Nahki Wells' brace helped Bradford come back to rescue a draw as Colchester finished with 10 men.
Wells pounced to put the hosts ahead, before Jeffrey Monakana equalised with an angled shot and then set up Jabo Ibehre to fire the visitors in front.
Wells then levelled with a looping header after the break.
Colchester defender Daniel Pappoe was sent off in injury-time, four minutes after coming on the pitch for his tackle on Mark Yeates.
VIEW FROM THE DRESSING ROOM
Colchester manager Joe Dunne told BBC Essex:
"I thought it was an exciting game. Based on the week we've had, in terms of injuries and illness, I thought we were resilient and I'm exceptionally pleased we've come away with a point.
"It was a great response from us (after going behind), we've scored quickly on the counter attack again.
"We knew the second half was going to be difficult, we've dealt with crosses and a lot of corners, and once or twice looked threatening on the break.
"We had seven players 22 or under, that's how great we should feel about ourselves."