How can I see if there's new daily data available?

You can find the latest date of available data before you start calling endpoints by using the “Describe” endpoint. This endpoint does not cost any hits.  

https://api.similarweb.com/v1/website/bbc.com/traffic-and-engagement/describe

You’ll find the last available date under ‘response/traffic_and_engagement/countries/world/fresh_data’

{   

"response": {

       "traffic_and_engagement": {

           "countries": {               

"world": {                   

"start_date": "2020-08",                   

"end_date": "2021-07",                   

"fresh_data": "2021-08-14"               

}           

}       

}   

}

}

In the example above, the 14th August 2021 is the last day (included) for which you would get data if you retrieve the information for the last 28 days - see example response below.

   {
   "meta": {
       "request": {
           "granularity": "Daily",
           "main_domain_only": false,
           "mtd": false,
           "show_verified": false,
           "state": "",
           "page": null,
           "format": "json",
           "domain": "bbc.com",
           "start_date": null,
           "end_date": null,
           "country": "gb"
       },
       "status": "Success",
       "last_updated": "2021-08-14",
       "device": "Desktop"
   },
   "visits": [
       {
           "date": "2021-07-18",
           "visits": 430491.22956131917
       },
       {
           "date": "2021-07-19",
           "visits": 523352.88345673314
       },
       {
           "date": "2021-07-20",
           "visits": 498277.03826221765
       },
     (...)
       {
           "date": "2021-08-14",
           "visits": 388971.5990286701
       }
   ]
}

To subscribe to notifications via the API to be automatically updated when new daily and monthly data becomes available, please refer to this article.