STAC API

The Freva STAC (SpatioTemporal Asset Catalog) API provides a standardized way to access climate datasets following the STAC specification. STAC is an open standard for geospatial data cataloguing, enabling consistent discovery and access of climate datasets, satellite imagery and spatiotemporal data.

The STAC API allows you to:

• Browse collections of climate datasets

• Free text-search for specific data items across collections

• Access detailed metadata about datasets and their spatial/temporal coverage

• Use standardized filtering and pagination

• Integrate with STAC-compatible tools and libraries

Getting Started

The STAC API organizes data into Collections and Items:

• Collections: project search parameters (e.g., “observations”, “CMIP6”)

• Items: Individual dataset files with geospatial and temporal metadata

Authentication is not required for read-only access to the STAC API.

—

Landing Page

GET /api/freva-nextgen/stacapi/

Get the STAC API landing page which provides information about the API version, title, description, and links to collections and other resources. This serves as the entry point for exploring available collections and items.

Status Codes:

• 200 OK – STAC API landing page returned successfully

• 503 Service Unavailable – Search backend error

Response Headers:

• Content-Type – application/json

Example Request

GET /api/freva-nextgen/stacapi/ HTTP/1.1
Host: www.freva.dkrz.de

Example Response

HTTP/1.1 200 OK
Content-Type: application/json

{
    "type": "Catalog",
    "id": "freva",
    "title": "Freva STAC-API",
    "description": "FAIR data for the Freva",
    "stac_version": "1.1.0",
    "stac_extensions": ["https://api.stacspec.org/v1.0.0/core"],
    "conformsTo": [
        "https://api.stacspec.org/v1.0.0/core",
        "https://api.stacspec.org/v1.0.0/collections",
        "https://api.stacspec.org/v1.0.0/item-search"
    ],
    "links": [
        {
            "rel": "self",
            "href": "https://www.freva.dkrz.de/api/freva-nextgen/stacapi",
            "type": "application/json",
            "title": "Landing Page"
        },
        {
            "rel": "data",
            "href": "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections",
            "type": "application/json",
            "title": "Data Collections"
        }
    ]
}

Code examples

• Shell
• Python
• gnuR
• Julia
• C/C++

curl -X GET https://www.freva.dkrz.de/api/freva-nextgen/stacapi/

import requests
response = requests.get("https://www.freva.dkrz.de/api/freva-nextgen/stacapi/")
data = response.json()

library(httr)
response <- GET("https://www.freva.dkrz.de/api/freva-nextgen/stacapi/")
data <- jsonlite::fromJSON(content(response, as = "text", encoding = "utf-8"))

using HTTP, JSON
response = HTTP.get("https://www.freva.dkrz.de/api/freva-nextgen/stacapi/")
data = JSON.parse(String(HTTP.body(response)))

#include <stdio.h>
#include <curl/curl.h>

int main() {
    CURL *curl;
    CURLcode res;

    curl = curl_easy_init();
    if (curl) {
        char url[] = "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/";

        curl_easy_setopt(curl, CURLOPT_URL, url);
        res = curl_easy_perform(curl);
        curl_easy_cleanup(curl);
    }

    return 0;
}

—

Conformance Classes

GET /api/freva-nextgen/stacapi/conformance

Get the conformance classes that the STAC API implementation conforms to. This provides information about the supported features and capabilities of the API.

Status Codes:

• 200 OK – Conformance classes returned successfully

• 503 Service Unavailable – Search backend error

Response Headers:

• Content-Type – application/json

Example Request

GET /api/freva-nextgen/stacapi/conformance HTTP/1.1
Host: www.freva.dkrz.de

Example Response

HTTP/1.1 200 OK
Content-Type: application/json

{
    "conformsTo": [
        "https://api.stacspec.org/v1.0.0/core",
        "https://api.stacspec.org/v1.0.0/collections",
        "https://api.stacspec.org/v1.0.0/item-search"
    ]
}

Code examples

• Shell
• Python
• gnuR
• Julia
• C/C++

curl -X GET https://www.freva.dkrz.de/api/freva-nextgen/stacapi/conformance

import requests
response = requests.get("https://www.freva.dkrz.de/api/freva-nextgen/stacapi/conformance")
data = response.json()

library(httr)
response <- GET("https://www.freva.dkrz.de/api/freva-nextgen/stacapi/conformance")
data <- jsonlite::fromJSON(content(response, as = "text", encoding = "utf-8"))

using HTTP, JSON
response = HTTP.get("https://www.freva.dkrz.de/api/freva-nextgen/stacapi/conformance")
data = JSON.parse(String(HTTP.body(response)))

