Toggl offers offers online time tracking and reporting services through a web interface and mobile and desktop applications.

Apache Superset is a cloud-native data exploration and visualization platform that businesses can use to create business intelligence reports and dashboards. It includes a state-of-the-art SQL IDE, and it's open source software, free of cost. The platform was originally developed at Airbnb and donated to the Apache Software Foundation.

Toggl has a couple of APIs that developers can use to interact with the platform. The Reports API lets you get information out. For example, to retrieve a summary report, you could call GET "https://toggl.com/reports/api/v2/summary?workspace_id=123&since=2018-12-19&until=2018-12-20&user_agent=api_test".

Here's an example of the kind of response you might see from a query like the one above.

{
    "total_grand":36004000,
    "total_billable":14400000,
    "total_currencies":[{"currency":"EUR","amount":40}],
    "data": [
      {
        "id":73569,
        "title":{"project":"Toggl Desktop","client":"Toggl"},
        "time":14400000,
        "total_currencies":[{"currency":"EUR","amount":40}],
        "items":[
          {
            "title":{"time_entry":"Implementing some important things"},
            "time":14400000,
            "cur":"EUR",
            "sum":40,
            "rate":10
          }
        ]
      },{
        "id":193009951,
        "title":{"project":"Toggl Development","client":null},
        "time":14400000,
        "total_currencies":[{"currency":"EUR","amount":0}],
        "items":[
          {
            "title":{"time_entry":"Hard work"},
            "time":14400000,
            "cur":"EUR",
            "sum":0,
            "rate":50
          }
        ]
      },{
        "id":null,
        "title":{"project":null,"client":null},
        "time":7204000,
        "total_currencies":[],
        "items":[
          {
            "title":{"time_entry":"No title yet"},
            "time":1000,
            "cur":"EUR",
            "sum":0,
            "rate":50
          },{
            "title":{"time_entry":"Did nothing"},
            "time":1000,
            "cur":"EUR",
            "sum":0,
            "rate":50
          },{
            "title":{"time_entry":"Hard work again"},
            "time":7202000,
            "cur":"EUR",
            "sum":0,
            "rate":50
          }
        ]
      }
    ]
  }

If you don't already have a data structure in which to store the data you retrieve, you'll have to create a schema for your data tables. Then, for each value in the response, you'll need to identify a predefined datatype (INTEGER, DATETIME, etc.) and build a table that can receive them. Toggl's documentation should tell you what fields are provided by each endpoint, along with their corresponding datatypes.

Complicating things is the fact that the records retrieved from the source may not always be "flat" – some of the objects may actually be lists. In these cases you'll likely have to create additional tables to capture the unpredictable cardinality in each record.

You must replicate data from your SaaS applications to a data warehouse before you can report on it using Superset. Superset can connect to almost 30 databases and data warehouses. Once you choose a data source you want to connect to, you must specify a host name and port, database name, and username and password to get access to the data. You then specify the database schema or tables you want to work with.

At this point you've coded up a script or written a program to get the data you want and successfully moved it into your data warehouse. But how will you load new or updated data? It's not a good idea to replicate all of your data each time you have updated records. That process would be painfully slow and resource-intensive.

The key is to build your script in such a way that it can identify incremental updates to your data, using datetime request parameters like since and until to identify records that are new since your last update (or since the newest record you've copied). Once you've take new data into account, you can set your script up as a cron job or continuous loop to keep pulling down new data as it appears.