After 8 years of development, we are excited to release NetHSM, the first fully open source Hardware Security Module (HSM). The professional 19" device securely stores and manages cryptographic keys and can be used e.g. for TLS keys of web servers, for DNSSEC, PKI, CA and blockchains. NetHSM is easy to integrate and operate using a modern REST interface and modern software tools (e.g. PKCS#11, CLI).