Kyson and Bryson, four, and Leyton and Logan, three, died when the fire broke out in Sutton, south London, last night just before 7 p.m.
A 27-year-old woman has been arrested on suspicion of child neglect.
Despite the blaze, brave firefighters rushed inside and rescued the little ones before giving them CPR on the street outside until paramedics arrived.
Tragically, all four children were pronounced dead when they were taken to hospital.
Speaking at the scene, Deputy Fire Chief Richard Mills said: “When we arrived there were only the four children we rescued. ”
Their devastated mother, Deveca Rose, was reportedly absent when the “intense” hell ravaged the entire ground floor.
A neighbor claimed Deveca lived alone with her boys and worked as a nurse’s aide for the NHS.
The boys’ grandfather Jason Hoath paid a heartbreaking tribute to his grandsons.
He wrote on Facebook: “I am devastated to say that the horrific house fire that took place in Sutton last night and four children lost their lives were my amazing, smart and beautiful grandsons.”
“Kyson and Bryson, four, and Leyton and Logan, three, were taken too soon, they will always be in our hearts and thoughts.
“Boys, I love you forever.
A neighbor said: “Everyone has been really nice. We used to see mom in her twenties in the morning.
The boys went to the same school as mine which is Westbourne Primary School.
“The kids looked really happy. The boys looked really adorable and nothing seemed to be down.
“I didn’t know them personally. I only saw their mom in the morning.
“Everyone on this street knew them and the boys were really cute. ”