Is Filmot's code open source?

No, the code behind Filmot is not open source.

If you want programmatic access to Filmot's data, Filmot offers a public, self-service API. Sign in, open API Keys, accept the Terms of Service and create a key. Each account can have up to five active keys. Every account has a monthly API credit allowance, and Patreon supporters receive larger allowances according to their tier. See the API documentation for details.