Keiyaku Daijin, operated by TeraDox Inc., is a Japanese electronic signature and contract platform focused on simplicity and affordability. It stores all completed documents with unlimited capacity at no extra cost, making it practical for businesses that build up contracts over time.

Recipients can sign contracts via email verification without creating an account, keeping the process simple for everyone involved.

Keiyaku Daijin adds email verification, timestamps, and activity logs to every signature, meeting the requirements of Japan’s Electronic Signature Act. Completion certificates are issued automatically when all parties have signed.

A free plan is available without requiring a credit card, letting teams try the service before committing.

The platform supports multi-party signing in a set order, internal approval workflows, reusable templates, and the ability to attach extra PDFs. API connections are available as an optional add-on.

The recipient-facing interface supports English, covering notification emails, confirmation screens, and completion documents seen by signing parties.