NTAG424 SDM — Developer & Hobbyist Portal
This is a test and development server built to help developers, integrators and hobby enthusiasts work with NXP NTAG 424 DNA NFC tags. Our goal is to provide a free, open and reliable tool for verifying SDM-enabled cards, understanding the cryptographic flow, and testing custom implementations — without needing to build your own backend from scratch.
| Purpose | Free verification endpoint for NTAG 424 DNA cards using Secure Dynamic Messaging |
| Who it's for | Developers building NFC-based systems, researchers, students and RFID hobbyists |
| What you can do | Verify tap authenticity, test custom keys, inspect decoded payloads and CMAC integrity |
| Cryptography | AES-128-CBC, AES-CMAC, ISO/IEC 9797-1 M2 padding, NXP key diversification |
| Data privacy | No tag data, UIDs or payloads are stored. Custom keys exist only in your signed session cookie. |
| Cost | Free to use — supported by advertising |
Beyond the free test portal, we offer professional services for teams and businesses building production NFC systems.
We can deploy a dedicated API instance on a separate physical server under your control. Your AES master keys never leave your infrastructure — the API runs on-premises or in your private cloud, processes tag data locally, and returns decoded results over an encrypted channel. Ideal for high-security deployments where key material must not be shared with third parties.
A ready-to-use hardware programmer for configuring and personalising NTAG 424 DNA cards and tags. Sets up SDM (Secure Dynamic Messaging), writes key slots, generates diversified keys per card UID and programs the NDEF URL template — all in a single tap. Suitable for both low-volume desktop use and higher-throughput batch operations.
Desktop software for deep inspection and debugging of RFID cards and NFC tags. Read raw file data, inspect file settings, decode SDM mirrors, verify cryptographic chains step by step, and simulate tap events — all without writing to the card. Invaluable during development and integration testing.
Interested in a private API deployment, hardware programmer or debug software? Have a question about the portal or a custom NFC project? We are happy to discuss your requirements.
This portal is open for testing and does not guarantee uptime or data retention. It is intentionally kept simple and transparent — the cryptographic logic follows the NXP NTAG 424 DNA application note (AN12196) and the SDM/SUN specification exactly.
If you find a bug, a discrepancy with the spec, or want to contribute improvements — reach out via email. We welcome feedback from the NFC developer community.