#include <stdio.h>
#include <curl/curl.h>

int main() {
    CURL *curl;
    CURLcode res;

    curl = curl_easy_init();
    if (curl) {
        char url[] = "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/conformance";

        curl_easy_setopt(curl, CURLOPT_URL, url);
        res = curl_easy_perform(curl);
        curl_easy_cleanup(curl);
    }

    return 0;
}

—

Collections

GET /api/freva-nextgen/stacapi/collections

List all collections available in the STAC API. Each collection represents a group of related items and provides metadata including ID, title, description, and spatial/temporal extents.

Status Codes:

• 200 OK – Collections list returned successfully

• 503 Service Unavailable – Search backend error

Response Headers:

• Content-Type – application/json

Example Request

GET /api/freva-nextgen/stacapi/collections HTTP/1.1
Host: www.freva.dkrz.de

Example Response

HTTP/1.1 200 OK
Content-Type: application/json

{
    "collections": [
        {
            "id": "observations",
            "type": "Collection",
            "stac_version": "1.1.0",
            "title": "OBSERVATIONS",
            "description": "Collection OBSERVATIONS",
            "license": "proprietary",
            "extent": {
                "spatial": {"bbox": [[-180, -90, 180, 90]]},
                "temporal": {"interval": [[null, null]]}
            },
            "links": [
                {
                    "rel": "items",
                    "href": "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections/observations/items",
                    "type": "application/geo+json",
                    "title": "Items"
                }
            ]
        }
    ]
}

Code examples

• Shell
• Python
• gnuR
• Julia
• C/C++

curl -X GET https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections

import requests
response = requests.get("https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections")
collections = response.json()["collections"]

library(httr)
response <- GET("https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections")
data <- jsonlite::fromJSON(content(response, as = "text", encoding = "utf-8"))
collections <- data$collections

using HTTP, JSON
response = HTTP.get("https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections")
data = JSON.parse(String(HTTP.body(response)))
collections = data["collections"]

#include <stdio.h>
#include <curl/curl.h>

int main() {
    CURL *curl;
    CURLcode res;

    curl = curl_easy_init();
    if (curl) {
        char url[] = "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections";

        curl_easy_setopt(curl, CURLOPT_URL, url);
        res = curl_easy_perform(curl);
        curl_easy_cleanup(curl);
    }

    return 0;
}

—

Get Collection

GET /api/freva-nextgen/stacapi/collections/(str: collection_id)

Get a specific collection by its ID. Returns detailed metadata about the collection including its extent, license, and available links.

Parameters:

• collection_id (str) – The unique identifier for the collection

Status Codes:

• 200 OK – Collection returned successfully

• 404 Not Found – Collection not found

• 503 Service Unavailable – Search backend error

Response Headers:

• Content-Type – application/json

Example Request

GET /api/freva-nextgen/stacapi/collections/observations HTTP/1.1
Host: www.freva.dkrz.de

Example Response

HTTP/1.1 200 OK
Content-Type: application/json

{
    "id": "observations",
    "type": "Collection",
    "stac_version": "1.1.0",
    "title": "OBSERVATIONS",
    "description": "Collection OBSERVATIONS",
    "license": "proprietary",
    "extent": {
        "spatial": {"bbox": [[-180, -90, 180, 90]]},
        "temporal": {"interval": [[null, null]]}
    },
    "links": [
        {
            "rel": "items",
            "href": "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections/observations/items",
            "type": "application/geo+json",
            "title": "Items"
        }
    ],
    "keywords": ["observations", "climate", "analysis", "freva"]
}

Code examples

• Shell
• Python
• gnuR
• Julia
• C/C++

curl -X GET https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections/observations

import requests
response = requests.get("https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections/observations")
collection = response.json()

library(httr)
response <- GET("https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections/observations")
collection <- jsonlite::fromJSON(content(response, as = "text", encoding = "utf-8"))

using HTTP, JSON
response = HTTP.get("https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections/observations")
collection = JSON.parse(String(HTTP.body(response)))

#include <stdio.h>
#include <curl/curl.h>

int main() {
    CURL *curl;
    CURLcode res;

    curl = curl_easy_init();
    if (curl) {
        char url[] = "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections/observations";

        curl_easy_setopt(curl, CURLOPT_URL, url);
        res = curl_easy_perform(curl);
        curl_easy_cleanup(curl);
    }

    return 0;
}

—

Get Collection Items

GET /api/freva-nextgen/stacapi/collections/(str: collection_id)/items

Get items from a specific collection. Items can be filtered using various query parameters such as limit, datetime range, and bounding box.

