Jessica Davis is the protagonist of The Soulmate Equation, which is told from her third-person perspective (with the exception of the Epilogue). At the start of the book, Jess is 29 and works as a freelance statistician. She is described by River, her love interest, as “responsible, smart, conscientious” and “Bossy” (144). She struggles to navigate life as a young single mother to her daughter, Juno—particularly due to her strained relationship with her own mother, Jamie. Because Jess strives to make her grandparents Pops and Nana Jo (the people who raised her) and daughter Juno a priority, she has put romance on the backburner—until matching with River on his matchmaking platform DNADuo. Despite Jess’s initial hostility towards River and their match, she finds herself falling in love with him. In the process, she gains confidence and becomes a better granddaughter, mother, friend, and partner.

Dr. River Peña is the founder of GeneticAlly (the company behind matchmaking service DNADuo) and Jess’s love interest. River is in his mid-thirties and described as handsome. At the start of the book, Jess and Fizzy refer to him as “Americano” (7)—it being his regular order at the coffee shop Twiggs.