Updated on
27/11/2025
SECUline
What is SECUline? — SECUline is a secure, standardized electronic communication system that enables employers, payroll providers, and accountants to exchange mandatory social security data with the Centre commun de la sécurité sociale (CCSS) in Luxembourg. This platform facilitates fast, efficient, and completely secure transmission of employee declarations, salary information, and other required reporting to Luxembourg's social security authority.
Who must use SECUline? — SECUline is available to all employers and their authorized representatives such as payroll providers and accountants. Most businesses choose to adopt SECUline due to its efficiency advantages and the increasing digitalization of administrative processes with the CCSS.
What are the main advantages of using SECUline? — SECUline offers several key benefits that streamline social security administration:
- Single data entry generates multiple required declaration files automatically
- Reduced error rates through standardized formatting and validation
- Immediate electronic feedback from the CCSS enables rapid corrections and updates
- Simplified reconciliation between employer calculations and CCSS invoicing
- Guaranteed secure and confidential data transmission
- Faster processing times compared to paper-based submissions
What types of declarations can be submitted through SECUline? — Employers can submit various mandatory social security declarations through SECUline, including monthly salary declarations (DECSAL), employee affiliation and exit notifications (DECAFF), work incapacity notifications (DECMAL), and requests for social security numbers (DEMMAT). The system also handles related processes such as identity document transmission (CARTID), social security number assignments (MATASS), and missing salary reminders (SALMAN).
Each declaration type has specific formats and requirements, with automatic error notification files like SALRET, AFFRET, MALRET, and MATRET providing immediate feedback when records cannot be processed.
How does an employer activate SECUline? — To begin using SECUline, employers must first request a SECUline identification number from the CCSS. After receiving this number by post, they contact Worldline Financial Services (Europe) S.A. to obtain and install the SOFiE (Secured Online File Exchange) transmission tool, which includes a LuxTrust SSL certificate ensuring secure data transfer. This combination of the SECUline number, SOFiE software, and LuxTrust certificate provides optimal security for all transmissions.
What is the relationship between SECUline and MyGuichet.lu? — As of late 2025, the CCSS has launched official online services for employers and their representatives available through the professional space on MyGuichet.lu, complementing the existing SECUline system. While SECUline remains the primary channel for automated file-based declarations, MyGuichet.lu provides additional online services and an integrated digital ecosystem for interacting with Luxembourg's social security administration.
What happens if errors occur in SECUline submissions? — SECUline includes built-in quality control mechanisms. When declaration files contain errors, the CCSS automatically sends return files indicating which records could not be processed and why. These error notification files use specific naming conventions to help employers quickly identify and correct issues, ensuring compliance with social security reporting obligations and avoiding potential penalties.