Do all fruits have a pit or seed inside?

Not every fruit has a pit or seed inside. Strawberries have seeds on the outside. The strawberry is an aggregate accessory fruit because it doesn't spring from the ovary of the plant, but from the receptacle that holds the ovary.

All the seeds on the outside of the strawberry are tiny ovaries holding a seed. The scientific name for these tiny ovary/seeds is achene. There can be 200 achenes on a single strawberry.

Despite this, strawberries don't reproduce through their seeds, but through runners. Some varieties of strawberries bear only a single crop in summer, while others have a second crop in late fall.