Yes. Crab spiders are real spiders in the family Thomisidae. Montana State University Extension notes they are named for their crab-like appearance and movements, and that they stalk or ambush prey rather than relying on silk webs to catch insects.
Some species, including goldenrod crab spiders in the genera Misumena and Misumenoides, hunt on flowers and can change color to match their background. Others, such as Xysticus, are more often found in leaf litter, grasses, or ground cover. They are generalist predators and are considered harmless to people and pets.
Source: Crab Spider: Family Thomisidae — Montana State University Urban IPM