Preheat the oven to 140°C to sterilize the jars.
Wash jars and lids in warm soapy water, rinse, and dry upside down in the oven.
Place a clean plate in the freezer to chill for later testing.
Remove seeds and membranes from peppers and chillies, then chop them very finely.
Combine chopped vegetables, sugar, vinegar, and tomatoes in a wide saucepan.
Slowly bring to a boil while stirring until the sugar dissolves.
Boil vigorously for 7 to 10 minutes until the liquid reduces by half.
Remove from heat and stir in the liquid pectin.
Return to heat and boil for two additional minutes.
Test for setting point by placing a spoonful on the chilled plate and checking for wrinkles.
Cool for five minutes before pouring into the sterilized jars.