OpenSign vs Signicat Electronic Signature API

OpenSign is an open-source PDF e-signature solution for signing, storing, and securing documents. Users can create reusable templates with pre-placed widgets and send them through the API to one or many signers. API workflows include self-signing, drafts, signer roles, public template links, and real-time webhook notifications. Templates can be embedded in React, Next.js, HTML, JavaScript, and Angular projects. The documentation lists TLS-encrypted transport, audit trails, IP logging, and tamper-evident signed PDFs; account protection includes two-factor authentication and passkey sign-in. The free plan costs nothing and lists unlimited digital signatures and templates, completion certificates, sequential signing, OpenSign Drive, and email notifications. Its free-plan guide limits invitation emails to 15 per month; bulk sending and public links require a paid plan. Live API tokens require Professional or Teams, though sandbox tokens are available on all plans. OpenSign provides Docker self-hosting instructions for Linux, macOS, and Windows. Some SMTP features are limited to paid plans.

Signicat Electronic Signature API has no write-up on Specifiction yet; its figures are above.