Parameters:

• collection_id (str) – The unique identifier for the collection

Query Parameters:

• limit – Maximum number of items to return (1-1000)

• token – Pagination token in format “direction:collection_id:item_id”

• datetime – Datetime range in RFC 3339 format (start-date/end-date or exact-date)

• bbox – Bounding box as “minx,miny,maxx,maxy”

Status Codes:

• 200 OK – Items returned successfully

• 422 Unprocessable Entity – Invalid query parameters

• 503 Service Unavailable – Search backend error

Response Headers:

• Content-Type – application/geo+json

Example Request

GET /api/freva-nextgen/stacapi/collections/observations/items?limit=2&bbox=-180,-90,180,90 HTTP/1.1
Host: www.freva.dkrz.de

Example Response

HTTP/1.1 200 OK
Content-Type: application/geo+json

{
    "type": "FeatureCollection",
    "features": [
        {
            "type": "Feature",
            "stac_version": "1.1.0",
            "id": "1834103571652542466",
            "geometry": {
                "type": "Polygon",
                "coordinates": [[[-180.0, -90.0], [180.0, -90.0], [180.0, 90.0], [-180.0, 90.0], [-180.0, -90.0]]]
            },
            "properties": {
                "variable": ["pr"],
                "experiment": ["cmorph"],
                "institute": ["CPC"],
                "datetime": "2016-09-02T23:00:00Z"
            },
            "collection": "observations",
            "bbox": [-180.0, -90.0, 180.0, 90.0]
        }
    ],
    "links": [
        {
            "rel": "self",
            "href": "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections/observations/items?limit=2",
            "type": "application/geo+json"
        },
        {
            "rel": "next",
            "href": "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections/observations/items?limit=2&token=next%3Aobservations%3A1834103571652542467",
            "type": "application/geo+json",
            "method": "GET"
        }
    ]
}

Code examples

• Shell
• Python
• gnuR
• Julia
• C/C++

curl -X GET \
'https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections/observations/items?limit=10&datetime=2016-01-01/2016-12-31'

import requests
response = requests.get(
    "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections/observations/items",
    params={
        "limit": 10,
        "datetime": "2016-01-01/2016-12-31",
        "bbox": "-10,40,10,60"
    }
)
items = response.json()

library(httr)
response <- GET(
    "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections/observations/items",
    query = list(
        limit = 10,
        datetime = "2016-01-01/2016-12-31",
        bbox = "-10,40,10,60"
    )
)
data <- jsonlite::fromJSON(content(response, as = "text", encoding = "utf-8"))

using HTTP, JSON
response = HTTP.get(
    "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections/observations/items",
    query = Dict(
        "limit" => 10,
        "datetime" => "2016-01-01/2016-12-31",
        "bbox" => "-10,40,10,60"
    )
)
data = JSON.parse(String(HTTP.body(response)))

#include <stdio.h>
#include <curl/curl.h>

int main() {
    CURL *curl;
    CURLcode res;

    curl = curl_easy_init();
    if (curl) {
        char url[] = "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections/observations/items?limit=10&datetime=2016-01-01/2016-12-31&bbox=-10,40,10,60";

        curl_easy_setopt(curl, CURLOPT_URL, url);
        res = curl_easy_perform(curl);
        curl_easy_cleanup(curl);
    }

    return 0;
}

—

Get Collection Item Details

GET /api/freva-nextgen/stacapi/collections/(str: collection_id)/items/(str: item_id)

Get a specific item from a collection. Returns detailed metadata about the dataset including its geometry, properties, assets, and links.

