The X API v2 endpoints are equipped with a set of parameters called fields, which allows you to select just the data that you want from each of the objects in your endpoint response. By default, the Post object only returns the id and the text fields, and for Posts created since September 29, 2022, the edit_history_tweet_ids field. If you need the Post’s created date or public metrics, you will need to use the tweet.fields parameters to request them. This provides a higher degree of customization by enabling you to only request the fields you require depending on your use case. For example, you would include this query string in your request: ?tweet.fields=created_at,public_metrics Each object has its own parameter which is used to specifically request the fields that are associated with that object. Here are the different fields parameters that are currently available:
  • Post → tweet.fields
  • User → user.fields
  • Media → media.fields
  • Poll → poll.fields
  • Place → place.fields
When using an endpoint that primarily returns a particular object, simply use the matching field parameter and specify the field(s) desired in a comma-separated list as the value to that parameter to retrieve those fields in the response.

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Example

If you are using the GET /tweets/search/recent endpoint, you will primarily receive Tweet objects in that response. Without specifying any fields parameters, you will just receive the default values, id and text. If you are interested in receiving the public metrics of the Posts that are returned in the response, you will want to include the tweet.fields parameter in your request, with public_metrics set as the value. This request would look like the following. If you would like to use this request, make sure to replace $BEARER_TOKEN with your Bearer Token and send it using your command line tool. 
curl --request GET \
  --url 'https://api.x.com/2/tweets/search/recent?query=from%3Atwitterdev&tweet.fields=public_metrics' \
  --header 'Authorization: Bearer $BEARER_TOKEN'
If you send this request in your terminal, then each of the Posts that return will include the following fields: 
{
   "data": {
       "id": "1263150595717730305",
       "public_metrics": {
           "retweet_count": 12,
           "reply_count": 14,
           "like_count": 49,
           "quote_count": 7
       },
       "text": "Do you 👀our new Tweet settings?\n\nWe want to know how and why you’d use a feature like this in the API. Get the details and let us know what you think👇\nhttps://t.co/RtMhhfAcIB https://t.co/8wxeZ9fJER"
   }
}
If you would like to retrieve a set of fields from a secondary object that is associated with the primary object returned by an endpoint, you will need to include an additional expansions parameter. For example, if you were using the same GET search/tweets/recent endpoint as earlier, and you wanted to retrieve the author’s profile description, you will have to pass the expansions=author_id and user.fields=description with your request. Here is an example of what this might look like. If you would like to try this request, make sure to replace the $BEARER_TOKEN with your Bearer Token before pasting it into your command line tool. 
  curl --request GET \
  --url 'https://api.x.com/2/tweets/search/recent?query=from%3Atwitterdev&tweet.fields=public_metrics&expansions=author_id&user.fields=description' \
  --header 'Authorization: Bearer $BEARER_TOKEN'
If you specify this in the request, then each of the Posts that deliver will have the following fields, and the related user object’s default and specified fields will return within includes. The user object can be mapped back to the corresponding Post(s) by matching the tweet.author_id and users.id fields. 
{
  "data": [
    {
      "id": "1263150595717730305",
      "author_id": "2244994945",
      "text": "Do you 👀our new Tweet settings?\n\nWe want to know how and why you’d use a feature like this in the API. Get the details and let us know what you think👇\nhttps://t.co/RtMhhfAcIB https://t.co/8wxeZ9fJER",
      "public_metrics": {
        "retweet_count": 12,
        "reply_count": 13,
        "like_count": 51,
        "quote_count": 7
      }
    }
  ],
  "includes": {
    "users": [
      {
        "id": "2244994945",
        "username": "TwitterDev",
        "description": "The voice of the #TwitterDev team and your official source for updates, news, and events, related to the #TwitterAPI.",
        "name": "Twitter Dev"
      }
    ]
  }
}
Bear in mind that you cannot request specific subfields (for example, public_metrics.retweet_count). All subfields will be returned when the top-level field (public_metrics) is specified. We have listed all possible fields that you can request in each endpoints’ API reference page’s parameters table.  A full list of fields are listed in the object model. To expand and request fields on an object that is not that endpoint’s primary resource, use the expansions parameter with fields.