e-Filing guidance

The Ilmoitin.fi website and the interface ApitamoPKI 

Users can submit a number of tax returns, reports and notices electronically, including income tax returns, self-assessed tax returns, and annual information returns.   

The Tax Administration’s specifications of data records and format requirements should be adhered to.  The system performs a number of automated checks for ensuring compliance with these requirements. The check processes are run at the time when the user submits the files. 

Users can submit their tax returns and notices to the Tax Administration through the Ilmoitin.fi website, the delivery service for electronically provided files. Secure sign-in and authorisations with Suomi.fi are in use. For more information including lists of available return formats, the roles of filers, required authorisations for submittals, see the Ilmoitin.fi website. The services of Ilmoitin.fi are also available with ApitamoPKI, which handles massive batches of data.  

It is a responsibility of software developers to make sure that the services they produce are compatible with the Tax Administration’s requirements, such as our Data format specifications and time schedules. 

The guidance below is available for downloading (in pdf files). The guides address issues like format, check processes, and requirements for electronic submittal of files via www.ilmoitin.fi. Users are expected to take action independently and run the necessary checks to ensure full compatibility of their electronically provided tax return, report or notice. The Ilmoitin.fi website contains the checkup modules for this purpose.

Electronic filing of information returns General description (pdf) (4 Jun 2024)

The control character for verifying the authenticity of Finnish Business IDS and Personal identity codes (pdf) (12 January 2023)

Detailed instructions for error correction and examples

Corrections to self-assessment, corrections to VAT Recap Statements (pdf)

Making corrections to electronically filed annual information returns

Vero API 

The Tax Administration’s interface service aimed for resolving user situations in real time is called Vero API. The interface connects with the tax-assessment system in real time, providing responses to user’s requests and allowing the updated, real-time information to be processed. The information interchange is based on JSON messages where the usual JSON data types are in use.  

The Vero API interfaces and instructions for each service are uploaded in the dedicated interface page  Vero API - vero.fi 

In general, software developers are expected to build check routines for data entry and logic checks in accordance with the interface descriptions. The objective is to receive high-quality data from all users. This way, the number of format errors and related delays is kept down to a minimum. For description of the APIs, visit the Vero API portal. 

Maintenance breaks and information on exceptional disruptions

For updates and details about planned downtimes for maintenance, and information on exceptional disruptions, see Maintenance breaks and disruptions affecting the Tax Administration’s services - vero.fi