Parameters:

• collection_id (str) – The unique identifier for the collection

• item_id (str) – The unique identifier for the item

Status Codes:

• 200 OK – Item returned successfully

• 404 Not Found – Item not found

• 503 Service Unavailable – Search backend error

Response Headers:

• Content-Type – application/json

Example Request

GET /api/freva-nextgen/stacapi/collections/observations/items/1834103571652542466 HTTP/1.1
Host: www.freva.dkrz.de

Example Response

HTTP/1.1 200 OK
Content-Type: application/json

{
    "type": "Feature",
    "stac_version": "1.1.0",
    "id": "1834103571652542466",
    "geometry": {
        "type": "Polygon",
        "coordinates": [[[-180.0, -90.0], [180.0, -90.0], [180.0, 90.0], [-180.0, 90.0], [-180.0, -90.0]]]
    },
    "properties": {
        "variable": ["pr"],
        "experiment": ["cmorph"],
        "institute": ["CPC"],
        "datetime": "2016-09-02T23:00:00Z"
    },
    "collection": "observations",
    "bbox": [-180.0, -90.0, 180.0, 90.0],
    "assets": {
        "zarr-access": {
            "href": "https://www.freva.dkrz.de/api/freva-nextgen/databrowser/load/freva?file=/path/to/file.nc",
            "title": "Stream Zarr Data",
            "type": "application/vnd+zarr",
            "roles": ["data"]
        }
    }
}

Code examples

• Shell
• Python
• gnuR
• Julia
• C/C++

curl -X GET https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections/observations/items/1834103571652542466

import requests
response = requests.get("https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections/observations/items/1834103571652542466")
item = response.json()

library(httr)
response <- GET("https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections/observations/items/1834103571652542466")
item <- jsonlite::fromJSON(content(response, as = "text", encoding = "utf-8"))

using HTTP, JSON
response = HTTP.get("https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections/observations/items/1834103571652542466")
item = JSON.parse(String(HTTP.body(response)))

#include <stdio.h>
#include <curl/curl.h>

int main() {
    CURL *curl;
    CURLcode res;

    curl = curl_easy_init();
    if (curl) {
        char url[] = "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections/observations/items/1834103571652542466";

        curl_easy_setopt(curl, CURLOPT_URL, url);
        res = curl_easy_perform(curl);
        curl_easy_cleanup(curl);
    }

    return 0;
}

—

Search (GET)

GET /api/freva-nextgen/stacapi/search

Search for items across collections using query parameters. Supports spatial, temporal, and property-based filtering with free text search capabilities.

Query Parameters:

• collections – Comma-separated list of collection IDs to search

• ids – Comma-separated list of item IDs to search

• bbox – Bounding box as “minx,miny,maxx,maxy”

• datetime – Datetime range in RFC 3339 format

• limit – Maximum number of items to return (1-1000)

• token – Pagination token for next/previous pages

• q – Free text search query (comma-separated terms)

Status Codes:

• 200 OK – Search results returned successfully

• 422 Unprocessable Entity – Invalid query parameters

• 503 Service Unavailable – Search backend error

Response Headers:

• Content-Type – application/geo+json

Example Request

GET /api/freva-nextgen/stacapi/search?collections=observations&q=precipitation,temperature&limit=5 HTTP/1.1
Host: www.freva.dkrz.de

Example Response

HTTP/1.1 200 OK
Content-Type: application/geo+json

{
    "type": "FeatureCollection",
    "features": [
        {
            "type": "Feature",
            "stac_version": "1.1.0",
            "id": "1834103571652542466",
            "properties": {
                "variable": ["pr"],
                "experiment": ["cmorph"]
            },
            "collection": "observations"
        }
    ],
    "links": [
        {
            "rel": "self",
            "href": "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/search?collections=observations&q=precipitation&limit=5",
            "type": "application/geo+json"
        }
    ]
}

Code examples

• Shell
• Python
• gnuR
• Julia
• C/C++

curl -X GET \
'https://www.freva.dkrz.de/api/freva-nextgen/stacapi/search?collections=observations&q=temperature&bbox=-180,-90,180,90&limit=10'

import requests
response = requests.get(
    "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/search",
    params={
        "collections": "observations,cmip6",
        "q": "precipitation,temperature",
        "bbox": "-180,-90,180,90",
        "datetime": "2020-01-01/2020-12-31",
        "limit": 20
    }
)
results = response.json()

library(httr)
response <- GET(
    "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/search",
    query = list(
        collections = "observations",
        q = "temperature",
        bbox = "-180,-90,180,90",
        limit = 10
    )
)
data <- jsonlite::fromJSON(content(response, as = "text", encoding = "utf-8"))

using HTTP, JSON
response = HTTP.get(
    "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/search",
    query = Dict(
        "collections" => "observations",
        "q" => "temperature",
        "bbox" => "-180,-90,180,90",
        "limit" => 10
    )
)
data = JSON.parse(String(HTTP.body(response)))

