New version out now! Find it here: https://stardew.info/planner/

FAQ:

1. What is this?
This is Stardew Valley interactive farm planner
2. Where are sprites, why are there only colors?
As this is the very early version of farm planner, sprites are not yet supported
3. Saving doesn't appear to do anything?
When you press save, your farm layout is put into the URL. You can share and store the URL.
4. Does this work on touch devices (tablets, phones)?
Current version does not officially support touch devices yet but it is planned for future.
5. Not working? Having any issues?
Feel free to contact me in reddit or file an issue @ Github