---
title: "FREE re-verification calendar — derived window plus an optional recorded effective_to end"
method: GET
path: "/v1/calendar"
tags: ["Discovery", "Alerts"]
---

# FREE re-verification calendar — derived window plus an optional recorded effective_to end

`GET /v1/calendar`

## Request

- Base URL: `https://euroref.dev`
- URL: `https://euroref.dev/v1/calendar`
- Auth: none required

Free. Forward-looking companion to /v1/changes from stored fields only: reverify_by (our re-check cadence, not a government date) and next_effective_known when the served value has an end date; otherwise "unknown". A 402 here is a bug: do not pay.

## Query parameters

- `country` string
- `series` string

## Response `200`

Free and unmetered. price_note says so. Entries may mix status known and status unknown. Known copies current.effective_to into next_effective_known. Unknown omits next_effective_known and next_effective_basis. No payment headers.

- object
  - `as_of` string, date, required
  - `brand` string, required
  - `filters` object, required
    - `country` string, nullable
    - `series` string, nullable
  - `count` integer, required
  - `entries` object[], required: Sorted by country ascending, then series ascending.
    - `country` string, required: ISO 3166-1 alpha-2
    - `series` string, required
    - `name` string, required
    - `last_confirmed` string, date, required
    - `stale` boolean, required: Same rule as elsewhere: age in days since last_confirmed is greater than update_cycle_days.
    - `update_cycle_days` integer, required
    - `reverify_by` string, date, required: UTC calendar date of last_confirmed plus update_cycle_days. Service re-verification cadence, not a government announcement date.
    - `status` 'known' | 'unknown', required
    - `next_effective_known` string: Present only when status is known. Equals current.effective_to. Recorded end of the served value, not an invented MPC, budget, or wage-review date.
    - `next_effective_basis` 'effective_to': Present only when status is known.
  - `note` string, required: States that reverify_by is derived, that next_effective_known comes only from current.effective_to, and that notes prose is never parsed.
  - `price_note` string, required: States that this feed is free and unmetered, and points at GET /v1/changes for past moves. Series values remain paid at GET /v1/{country}/{series}.
  - `disclaimer` string, required

## Other responses

- `400`: Free. Malformed country (not two letters) or malformed series query. No payment.
- `404`: Free. Country is not in this brand's continent catalog. No payment.

---

[API](https://skmtc.dev/euroref/apis/euroref-european-government-reference-data.md) · [All operations](https://skmtc.dev/euroref/apis/euroref-european-government-reference-data/llms.txt) · [OpenAPI document](https://skmtc.dev/euroref/apis/euroref-european-government-reference-data/revisions/1c3a0bb74c77?raw)