#include <stdio.h>
#include <curl/curl.h>

int main() {
    CURL *curl;
    CURLcode res;

    curl = curl_easy_init();
    if (curl) {
        char url[] = "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/search?collections=observations&q=temperature&bbox=-180,-90,180,90&limit=10";

        curl_easy_setopt(curl, CURLOPT_URL, url);
        res = curl_easy_perform(curl);
        curl_easy_cleanup(curl);
    }

    return 0;
}

—

Search (POST)

POST /api/freva-nextgen/stacapi/search

Search for items across collections using a JSON request body. Provides the same functionality as the GET endpoint but allows for more complex search parameters and supports arrays for certain fields.

Reqbody collections:

List of collection IDs to search

Reqbody ids:

List of item IDs to search

Reqbody bbox:

Bounding box as [minx, miny, maxx, maxy]

Reqbody datetime:

Datetime range in RFC 3339 format

Reqbody limit:

Maximum number of items to return

Reqbody q:

Free text search terms (string or array)

Request Headers:

• Content-Type – application/json

Status Codes:

• 200 OK – Search results returned successfully

• 422 Unprocessable Entity – Invalid request body

• 503 Service Unavailable – Search backend error

Response Headers:

• Content-Type – application/geo+json

Example Request

POST /api/freva-nextgen/stacapi/search HTTP/1.1
Host: www.freva.dkrz.de
Content-Type: application/json

{
    "collections": ["observations", "cmip6"],
    "q": ["temperature", "precipitation"],
    "bbox": [-180, -90, 180, 90],
    "datetime": "2020-01-01/2020-12-31",
    "limit": 10
}

Code examples

• Shell
• Python
• gnuR
• Julia
• C/C++

curl -X POST \
'https://www.freva.dkrz.de/api/freva-nextgen/stacapi/search' \
-H "Content-Type: application/json" \
-d '{
    "collections": ["observations"],
    "q": ["temperature"],
    "limit": 10
}'

import requests
response = requests.post(
    "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/search",
    json={
        "collections": ["observations", "cmip6"],
        "q": ["temperature", "precipitation"],
        "bbox": [-180, -90, 180, 90],
        "datetime": "2020-01-01/2020-12-31",
        "limit": 20
    }
)
results = response.json()

library(httr)
response <- POST(
    "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/search",
    body = list(
        collections = list("observations"),
        q = list("temperature"),
        bbox = list(-180, -90, 180, 90),
        limit = 10
    ),
    encode = "json"
)
data <- jsonlite::fromJSON(content(response, as = "text", encoding = "utf-8"))

using HTTP, JSON
response = HTTP.post(
    "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/search",
    headers = Dict("Content-Type" => "application/json"),
    body = JSON.json(Dict(
        "collections" => ["observations"],
        "q" => ["temperature"],
        "bbox" => [-180, -90, 180, 90],
        "limit" => 10
    ))
)
data = JSON.parse(String(HTTP.body(response)))

#include <stdio.h>
#include <curl/curl.h>

int main() {
    CURL *curl;
    CURLcode res;

    const char *url = "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/search";
    const char *json_data = "{"
        "\"collections\": [\"observations\"],"
        "\"q\": [\"temperature\"],"
        "\"bbox\": [-180, -90, 180, 90],"
        "\"limit\": 10"
    "}";

    curl = curl_easy_init();
    if (curl) {
        struct curl_slist *headers = NULL;
        headers = curl_slist_append(headers, "Content-Type: application/json");

        curl_easy_setopt(curl, CURLOPT_URL, url);
        curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
        curl_easy_setopt(curl, CURLOPT_POST, 1L);
        curl_easy_setopt(curl, CURLOPT_POSTFIELDS, json_data);

        res = curl_easy_perform(curl);
        if (res != CURLE_OK) {
            fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
        }

        curl_slist_free_all(headers);
        curl_easy_cleanup(curl);
    }

    return 0;
}

—

Queryables

GET /api/freva-nextgen/stacapi/queryables

Get global queryables schema. Returns a JSON Schema document describing the properties that can be used in filter expressions across all collections.

