The group API lets you read and create Facebook group data on behalf of group members.
If a group administrator installs your app in a group, you can both get access to group content, such as posts, photos, and videos, and post info to the group.
With Official Graph API, you can get information about a single group object, namely id and name of the group, cover and icon, description, member count, etc.
Access to public and private groups requires a user access token, to secret groups - a group administrator access token.
If you want to get the data of group members, you need permission
groups_access_member_info. Administrators can also let you grab group members' public info if they would like to share their public information with your app in the group.
Our Facebook API ensures you with any public groups data. You can get such profile group info as id, username, full name, biography (about), group photo URL, phone, current city, categories, language, member count, etc.