Ships in Eve Online are organized into classes, varying from tiny frigates to gigantic capital ships. Ships fill different roles and vary in characteristics such as size, speed, hull strength and their potential firepower. Roles and characteristics aside, the concept of ships in Eve Online is different from other massively multiplayer online games in that ships represent players in-game, whereas in most massively multiplayer online games the player is represented by an avatar. While Eve Online introduces the players to the idea of an avatar, a player's avatar remains a two-dimensional portrait. Players move in-game within their ships and as such are represented by the ship type they choose. CCP is currently developing a feature that will allow players to move freely outside of their ships in space stations, represented by three-dimensional avatars. See the Planned future developments section.
Each of the four races has their own unique ship design preferences and varied strengths and weaknesses, although all races have ships that are meant for the same basic roles and are balanced for play against each other. This means that there is no "best ship" in Eve Online. According to their preferred style of play, the player might want to fly a ship with a huge cargo hold, one that is suited for mining, one that has a powerful array of weapons or a ship that moves quickly through space (among other capabilities); but the fluid, ever-changing nature of Eve Online means that no ship will be perfect at all of these tasks, nor is there any guarantee that the "best ship for a job" today will continue to be the best tomorrow.
Furthermore, unlike many online games, Eve does not feature racial bonuses, that is, players of different races do not gain advantages for flying ships designed by their own race. So, for instance, Gallentean pilots are just as capable of flying Amarrian starships as Amarrian pilots and vice versa, so long as they both train to fly the ship in question. Thus, players are encouraged to fly starships which meet their preferred style of play, and the game does not incentivize playing as one race over another in order to fly ships designed by that race.
In general, ships in Eve Online come in four size classes: Small starships include frigates (small, mobile gunboats) and destroyers (dedicated turret platforms and frigate-killers). Medium starships include cruisers (reliable multipurpose vehicles) and battlecruisers (heavier, more combat-oriented cruisers). Battleships (heavily armed and armoured dedicated combat-systems vehicles) make up the large size class. Extra large (or capital-class) starships include carriers (extremely large mobile bases and fleet command points), dreadnoughts (very large dedicated siege vehicles for attacking immobile starbases), supercarriers (larger versions of carriers focussed more on damage to capital class ships) and titans (supermassive all-purpose mobile battle stations).
Each spaceship within the Eve Online universe has a different set of characteristics and can be fitted with different combinations of modules subject to their fitting requirements. Ships have a wide variety of characteristics, including (but not limited to) power grid, CPU (ship's computer), capacitor size and recharge rate (functionally, a battery for activating high powered systems), energy shields, armor, maximum velocity and inertial modifier, agility, locking range and maximum number of lockable targets. Ship's systems also receive bonuses to performance depending on the level of various appropriate skills that have been trained by the ship's pilot. These bonuses usually correspond closely to the particular role that the ship has been designed for, and thus vary as widely as the roles of the ships.
One of the most important characteristics of a ship is the slots it has available for fitting modules. Each ship has a number of slots available, ranging from a handful to twenty or more. Slots and modules come in three variants: high, mid, and low power slots, with high power modules fitting in a corresponding high power slot and so on. Examples of high slot modules include weapons such as turrets and missile launchers, as well as cloaking devices, tractor beams, and other tools for mining and salvaging. Mid slot items include modules to improve shields or propulsion, repair hull damage, engage in electronic warfare, "tackle" other ships to slow or stop movement, and the like. Low slot items include armor enhancements and repair, increased cargo space, improved speed, agility, computers, or power supply, and similar utilitarian functions. Different-sized ships have different numbers of module slots, with the larger ships generally having more slots than the smaller ones.
A ship may also have one or more Rig slots which are designed to hold rigs, modules that require no power grid or CPU, instead requiring a ship resource called calibration. Installing a rig is a semi-permanent action, as unlike other ship modules a rig cannot be removed from the ship without being destroyed. Rigs come in three sizes, small, medium, and large which roughly correspond to the size of the ship, and are used to affect other aspects of the ship such as maximum speed or cargo capacity, or to augment the capabilities of other modules installed in the ship.
All ships in the game, as with other forms of equipment and technology in use, are also classed according to Tech level, from Tech I to Tech III. Tech I (or T1) ships are general purpose, relatively easily manufacturable models which perform a simple, straightforward function in a more-or-less obvious way. Tech II (T2) ships are based on T1 designs that have been modified or reinvented and which perform unique, specific roles using specialised technology which they are capable of fitting. T2 ships are considerably harder to manufacture and are only produced by certain corporations, and as such are priced well-above their basic T1 variants.
The Apocrypha patch introduced into Eve Online a new type of ship: the Tech III (T3) strategic cruiser. These highly advanced starships gain their unique qualities by being manufactured from material recovered from beyond wormholes, another new feature introduced by Apocrypha. Strategic cruisers are quite rare and expensive, and require unique skillsets on the part of manufacturers which allow the reverse engineering and integration of highly advanced technologies recovered from dead or dormant ancient civilizations. They differ from other ships in that the actual hull is modular. Players customize a hull to the specifications they want, and then add the modules separately as they would to any other ship. Only the strategic cruiser hulls can be modified in this way; other ships' hulls are set. Strategic Cruiser hulls are not by default equipped with low, medium and high slots but possess five subsystem slots which can be populated with subsystem modules that affect ship characteristics more dramatically than normal modules or rigs, such as altering the number of standard module slots that are available