Kylie Jenner and Travis Scott recently celebrated daughter Stormi’s third birthday together

Kylie Jenner and Travis Scott are going strong in their co-parenting relationship

The pair, who split in 2019 and share 3-year-old daughter Stormi Webster, "spend a lot of time together" but are not a couple, a source tells PEOPLE. They recently celebrated Stormi's birthday together along with family.

"In Kylie's eyes, the birthday party was toned down compared to last year. Only the cousins celebrated Stormi," the source says. "It was a small celebration. Stormi had the best time with her cousins."

The insider adds that Scott, 28, joined in on the celebration with a few of his friends, all of whom got tested for COVID-19 prior to the birthday bash. 

Travis Scott and Kylie Jenner
Travis Scott and Kylie Jenner
| Credit: Kevin Mazur/Getty

"He and Kylie are great co-parents," the source says of the former couple. "They share custody, but also spend a lot of time together with Stormi."

In addition to celebrating in person, both Jenner, 23, and Scott shared Instagram tributes in honor of Stormi's birthday.

"Thank you God for sending this little soul to me. crying today because i can't stop the time 🥺," Jenner wrote on Instagram, sharing several photos of Stormi from the last three years.

"It's all the little things i'll miss like your cute voice and our long talks on the potty. watching you experience everything for the very first time has been the best part of these last few years 🤍 but on the other side i'm excited to watch you grow into the most special girl i know you will be and all the amazing things i know you will do," the makeup mogul added. "Happy birthday to my baby forever!!!!"

Scott also posted on Instagram for his "Lil storm storm" on Monday, sharing a poem in his daughter's honor.

"3 is bigger than 2/ 3 more years of love that's true/ 3 more inches u might have grew/ 3 more years a lot to dooo!!!" he wrote. "3 more TIMES I LOVE UUUUUU/ Happy bday to my Lil storm storm."