Kaylee-Jayde Priest was found dead at a flat in Kingshurt, Solihull, where she lived with her mother, Nicola Priest, on August 9 last year.
Priest, aged 23, and her boyfriend 22-year-old Callum Redfern, from Dudley, were both convicted of manslaughter on Thursday at Birmingham Crown Court.
Debbie Windmill, Nicola's mother and Kaylee-Jayde's grandmother, has said the impact of the girl's death would live with her for the rest of her life.
She said in a statement after the verdicts: “I could never stop staring at the smile on her beautiful face.
"I loved every moment watching her develop to nearly school age; preparing to buy my first grandchild her pre-school uniform was something that filled me with such happiness.
"I couldn’t wait to see her in it, but this opportunity was stolen from me in the most brutal of ways.
"Everybody deserves the gift of life. Kaylee-Jayde deserved to show the world who she could have been and what greatness she could have brought to this world. Nanny will forever hold you in her heart."
Jurors in the trial were shown CCTV footage which captured the final moments of the "happy" three-year-old girl who was seen with her mother hours before she was killed.
The footage showed the girl and her mother using a lift at the block of flats, hours before the youngster's death. It showcased Priest’s total disinterest in her daughter; repeatedly checking her reflection in the mirror and scrolling through her phone, while the youngster periodically gazed up at her mother’s face.
#KayleeJayde | These are the final moments of tragic toddler Kaylee-Jayde Priest who was beaten to death in her own home.— West Midlands Police (@WMPolice) August 6, 2021
Her mum Nicola Priest and ex-partner Callum Redfern have today been jailed for 15 and 14 years respectively for her manslaughter.
RIP Kaylee-Jayde x pic.twitter.com/qFINubAKYv
At no point in the footage was there any physical contact between the pair, with Priest neglecting even to reach out to hold her daughter’s hand.
Detective Inspector Adam Jobson, from West Midlands Police, said it was unlikely the exact details of what happened on the day Kaylee-Jayde died will ever be revealed.
He said: “This was a heartbreaking case in which an innocent child has experienced terrible suffering at the hands of those who should be caring for her.
“On the night of the assault they were excited to see each other: their focus was on each other.
"The prosecution case was that Kaylee-Jayde was calling out for their attention, she wanted to carry on playing, and they lashed out in frustration.
“There was evidence of past, partially-healed injuries on Kaylee-Jayde’s body.
"We believe the level of discipline she was subjected to became increasingly forceful and violent during Priest and Redfern’s relationship, culminating in the fatal assault.
“Throughout our investigation we strived to find out exactly how and why Kaylee-Jayde Priest died… sadly it will only ever be Priest and Redfern who know the exact sequence of events that day.
“One thing is clear, Nicky Priest has failed her daughter, she’s failed to protect her and she should be - being a mother to that little girl - the one person who should have been able to protect her.
“My heart goes out to the family of Kaylee-Jayde who loved this little girl and had no idea of the suffering she was enduring.
“I would like to thank our detectives, in-particular DS Naomi Mauchan and our family liaison officers, who worked tirelessly over the last 12 months on this harrowing investigation, with the sole aim of securing justice for Kaylee-Jayde.”
Priest, of Poplar Avenue, Edgbaston, Birmingham, and Redfern, of Temple Street, Dudley, were sentenced at Birmingham Crown Court on Friday.