The glossary to understand and take action

SECUline

SECUline is an electronic social-data exchange system used in dealings with the CCSS in accordance with the available procedures.

Démarche et formalité · Luxembourg Fiduciaries Editorial Team · Reviewed on

Understand the scope

What is this process for?

Authorisation must correspond to the mandate and authorised persons. Transmission does not replace checks of payroll data and processing acknowledgements.

In your file

How to prepare the process

SECUline enables electronic exchanges of data with the CCSS in accordance with the prescribed procedures and authorisations. The existence of payroll software is not enough to prove that transmissions have been completed. Responses, anomalies and corrections must be monitored. Where an agent is involved, specify who prepares, checks, transmits and archives the declarations in order to avoid duplicates and omissions.

A scenario to help you understand

Educational example

A firm transmits a client's social security data. The employer maintains a validation process and checks the handling of rejection messages.

Fictitious situation, presented to illustrate the concept.

Prepare for what comes next

Points to check

  • Contrôler les habilitations
  • Suivre les accusés et anomalies
  • Archiver les corrections effectuées

The practical question

Find out more

Pourquoi lire les retours de transmission SECUline ?

L’envoi ne garantit pas que chaque donnée a été acceptée et traitée comme prévu. Les retours peuvent signaler des informations manquantes ou incohérentes. Désignez la personne qui les contrôle et suit les corrections. Conservez une preuve du traitement final pour ne pas considérer une déclaration comme terminée sur la seule base d’un fichier transmis.

Connecting concepts

Terms to know as well

Continue with the concepts, contacts and procedures related to this topic.

Joint Social Security Centre (CCSS)The Joint Social Security Centre (CCSS) notably manages registrations and the collection of social security contributions within its remit.Engagement letterThe engagement letter formalises the services agreed between a professional and their client, together with the conditions for their performance.Operational declaration with the CCSSA procedure enabling a company to register as an employer with the CCSS.Social minimum wageThe social minimum wage is a statutory remuneration benchmark whose applicable amount varies, in particular, according to age, qualification and period.Wage indexationIndexation adjusts remuneration according to the legal mechanism of the sliding scale and the corresponding effective dates.National identification number — 13-digit identification numberThe national identification number of a natural person in Luxembourg comprises 13 digits and enables identification in the relevant procedures.

Put it into practice

Explore further with our guides

Practical guideSocial minimum wage and indexation: check payroll parametersPractical guidePayroll variables: building a calendar and controlsPractical guideMyGuichet.lu: organising access, mandates and continuity

Sources and verification

References consulted on 20 September 2026. Official procedures specify the applicable conditions and exceptions.

This guide explains a general process. The applicable rules depend on your situation; it does not constitute personalised advice. Report a correction.

A definition gives you a reference point. To examine your situation, clarify your question with a professional.