Selecting the correct chip is the most critical technical decision. For most retail and marketing applications, the NTAG series (e.g., NTAG213, 215, 216) is the industry standard due to its universal compatibility with all NFC-enabled smartphones. If your project requires high security or encryption (such as for payment or access control), you should specify MIFARE DESFire or NXP ICODE chips. Always verify the user memory capacity (measured in bytes) to ensure it can store your intended URL, contact info, or data payload.