When I was younger, my nana made awesome peach jam and for our wedding she gave me many jars as part of our present. It was really the only kind of homemade jam I was exposed to as a kid that I liked.
After meeting my husband I decided to make some jam for us from scratch, but didn't (still don't) have canning supplies, so we made freezer jam. And it became my jam. In both ways.
Freezer strawberry jam is so easy and super delicious, but it's often full of sugar and pectin. Those two ingredients do not mix with paleo or whole 30. And honestly, I don't know if whole 30 allows jam, regardless of how it's made. I'm of the mind set that it is the same concept as a nut butter. Tread lightly and don't make it a staple of your diet. Although almond butter and macadamia nut butters do get eaten more than once a week around here....sooooooo. rules. :-S
Moving on, here is how I made some BOMB jam without pectin or added sugars (not even honey, it's not cool on a whole 30)
Whole 30 Compliant, Paleo
4 pounds strawberries
2 tbsp water
1.5 apples, peeling on but cored
1 cup washed white grapes, taste them before using and get super sweet ones for the natural sweetness
1/4 cup washed frozen cranberries (although I used about 1/3 cup but you'd probably find it pretty tart)
juice of one lemon
Wash, hull, quarter the strawberries -removing major bad spots. Place into large sauce pot with the water, turn on medium low heat. Grate the apple into the pot directly, stir. Using a blender or food processor, puree the grapes and cranberries until as smooth as can be. Pour into the pot, stir. Bring to boil, then let simmer, stiring often. Mash berries with potato masher as they start to burst, be sure to scrape down the sides of pot. Cook on low for about an hour or so, the longer it cooks, the thicker it will be. Once you've reached a still runny, but pretty gel-ing state, pour into the prepared (aka cleaned and dries) jars or containers. Let cool, then freeze for up to 6 months, refridgerator for up to a month.