JQuery get data from JSON array

You need to iterate both the groups and the items.
$.each() takes a collection as first parameter and data.response.venue.tips.
groups.items.text tries to point to a string. Both groups and items are arrays.

Verbose version:

$.getJSON(url, function (data) {

    // Iterate the groups first.
    $.each(data.response.venue.tips.groups, function (index, value) {

        // Get the items
        var items = this.items; // Here 'this' points to a 'group' in 'groups'

        // Iterate through items.
        $.each(items, function () {
            console.log(this.text); // Here 'this' points to an 'item' in 'items'
        });
    });
});

Or more simply

$.getJSON(url, function (data) {
    $.each(data.response.venue.tips.groups, function (index, value) {
        $.each(this.items, function () {
            console.log(this.text);
        });
    });
});