Keycards are the major elements of the game, being the only items that can open doors by inserting the card at the slot. Keycards can be found in various places or get refined through SCP-914 to create other keycards. There are six keycard levels, 1 through 5 plus Omni. Level 0 is not in the game but it exists in the fan made mod SCP Containment Breach Ultimate Edition
Level 1
The Level 1 keycard can be found in Storeroom (in the Light Containment Zone) or in the Office Room (in the Entrance Zone). The card can be used to open the door to the Test Room (in the Light Containment Zone).
Safe access keycard.
Level 2
Level 2 keycards can be used to open the doors to SCP-914's containment chamber. It's found in the basic office or at the small testing room. It can also be obtained by placing a level 1 keycard into SCP-914 on "Fine" or a MasterCard/Playing Card on "Very Fine".
It's a safe access keycard.
Level 3
The level 3 keycard can be used to open the main door and the door to the staircase in SCP-106's chamber, SCP-895's chamber, SCP-079's chamber, SCP-012's chamber, the first door leading to SCP-714's and SCP-1025's chambers, The level 3 keycard can be obtained by placing a level 2 keycard in SCP-914 on "Fine". It is found in SCP-895's chamber or in the elevator maintenance room.
This accesses all Euclid level SCPs.
Level 4
The level 4 keycard is found in SCP-049's containment chamber, right next to SCP-049's document. It is required to access the head office. As of v0.8, this keycard can no longer be obtained with SCP-914; making obtaining a Level 5 Keycard more difficult.
This accesses all Keter and Euclid level SCPs.
Level 5
The level 5 keycard is required to open the door to the elevator leading to the warhead room, the door leading to the small control room in the warhead room, and the door in the checkpoint room between the Heavy Containment Zone and Entrance Zone. It can be found in the head office, next to the control panels which captures 106 or obtained by placing a level 4 keycard in SCP-914 on "Fine".
Can access all doors.
Key Card Omni
Key Card Omni (the one with all access) The Omni keycard currently has no unique use, but can access anything requiring a keycard. The Omni keycard can only be obtained via placing a level 5 keycard through SCP-914 on "Fine" or by placing any level keycard on "Very Fine" if it doesn't create a Mastercard