Hitbox

Hitboxes, referred to as collision boxes in FrayTools, are the main structure for how interactions are executed in the  series and Fraymakers. They primarily represent areas in which an attack is active, and when an attack's hitbox collides with an object's damageable area (also known as a hurtbox), the attack hits the object. They are present on all interactive elements of the game, such as characters, items, and stage hazards.

Elements such as characters and attacks often have multiple hitboxes, each of which has a unique index number. Should multiple hitboxes of a single hit connect with an opponent, only the hitbox with the lowest index number will be used. This order of precedence is known as a hitbox stack.

Hitboxes are rectangular in shape and are normally hidden from the player. In Super Smash Flash 2, a function exists to make most character hitboxes visible during gameplay, though this is intended only for developers and otherwise only accessible in a debug menu through hacking. Fraymakers is planned to allow hitboxes to be visible during Training.

Types of hitboxes in Super Smash Flash 2
There are twenty types of hitboxes used across Super Smash Flash 2, seven of which become visible when activated with developer controls. Additionally, several hitboxes exist within the game's code but are not used in-game.

Viewable hitboxes
This is a list of the seven hitboxes that can be viewed using developer controls, accompanied by their colors when visible and their functionalities.

Other hitboxes
This is a list of the thirteen hitboxes that cannot be viewed using developer controls, accompanied by their functionalities.

Types of collision boxes in Fraymakers
There are eleven types of collision boxes used in Fraymakers or otherwise accessible with custom content through FrayTools. This is a list of the available collision boxes, accompanied by their default colors in FrayTools and their functionalities.

Disjointed hitbox
Disjointed hitboxes are attack hitboxes that are separated from the normal hurtboxes of the character using the attack. These types of hitboxes can hit more safely at a distance without risking the player getting hit. These hitboxes tend to be found on weapons, such as swords.

Interpolation
Interpolation is the action of giving some parts of an attack hitboxes where they would not normally have them. It is often used in areas where hitboxes appeared at an earlier point of the attack, such as in the trails of a sword slash or behind a fast-moving projectile. This is used to ensure that collisions are detected properly in situations where they may otherwise "pass through" an opposing character. This process is generally not applied to characters' hurtboxes.