---
title: "Unbuilt residential floor area by city block in one postal code area"
method: GET
path: "/api/v1/postal-codes/{postalCode}/reserve-blocks"
tags: ["Areas"]
---

# Unbuilt residential floor area by city block in one postal code area

`GET /api/v1/postal-codes/{postalCode}/reserve-blocks`

## Request

- Base URL: `https://suomiatlas.com`
- URL: `https://suomiatlas.com/api/v1/postal-codes/{postalCode}/reserve-blocks`
- Auth: one of:
  - none
  - HTTP bearer

The city blocks of the Helsinki capital region (Helsinki, Espoo, Vantaa, Kauniainen) that still have unbuilt residential floor area in valid detailed plans, from HSY's SeutuRAMAVA by block (via Helsinki Region Infoshare, CC BY 4.0). Floor areas are m² of building rights (`k-m²`): `residential` is the apartment-block plus the small-house reserve. Each block is placed whole, unclipped, in the postal area that holds its interior point (a block on land reclaimed beyond the areas' shoreline goes to the nearest capital-region area within 500 m), so an area's blocks need not add up exactly to its `hri_reserve_residential` figure.

`registerDate` is the block release's plan-register date and `postalRegisterDate` that of the per-postal-code figures; `aligned` is true when they are the same release, and only then do the blocks explain the figure beside them. `registerDate` is null when no block release is loaded. An area outside the capital region returns an empty `blocks` array; an unknown code 404. Cached for an hour.

Example request: https://suomiatlas.com/api/v1/postal-codes/00700/reserve-blocks

## Path parameters

- `postalCode` string, required

## Response `200`

The area's blocks with unbuilt residential floor area.

- ReserveBlocks
  - `registerDate` string, date, nullable, required: The block release's register date; null when none is loaded.
  - `postalRegisterDate` string, date, nullable, required
  - `retrievedAt` string, date-time, nullable, required
  - `aligned` boolean, required: Both dates are the same release.
  - `blocks` ReserveBlock[], required
    - `blockId` string, required: HSY block id (korttunnus).
    - `residential` number, required: Unbuilt residential floor area, m².
    - `apartmentBlock` number, nullable, required
    - `smallHouse` number, nullable, required
    - `total` number, nullable, required: Unbuilt floor area of every use, m².
    - `underConstruction` number, nullable, required: Residential floor area under construction, m².
    - `geometry` object, required: GeoJSON Polygon or MultiPolygon, EPSG:4326.

## Other responses

- `404`: No such place, or no data for it. Also what a non-numeric `year` produces, because query-parameter conversion fails before the operation runs.

---

[API](https://skmtc.dev/suomiatlas/apis/suomiatlas-read-api.md) · [All operations](https://skmtc.dev/suomiatlas/apis/suomiatlas-read-api/llms.txt) · [OpenAPI document](https://skmtc.dev/suomiatlas/apis/suomiatlas-read-api/revisions/b2627414938d?raw)