News for software developers – 03/2026

New version of Ilmoitin.fi has been launched on 2 June 2026

Key changes:

• The submission of Tax at source applications enclosure files has been simplified:
  • In the Ilmoitin.fi service, it is no longer required to enter the Application type, Application ID, or Attachment type.
  • Multiple attachments can be submitted at the same time.
  • The file name no longer needs to include the attachment type, and all attachments related to the same Application ID can be combined into a single PDF file.
  • The file name only needs to begin with the Application ID, followed by a unique identifier separated by an underscore.
• FATCA / Rule change:
  • When the value of the AcctNumberType attribute is set to OECD601, Ilmoitin activates IBAN account number validation. In this case, the account number must be in IBAN format. If the attribute is not present or has any other value, validation is not performed.
• CRS/DAC2 / Rule change:
  • The nameType attribute of Name elements may only have the value OECD207.
• In the end of September production release, the Archive functionality will be changed so that submitted files can no longer be opened.

News about Vero API

The total count of service calls and how to manage the load

Vero API interfaces will limit the number of calls to be processed simultaneously. This is done in order to safeguard service stability, and to provide a fair distribution of user access.

• If there are many service calls – going beyond the capacity of the interface at a certain time – the interface will return an “HTTP 429 Too Many Requests” error message.
• It is advisable for interface users to consider load management aspects. This is an essential part of the software implementation. As a result, users will need to ensure that the count of calls can adapt to the current capacity of the interface. 

For more information on how to deal with an HTTP 429 message, see Common Error Scenarios and Solutions.

Development of the new Status API interface

The forthcoming “Status API” will facilitate tracking of the current status of various tax returns in process.  The API will return up-to-date information on the processing of a submitted tax return within the Tax Administration’s systems. The following categories of tax returns are planned for the first version:

• The VAT return
• VAT EU Recapitulative Statement
• Business tax return, filed by the self-employed
• Tax return for agriculture
• Tax return for forestry
• Corporate income tax return (6B)
• The annual information return on paid-out dividends

The release of the production version is planned for autumn 2026. The date is to be announced.

The Tax Administration’s certificate service

The terms and conditions of API use have been updated:

• Updated terms concern the Suomi.fi authorisation tokens.
• Users can log in to the e-service to close or revoke their certificate independently. The Tax Administration, in turn, may close a certificate in different situations including contract termination, suspected misuse, and other reasons.

For more information, see the News about certificate service page.

The Tax Administration’s events for software developers Events on Teams (organized in Finnish)

These “clinic” style events offer IT developers a wide variety of information updates. You can send e-mail to ohjelmistotalot(at)vero.fi if you have questions regarding the “clinics” – for subject, write: “Klinikka”.

• The next clinic on Teams is on Friday, 5 June 2026 at 09:00 o’clock.
• No clinic events on Teams will be organised during the summer months July and August.
• The first Teams clinic for developers this coming autumn is scheduled for 09:00 o’clock on Friday, 4 September 2026.

You can find the link for the Teams meeting on vero.fi (in Finnish).

How to contact us or make enquiries

ohjelmistotalot(at)vero.fi

You can use the e-mail address of the Tax Administration (for software houses) to ask questions related to the Incomes Register as well. We forward the questions to the Incomes Register Unit. However, we remind all users that our e-mail is:

• Intended for those who work with IT development at commercial software vendor companies
• Designed to give guidance and support to IT development
• Not at all for error processing
• Instead, if you detect an error or become aware of a technical problem, always use the observation form to inform the Incomes Register Unit of it.