Gently pick through the crab meat in a medium bowl to remove any shell pieces. Fluff it up lightly with a fork.
Add the cracker crumbs to the crab meat and gently stir with a fork or spatula until just combined.
In a smaller bowl, whisk together the mayonnaise, egg, parsley, lemon juice, Worcestershire sauce, mustard, melted butter, and Harissa seasoning.
Pour the wet ingredients into the crab and cracker mixture. Mix gently until everything is evenly moistened.
Use a large cookie scoop to portion the mixture into six crab cakes. Place them on a plate and refrigerate for about 10 minutes to firm up.
Place the chilled crab cakes in the air fryer basket, ensuring they don't touch. Air fry at 375°F (190°C) for about 12 minutes, flipping halfway, until golden brown and heated through.