ESP32 Compatible NFC Sensors

Match the reader to the tag frequency, because the two common RFID worlds do not interoperate. The PN532 and RC522 work at 13.56 MHz - MIFARE cards, key fobs and NFC. The PN532 is the more capable part: it reads and writes, talks I2C, SPI or UART, and can exchange data with phones; the RC522 is the budget SPI card reader that covers plain access-control jobs.

The RDM6300 lives in the other world: 125 kHz EM4100 tags, read-only, over UART. Those are the thin fobs common in older access systems. If you are buying tags and a reader together, pick the frequency first and the reader follows.