# Volton Public Data API

> Free, CC-BY-4.0 Estonian electricity-market data — JSON over HTTPS, hourly refresh.
> Sourced from Elering, Nord Pool, ENTSO-E via the Volton Liisa pipeline.

Site: https://public-data.volton.energy
OpenAPI 3.1 spec: https://public-data.volton.energy/openapi.yaml
Status: https://public-data.volton.energy/v1/_status.json

## URL pattern

- https://public-data.volton.energy/v1/{slug}/latest.json — rolling 7-day window, cached 60s.
  Includes today's partial data; this is the URL to use for "today".
- https://public-data.volton.energy/v1/{slug}/{YYYY-MM-DD}.json — immutable per-day archive
  (Europe/Tallinn local). Published the day after; today's and future
  dates return 403, not 404. Read /v1/_status.json's latest_archive_date
  to find the most recent fully-archived day.
- https://public-data.volton.energy/v1/_status.json — per-dataset last_refresh + health.
  Fetch this first to discover what's actually available.

## Datasets

- [Estonia mFRR clearing prices](https://public-data.volton.energy/mfrr-clearing-price/) — Manually-activated Frequency Restoration Reserve (mFRR) energy clearing prices for the Estonian bidding zone. One value per 15-minute Market Time Unit, per direction (up or down). Sourced from Elering and the Baltic Transparency Dashboard, refreshed hourly.
  - JSON: https://public-data.volton.energy/v1/mfrr-clearing-price/latest.json
  - Unit: EUR/MWh · Coverage: Estonia (EE bidding zone), from 2024-10-09

- [Estonia aFRR clearing prices](https://public-data.volton.energy/afrr-clearing-price/) — Automatically-activated Frequency Restoration Reserve (aFRR) energy clearing prices for the Estonian bidding zone. One value per 15-minute Market Time Unit, per direction (up or down). Sourced from Elering, refreshed hourly.
  - JSON: https://public-data.volton.energy/v1/afrr-clearing-price/latest.json
  - Unit: EUR/MWh · Coverage: Estonia (EE bidding zone), from 2025-04-15

- [Estonia mFRR capacity prices](https://public-data.volton.energy/mfrr-capacity-price/) — BBCM-cleared mFRR capacity availability prices for the Estonian bidding zone — what BSPs are paid for *being available*, separate from energy activation prices. One value per 15-minute MTU, per direction. Sourced from the Baltic Transparency Dashboard, refreshed hourly.
  - JSON: https://public-data.volton.energy/v1/mfrr-capacity-price/latest.json
  - Unit: EUR/MW/h · Coverage: Estonia (EE bidding zone), from 2025-02-04

- [Estonia aFRR capacity prices](https://public-data.volton.energy/afrr-capacity-price/) — BBCM-cleared aFRR capacity availability prices for the Estonian bidding zone — what BSPs are paid for *being available*, separate from energy activation prices. One value per 15-minute MTU, per direction. Sourced from the Baltic Transparency Dashboard; aFRR capacity procurement on BBCM started 15 April 2025.
  - JSON: https://public-data.volton.energy/v1/afrr-capacity-price/latest.json
  - Unit: EUR/MW/h · Coverage: Estonia (EE bidding zone), from 2025-04-15

- [Estonia imbalance price](https://public-data.volton.energy/imbalance-price/) — The single imbalance price settled with every Estonian Balance Responsible Party each 15-minute MTU. Derived from the marginal balancing-energy bids activated through MARI / PICASSO. Sourced from Elering, refreshed hourly.
  - JSON: https://public-data.volton.energy/v1/imbalance-price/latest.json
  - Unit: EUR/MWh · Coverage: Estonia (EE bidding zone), from 2024-10-09

- [Estonia day-ahead spot price](https://public-data.volton.energy/day-ahead-spot/) — The hourly day-ahead clearing price for the EE bidding zone, set by the SDAC pan-European auction at 13:00 CET each day. The reference price for nearly every Estonian electricity contract. Sourced from Nord Pool / ENTSO-E, refreshed hourly.
  - JSON: https://public-data.volton.energy/v1/day-ahead-spot/latest.json
  - Unit: EUR/MWh · Coverage: Estonia (EE bidding zone), from 2010-01-01

- [Estonia grid frequency](https://public-data.volton.energy/grid-frequency/) — Real-time AC frequency on the Estonian grid, which has been part of the Continental European Synchronous Area since 9 February 2025. The whole CESA shares one frequency in real time — Estonia and Portugal see the same number. Sourced from Elering, downsampled to 5-min mean and refreshed hourly.
  - JSON: https://public-data.volton.energy/v1/grid-frequency/latest.json
  - Unit: Hz · Coverage: Continental European Synchronous Area (Baltic LFC block), from 2025-02-09

## Citation

Volton Technology OÜ (2026). Volton Public Data API. CC-BY-4.0. https://public-data.volton.energy