Keiyaku Daijin, operated by TeraDox Inc., is a Japanese electronic signature and contract workflow platform focused on simplicity and affordability. It offers an entry-level free plan.

Keiyaku Daijin provides Advanced Electronic Signatures compliant with Japan’s Act on Electronic Signatures and Certification Business, including email verification, timestamps, audit logs, and agreement certificates.

The platform supports multi-party signing for up to five signatories in sequential (relay) mode, internal approval workflows, reusable templates, reminders, and the ability to attach an optional supplementary PDF per contract, which is also signed and timestamped.

It is optimized for small businesses and freelancers, with an intuitive interface, group and permission controls, folder-based storage, full-text search, and optional API or CSV integrations.