Moneydance only supports automatic downloads using Direct Connect, and unfortunately Betterment doesn't support this connection method. If they begin to support Direct Connect at any point, we'd be happy to establish a connection with them.
Betterment uses other connection methods that Moneydance does not support, called Web Connect and Express Web Connect.
By only using Direct Connect, we can guarantee that your username, password and financial data only ever exists with your bank or on your own personal computer, and at no point are your details stored on another server.
You can read more about why we only support this connection type in our blog and also in this article.
Without Direct Connect, you are still able to easily import your data into the program. The best way to get your transactions into Moneydance is to use a web browser to download files from your bank's web site.
We'd recommend you download using the OFX or QFX file format if available. If not, use the QIF file format. (These files are sometimes referred to as Quicken or MS Money files). You can import the files to Moneydance using File --> Import.
The steps for manually importing your data are outlined in this article from the knowledge base.
Moneydance 2019 includes en embedded browser (currently a beta feature) that makes downloading from the banks website much easier. We're also working on another feature (coming soon) that will remember how you download from the banks site and help to automate the manual import process.
Hopefully this information is useful. If you have any other questions please let us know.