+01:00",
        "price": -0.0197,
        "price_vat": -0.02463,
        "eur_mwh": -1.77
    },
    "max": {
        "start": "2026-10-26T19:00:00+01:00",
        "end": "2026-10-26T19:15:00+01:00",
        "price": 0.48286,
        "price_vat": 0.60358,
        "eur_mwh": 43.38
    },
    "cheapest_windows": [
        {
            "hours": 1,
            "start": "2026-10-26T05:45:00+01:00",
            "end": "2026-10-26T06:45:00+01:00",
            "price": -0.00637,
            "price_vat": -0.00797,
            "eur_mwh": -0.57
        }
    ],
    "intervals": [
        {
            "start": "2026-10-26T00:00:00+01:00",
            "end": "2026-10-26T00:15:00+01:00",
            "price": 0.0108,
            "price_vat": 0.0135,
            "eur_mwh": 0.97
        },
        {
            "start": "2026-10-26T00:15:00+01:00",
            "end": "2026-10-26T00:30:00+01:00",
            "price": 0.00367,
            "price_vat": 0.00459,
            "eur_mwh": 0.33
        }
    ],
    "hours": [
        {
            "start": "2026-10-26T00:00:00+01:00",
            "end": "2026-10-26T01:00:00+01:00",
            "price": 0.00632,
            "price_vat": 0.0079,
            "eur_mwh": 0.57
        },
        {
            "start": "2026-10-26T01:00:00+01:00",
            "end": "2026-10-26T02:00:00+01:00",
            "price": 0.00331,
            "price_vat": 0.00414,
            "eur_mwh": 0.3
        }
    ],
    "page": "https://spotwatts.com/se/se3",
    "source": "ENTSO-E Transparency Platform",
    "attribution": {
        "text": "Prices: Spotwatts",
        "url": "https://spotwatts.com/"
    }
}

Endpoints

All addresses are plain paths under https://spotwatts.com/api/v1: no query parameters, no key. Responses are JSON in UTF-8.

Price area codes: no1–no5, se1–se4, dk1, dk2, fi, ee, lv, lt (lower case in the examples; upper case works too).

What a day contains

Price areas

When prices are updated

Tomorrow's prices come from the day-ahead auction and are published around 12:45–13:00 CET (13:45–14:00 Finnish and Baltic time). We check every five minutes, so they are here within minutes. Until then, tomorrow.json returns 404, which is not cached: try again later. Past days only change in the rare case of a correction.

Responses are cached, so the API is fast; please cache them on your side too. One IP address may send up to 60 requests per 10 seconds; above that, it gets 429 for 10 seconds. For day prices, one request per price area per hour is plenty.

Errors come with an HTTP status and a short reason in {"message": "…"}: 404 for an unknown price area or date, or a day that is not published yet; 429 when the limit above is reached (try again after 10 seconds).

Examples

JavaScript

const response = await fetch('https://spotwatts.com/api/v1/no1/today.json');
const day = await response.json();
for (const hour of day.hours) {
  console.log(hour.start, hour.price_vat, day.unit);
}

Python

import requests

url = 'https://spotwatts.com/api/v1/fi/today.json'
day = requests.get(url, timeout=10).json()
window = day['cheapest_windows'][2]  # 3 hours
print(window['start'], window['price_vat'], day['unit'])

Home Assistant

Two REST sensors (configuration.yaml): the current price including VAT, updated every 5 minutes, and today's average with the hourly prices and cheapest windows as attributes for charts and automations.

rest:
  - resource: "https://spotwatts.com/api/v1/se3/now.json"
    scan_interval: 300
    sensor:
      - name: Electricity price SE3
        value_template: "{{ value_json.price_vat }}"
        availability: "{{ value_json.price_vat is defined }}"
        unit_of_measurement: "SEK/kWh"
  - resource: "https://spotwatts.com/api/v1/se3/today.json"
    scan_interval: 3600
    sensor:
      - name: Electricity price SE3 today
        value_template: "{{ value_json.average.price_vat }}"
        availability: "{{ value_json.average is defined }}"
        unit_of_measurement: "SEK/kWh"
        json_attributes:
          - hours
          - cheapest_windows

Common daily-file format

Code written for the common daily-file format (one file per day and price area: an array of {currency}_per_kWh and EUR_per_kWh without VAT, EXR, time_start and time_end) works here too: use https://spotwatts.com/api/v1/prices/2026/10-25_SE3.json. There is one entry per interval, and the format is available for all 15 price areas.

Terms of use

You may use the prices for free, including in commercial apps, websites, dashboards and products.

Wherever you show the prices publicly, put a visible link to Spotwatts next to them with the text "Prices: Spotwatts", as below. Any rel value is fine, including rel="nofollow".

Copy this HTML:

<a href="https://spotwatts.com/">Prices: Spotwatts</a>

Fetch only the days you need. Do not download the whole history in bulk or mirror the API; cache what you have fetched. If you need more than a few months of history at once, contact us first.

The prices are day-ahead auction results from the ENTSO-E Transparency Platform. Spotwatts is not affiliated with or endorsed by ENTSO-E or Nord Pool.

The API is provided as is, with no guarantee that it is available or accurate. Do not use it for trading or anywhere an error could cause harm. Version 1 stays stable; any breaking change will come as /api/v2.

Questions or problems: contact us.