Short answer: IDEX cards present a standard MIFARE DESFire credential, so they work with door readers that support DESFire over ISO 7816-4 APDU communication and supply enough field power. Most modern readers do. Because readers differ in firmware and configuration, compatibility is confirmed for a specific setup rather than for a model in general.
What a reader needs to support
IDEX cards communicate using ISO 7816-4 APDUs. PC/SC readers support this by default, but not every door reader supports ISO 7816-4 communication for MIFARE DESFire EV2 and EV3. The legacy DESFire communication standard uses native commands that are not ISO 7816 compliant; from DESFire EV1 onwards, DESFire has supported ISO wrapping of those native commands, but not all door readers have followed.
The reader also has to supply enough power through its field to drive the card's fingerprint sensor. See: Card models and configuration.
Verifying a reader
A reader that works in one deployment may need a firmware update or a configuration change in another, so verify it in your own environment: encode a credential on the card, enrol a fingerprint, add the card to your access control system as you would any other card, then present it with the enrolled finger – access should be granted – and without it – access should be denied. Both must behave correctly before a reader counts as compatible. See: Integrating with your access management system and What happens when there is no biometric match?.
Getting help with a reader
Contact us with the reader make and model, the firmware version if you know it, and the access control system you use. We will share what we know about that combination, and support you through verifying it – what to test, what a correct result looks like, and what to change if it does not behave as expected. The same details are useful if you have already confirmed a reader yourself: it helps the next customer with the same setup. See: Contact support: what to include.