From their website (https://mightyswell.com/faq/, retrieved May 2020)
"IS MIGHTY SWELL GLUTEN-FREE AND VEGAN-FRIENDLY?
"Yes! Mighty Swell is made with gluten-free and vegan-friendly ingredients."
Mighty Swell Head Over Heels Watermelon Mint Spiked Spritzer
Vegan
This product is listed as vegan friendly.
What the company told us
Correspondence on record, with the date of each entry.