API Overview
Addo Sign provides two APIs depending on your integration setup:
New Addo Sign API (Recommended for all new integrations)
Legacy REST API (Supported for existing integrations only)
For new projects and long-term implementations, we strongly recommend using the New Addo Sign API.
New Addo Sign API (Recommended)
Access the New API documentation here: Addo Sign API V1
The New Addo Sign API delivers improved performance, modern authentication, and long-term compatibility with future platform features. It is fully supported, actively developed, requires paid access, and is the recommended choice for new integrations.
Secure token-based authentication
REST-based endpoints with modern schemas
Simplified API structure and updated request/response formats
Optimized for long-term stability and future platform compatibility
Tutorial
For a first signing tutorial please visit the following page:
⚠️ Please note that using this API for template-based requests requires all templates to have Advanced Signing enabled.
Legacy REST API
Access the Legacy REST API documentation here: Web Service API documentation
The Legacy Addo Sign REST API remains available for customers with existing integrations. It is maintained for compatibility with older implementations, requires paid access, and is not recommended for new development.
Session-based authentication using user credentials
REST-based endpoints with legacy schemas
Maintained for backward compatibility
Intended for existing production integrations only
Tutorial
For a short guide, please see the following document:
⚠️ Please note that support for the Legacy REST API is limited to maintaining existing integrations. New feature development is not supported.
From Development to Production
After completing development and testing in the demo or sandbox environment, your integration can be moved to production.
Demo Environment
You can create a demo account by clicking Create account using the following link:
Login | Addo Sign Demo
⚠️ Please note that testing services such as MitID, e-Boks, and similar third-party integrations may be limited, as these providers require separate demo or test environments.
Production Checklist
Before going live, ensure the following:
A dedicated integration user has been created for production access
Production API endpoints are configured instead of demo endpoints
Authentication tokens or credentials have been generated for the production environment
Callback and webhook URLs have been updated and tested
Signing templates and permissions have been verified in the production environment
Developer Support
Addo Sign provides standard technical support through official support channels during normal business hours, in accordance with the Addo Sign General Terms and Conditions.
If you require additional assistance such as integration guidance, setup support, or troubleshooting beyond standard support, a dedicated developer resource can be allocated. This service is provided separately, is subject to availability, and requires a paid agreement.
Reach out to our Support team ([email protected]) for technical guidance or our Sales team for pricing and access information.
Error Handling
Addo Sign provides free assistance with identifying and understanding API errors. If a non-success HTTP status code is returned, review the response body for error details and trace identifiers. When contacting Support, include the trace ID to help speed up troubleshooting.
Support can help explain error messages, identify configuration issues, and suggest possible solutions. However, implementation support such as writing custom code, debugging application logic, or building integrations is not included in standard support and may require a separate developer support agreement.