Overview

OpenSign™ API v1.2 — the open-source DocuSign alternative, built for developers and trusted by enterprises.

The OpenSign™ API is a production-ready, RESTful interface for embedding legally binding electronic signatures and end-to-end document workflows into any application. Send documents for signature, build reusable templates, automate signing pipelines, and track every event in real time — all from a single, well-documented API, with no vendor lock-in.

Whether you are digitising a single contract flow or powering signatures across an entire enterprise, v1.2 gives you the building blocks to move fast while staying compliant with global e-signature standards (ESIGN, UETA, eIDAS).

Key Features

Documents — Create, send, update, revoke, and delete signature requests with fine-grained control over signers, ordering, and reminders.
Templates — Build reusable templates with pre-placed widgets and dispatch them to one or many signers in a single call.
Self-Sign — Generate self-signed documents instantly, without an invitation or signer flow.
Public Templates — Publish a shareable signing link for open intake forms — no pre-defined signer list required.
Draft Workflow — Persist documents and templates as drafts, iterate, and finalise them on your own schedule.
Signer Roles — Assign each recipient a role: signer, viewer (read-only), or approver (everything except a signature).
Password-Protected PDFs — Work seamlessly with encrypted source files via the file_password parameter.
Offline Signing Control — Toggle offline signing per template with allow_offline_sign.
Contacts & Folders — Manage your signer contact book and organise documents in OpenSign Drive programmatically.
Webhooks — Receive real-time event notifications at your own endpoint for every document lifecycle change.
Users & Credits — Retrieve account information and monitor available credits on demand.
Security & Compliance — TLS-encrypted transport, audit trails, IP logging, and tamper-evident signed PDFs aligned with international legal standards.

What’s New in v1.2

Cleaner Template Retrieval — GET /template/:id and GET /templatelist now return prefill data separately from signer parameters, with redundant fields removed for easier consumption.
Password-Protected PDF Support — Pass file_password on document, template, draft, and self-sign creation routes.
Offline Signing Control — Explicitly enable or disable offline signing per template.
Signer Roles — A new signer_role field on the signers object unlocks viewer and approver flows alongside the default signer behaviour.
Fully Backwards-Compatible — All v1 and v1.1 endpoints remain available on the v1.2 base URL. New parameters are optional unless otherwise documented.

Getting Started

Every request must include your API token in the x-api-token header:

x-api-token: <your-api-token>

→ How to generate your API token

Prototype risk-free in the sandbox environment before going live.

Available Environments

Environment	Base URL
Sandbox	`https://sandbox.opensignlabs.com/api/v1.2`
Production	`https://app.opensignlabs.com/api/v1.2`
EU Region	`https://eu-app.opensignlabs.com/api/v1.2`
Staging	`https://staging-app.opensignlabs.com/api/v1.2`

Target Audience

Developers & IT Teams — Embedding signatures and document automation into web, mobile, or backend systems.
Product & SaaS Companies — Adding white-labelled e-signature flows to their own platforms.
Enterprises & Operations — Standardising secure, auditable document workflows across departments.
Legal & Compliance Teams — Meeting ESIGN, UETA, and eIDAS requirements with verifiable audit trails.

Usage Scenarios

Automating contract creation, dispatch, and signing across sales and procurement pipelines.
Powering HR onboarding — offer letters, NDAs, and policy acknowledgements at scale.
Collecting structured input via public template links for intake forms, waivers, and applications.
Orchestrating multi-party approval flows using mixed signer, approver, and viewer roles.
Standardising legal, financial, and government document workflows with reusable templates.
Integrating signing events into downstream systems through real-time webhooks.