Action Replay DSi: Memory Card Required? No

No memory card needed. The Action Replay DSi:

• Plugs directly into the Game Card slot (back of DS/DSi/DSi XL).
• Game cartridge inserts into the top of the AR unit.
• Stores cheat codes in its own internal flash memory.
• No SD card, no save data storage—only cheat database.

It intercepts game code in real-time to apply cheats. Simple plug-and-play.