Fill the water bath canner with water on a separate stove burner to prepare the jam for the water bath.
Wash the canning jars. Place the canning jars, lids and bands in the oven at 200 degrees F to sterilize while you are making the jam (it helps to have them all in an 13x9 dish to keep them all together).
Place the peeled, chopped mangos and the peppers, seeds removed, and place in your blender. Pulse until the mangos and peppers are well chopped/broken down.
Add the mangos, peppers,, sugar, pectin, and lemon juice to your deep stock pot. Give it a stir to combine.
Crank the heat to high and bring the mixture to a rolling boil. Stir frequently, until the mixture reaches 220 degrees F. Once the mixture reaches 220 degrees F, continue to boil for 4-5 minutes.
Carefully remove the pot from the stove.
Remove from heat and ladle into sterilized canning jars, leaving 1/2 inch headspace. Wipe rims thoroughly and then apply lids and bands (finger tight).
Placed filled jars in a hot water bath, ensuring that they are covered by 2 inches of water. Place lid on water bath canner, and bring water to a steady boil.
Process the jars for 10 minutes (half pint), adjusting for altitude. Boil 10 minutes at altitudes of 1,000 feet or less. Boil one additional minute for every 1,000 feet elevation.
Turn off the heat, remove the lid and allow the jars to rest for 5 minutes. Then remove the jars entirely and allow to cool.
Check lids for seal after 24 hours. Lids should not flex up and down when center is pressed. Store jars in a cool place for up to 1 year.