Preheat the oven to 350 degrees. Prepare a large baking sheet with parchment paper.

In a large mixing bowl, beat butter, sugar, and brown sugar until light and fluffy. Add the eggs and vanilla, beating for an additional 2 minutes.

Dissolve baking soda in hot water. Add to the batter.

Add in the flour and salt, mixing until well blended.

Fold the rainbow chips into the batter.

Using a cookie scoop, portion the dough and drop on the prepared baking sheet.

Bake for 8 to 10 minutes or until the edges are set. Remove the cookies from the oven but allow the cookies to rest for about 2 minutes on the baking sheet before transferring them to a wire rack to cool completely.

Store in an airtight container at room temperature for up to one week.