# Filters

Filtering allows you to narrow API results using specific conditions. You can filter resources by one or more attributes
using query parameters that start with `filter`.

This feature supports both simple and complex queries, including combining multiple conditions and using arrays.

Important

Filters are supported on any endpoint that responds with a resource collection.

---



## Filter by a single attribute

Use a single filter parameter to retrieve resources matching a specific value.

In this example, cities are filtered by their `country.id` and returns only cities within the specified country:

[[DIDWW-API-EXAMPLE-START]]

http

```
GET /v3/cities?filter%5Bcountry.id%5D=72f22218-ab1f-4933-a74d-a6467f3f6cb0 HTTP/1.1
Host: api.didww.com
Accept: application/vnd.api+json
```

curl

```
curl -i -X GET 'https://api.didww.com/v3/cities?filter%5Bcountry.id%5D=72f22218-ab1f-4933-a74d-a6467f3f6cb0' -H "Accept: application/vnd.api+json"
```

[[DIDWW-API-EXAMPLE-END]]

---

## Filter by multiple attributes

You can combine multiple filter parameters to refine results further.

In this example, cities are filtered by both `country.id` and `region.id`, and returns only cities that match both
conditions:

[[DIDWW-API-EXAMPLE-START]]

http

```
GET /v3/cities?filter%5Bcountry.id%5D=72f22218-ab1f-4933-a74d-a6467f3f6cb0&filter%5Bregion.id%5D=0800cac6-a0eb-4d58-8284-e5207b65a91b HTTP/1.1
Host: api.didww.com
Accept: application/vnd.api+json
```

curl

```
curl -i -X GET 'https://api.didww.com/v3/cities?filter%5Bcountry.id%5D=72f22218-ab1f-4933-a74d-a6467f3f6cb0&filter%5Bregion.id%5D=0800cac6-a0eb-4d58-8284-e5207b65a91b' -H "Accept: application/vnd.api+json"
```

[[DIDWW-API-EXAMPLE-END]]

---

## Filter by arrays

You can use arrays in filters by separating values with commas.

For example, to filter DIDs that support specified features such as voice, voice\_out, t38, sms, sms\_out:

```
filter[features]=voice,voice_out,t38,sms,sms_out
```

Important

Do **not** provide the same filter multiple times (e.g., `filter[features]=voice&filter[features]=sms`). Instead, use a
single filter with comma-separated values.

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