Status Codes:

• 200 OK – Queryables schema returned successfully

• 503 Service Unavailable – Search backend error

Response Headers:

• Content-Type – application/schema+json

Example Request

GET /api/freva-nextgen/stacapi/queryables HTTP/1.1
Host: www.freva.dkrz.de

Example Response

HTTP/1.1 200 OK
Content-Type: application/schema+json

{
    "$schema": "https://json-schema.org/draft/2019-09/schema",
    "$id": "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/queryables",
    "type": "object",
    "title": "Queryables for Freva NextGen STAC API",
    "properties": {
        "id": {
            "description": "Item identifier",
            "type": "string"
        },
        "datetime": {
            "description": "Item datetime",
            "type": "string",
            "format": "date-time"
        },
        "variable": {
            "description": "Climate variable",
            "type": "string"
        }
    }
}

Code examples

• Shell
• Python
• gnuR
• Julia
• C/C++

curl -X GET https://www.freva.dkrz.de/api/freva-nextgen/stacapi/queryables

import requests
response = requests.get("https://www.freva.dkrz.de/api/freva-nextgen/stacapi/queryables")
queryables = response.json()

library(httr)
response <- GET("https://www.freva.dkrz.de/api/freva-nextgen/stacapi/queryables")
queryables <- jsonlite::fromJSON(content(response, as = "text", encoding = "utf-8"))

using HTTP, JSON
response = HTTP.get("https://www.freva.dkrz.de/api/freva-nextgen/stacapi/queryables")
queryables = JSON.parse(String(HTTP.body(response)))

#include <stdio.h>
#include <curl/curl.h>

int main() {
    CURL *curl;
    CURLcode res;

    curl = curl_easy_init();
    if (curl) {
        char url[] = "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/queryables";

        curl_easy_setopt(curl, CURLOPT_URL, url);
        res = curl_easy_perform(curl);
        curl_easy_cleanup(curl);
    }

    return 0;
}

—

Collection Queryables

GET /api/freva-nextgen/stacapi/collections/(str: collection_id)/queryables

Get collection-specific queryables schema. Returns a JSON Schema document describing the properties available for filtering items in a specific collection.

Parameters:

• collection_id (str) – The unique identifier for the collection

Status Codes:

• 200 OK – Collection queryables returned successfully

• 404 Not Found – Collection not found

• 503 Service Unavailable – Search backend error

Response Headers:

• Content-Type – application/schema+json

Example Request

GET /api/freva-nextgen/stacapi/collections/observations/queryables HTTP/1.1
Host: www.freva.dkrz.de

Code examples

• Shell
• Python
• gnuR
• Julia
• C/C++

curl -X GET https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections/observations/queryables

import requests
response = requests.get("https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections/observations/queryables")
queryables = response.json()

library(httr)
response <- GET("https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections/observations/queryables")
queryables <- jsonlite::fromJSON(content(response, as = "text", encoding = "utf-8"))

using HTTP, JSON
response = HTTP.get("https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections/observations/queryables")
queryables = JSON.parse(String(HTTP.body(response)))

#include <stdio.h>
#include <curl/curl.h>

int main() {
    CURL *curl;
    CURLcode res;

    curl = curl_easy_init();
    if (curl) {
        char url[] = "https://www.freva.dkrz.de/api/freva-nextgen/stacapi/collections/observations/queryables";

        curl_easy_setopt(curl, CURLOPT_URL, url);
        res = curl_easy_perform(curl);
        curl_easy_cleanup(curl);
    }

    return 0;
}

—

STAC-API Integration

The Freva STAC-API is fully compatible with STAC-compliant tools and libraries. You can use popular tools like:

• Python: pystac-client, pystac, stackstac

Integration Example with Python

• Python with pystac-client

from pystac_client import Client

# Connect to the Freva STAC API
catalog = Client.open("https://www.freva.dkrz.de/api/freva-nextgen/stacapi")

# Search for items
search = catalog.search(
    max_items=10,
    collections=["cmip6"],
    bbox=[-10, 40, 10, 60]
)

# Get items
items = list(search.items())
print(f"Found {len(items)} items")

—

Note

Please note that in these examples, “https://www.freva.dkrz.de” is used as a placeholder URL. You should replace it with the actual URL of your Freva STAC API instance.

Note

Free text search (q parameter) searches across relevant metadata fields including variable names, experiments, models, and institutes.

Important

Data transaction and ingestion into the Freva STAC-API is managed by administrators using the data-crawler tool. This has nothing to do with the STAC API itself, which is primarily focused on data discovery and access.