Small chips at the edge
A tiny chip may stay stable for a while, but cracks tend to spread with temperature swings and wind. Keep an eye on it.
Cracks and breaks
A crack can't be made to disappear. The fix is a new pane or sealed unit in your existing frame. See glass replacement.
Tempered glass
Tempered safety glass, used in doors and many large panes, can't be cut or patched. Once it's damaged, it has to be replaced.
When the frame is the problem
If the frame is rotted, bent, or broken, new glass won't fix the opening. We'll tell you that up front.
After the repair
Let fresh glazing compound cure before you paint or clean hard around it. Clean new glass with a soft cloth and a mild glass cleaner.