Fatima Khan, 20, added the caption: "This is what happens when you f*** with me" - but the knife attacker remains at large.
A woman who posted a Snapchat video of her boyfriend dying in a pool of blood has been found guilty of helping to arrange his killing.
Fatima Khan, 20, plotted with another man to kill Khalid Safi, 18, who she had been seeing for two years.
Mr Safi was knifed repeatedly in the chest by Raza Khan in North Acton, west London, on 1 December 2016, jurors at the Old Bailey were told.
As he lay dying, Khan posted a video on social media site Snapchat, with the caption: "This is what happens when you f*** with me."
Khan, a self-confessed Snapchat addict, said she was "ashamed" of the video but denied murder and alternative counts of manslaughter and conspiracy to cause GBH.
But, on a 10-1 majority verdict, the court found her guilty of manslaughter.
Jurors were shown the video of the stabbing and CCTV of the confrontation between the victim and love rival Raza Khan - wanted on suspicion of murder and whose whereabouts are unknown.
The court heard how the two men had fought over Fatima Khan a few years earlier, and that Mr Safi was injured in that incident.
Khan had been angered by the victim turning up at her home with a watch as a gift five days before the killing, because her family did not know about the relationship.
She threw the watch out of an upstairs window, prosecutor Kate Bex told the jury.
Ms Bex said Fatima Khan was "essential to the success of the plan" to get rid of Mr Safi.
"She told Raza Khan where to find Khalid Safi and she ensured Mr Safi was still there by the time Mr Khan travelled to the scene," the prosecutor said.
On the day of the killing, the victim and his girlfriend had gone to a Costa coffee shop near her work at Vigilant Security in North Acton.
Raza Khan arrived in a cab and immediately went up to the couple with a large knife in his hand, the court heard.
A few words were exchanged and Mr Safi pulled out a screwdriver. The pair then had a fight which lasted 15 seconds and was caught on CCTV.
"Mr Safi died at the scene having received a number of wounds to his chest, one penetrating his heart," said Ms Bex.
The attacker, 19, was injured in the fight, but calmly left the scene.
Fatima Khan's defence lawyer, Kerim Fuad, said his client was ashamed about the video but she had been left to "carry the can" by Raza Khan, who had attacked Mr Safi out of "macho madness".
Describing her as "Ilford's Snapchat queen", he said Khan used the app numerous times each day and that the video was posted among videos of her morning coffee, a cab ride and even the carpet of her family home.
Khan cried as she gave evidence, saying she suffered post-traumatic stress disorder from a past relationship.
On Raza Khan, she told the jury: "I hate him. He is so disgusting because he done something so bad. Khalid did not deserve to be dead. He disgusts me. I feel sick just thinking about it."
She will be sentenced on 30 July.