Its core product, Quell-X, generates and distributes quantum-secured keys between two points over standard telecom fibre. The core version works with third-party encryptor units, while Quell-XC pairs it with high-speed cipher units from Telsy to encrypt data across the whole link. Quell-XR is a research variant that outputs raw key data for custom post-processing and academic use. QTI also sells Ekate, a key management platform combining QKD with post-quantum cryptography, QKME for secure key storage and multi-client interoperability and QSDN, a software-defined networking layer for automating QKD links.

In June 2024, QTI's Quell-X systems and Telsy's TelsyMusaX encryptors secured live communications between the press centre in Bari and journalists at Borgo Egnazia during Italy's G7 Summit, a real-world deployment rather than a demonstration. The company has since extended its network deployments to a metropolitan data centre link in Athens, a quantum-secure link in Lisbon and a long-distance hybrid QKD and post-quantum link between Rome and Naples.

Telsy, the cybersecurity arm of the TIM Group, became a shareholder in QTI in July 2021. QTI's CTO, Davide Bacco, won an ERC Starting Grant in 2022, and the company takes part in EU-funded research programmes such as QUID, Italy's national quantum communication infrastructure rollout, and the PAISES-6G project on 6G security.