Flexible Invoices for WooCommerce – KSeF Add-on

Description

KSeF – invoice registration from Flexible Invoices is a WordPress plugin that lets you send invoices directly to KSeF (Polish National e-Invoice System). It works as an extension for Flexible Invoices and uses the official KSeF API provided by the Polish Ministry of Finance.

The plugin allows you to submit invoices from WordPress and WooCommerce straight to KSeF, without exports or external systems. invoice status, KSeF reference numbers, and error messages are all available inside the WordPress dashboard.

This plugin is an add-on for Flexible Invoices and therefore requires the Flexible Invoices plugin in min. version min. 6.2.0.
If you also want to use automatic invoice generation, or issue invoices in the OSS standard, opt for the Flexible Invoices PRO in version 5.3.0 or higher.

Key Features

  • Direct invoice registration to KSeF from Flexible Invoices
  • One-click sending of individual invoices to KSeF
  • Bulk invoice registration to the National e-Invoice System (KSeF)
  • Clear KSeF status displayed in the invoice list
  • Dedicated KSeF metabox showing:
    • invoice registration status
    • registration date
    • KSeF reference ID
    • KSeF API error messages
  • Integration with the official KSeF API
  • Full compatibility with Flexible Invoices and Flexible Invoices PRO

How it works

  1. Install and activate Flexible Invoices
  2. After installing the plugin, go to Invoices Reports KSeF to connect the store with the invoice system.
  3. Enter your KSeF API credentials in the plugin settings.
  4. Send invoices to KSeF:
    • individually with one click
    • in bulk using bulk actions
  5. Monitor invoice status and KSeF details directly in WordPress.

Data Use Policy

This plugin connects to the official KSeF API (provided by the Polish Ministry of Finance) to send invoices generated by the Flexible Invoices plugin.

This connection is required to send and verify electronic invoices (FA(2)).

When sending a document, the following data is transmitted:
– Invoice data (required by law)
– Your KSeF access token or credentials (configured in plugin settings)

This service is provided by the Ministry of Finance of the Republic of Poland:
1. API documentation
2. Privacy policy

WP Desk plugins collect anonymous diagnostic and configuration data to enhance product quality, stability, and alignment with user needs. This data is securely transmitted once after plugin activation and once a week later on, to WP Desk’s servers at testsdata.wpdesk.org and data.wpdesk.org for statistical analysis, technical issue identification, and plugin performance optimization.
All data collection is conducted anonymously, without storing personal, financial, or sensitive business information. The application does not collect data without users knowledge. Data collection requires an users opt-in through the plugin settings.

Learn more about it in docs

Screenshots

  • Invoice list with KSeF status column.
  • KSeF metabox in invoice edit screen showing status and details.

Blocks

This plugin provides 1 block.

  • KSeF QR Code KSeF QR Code.

FAQ

What does this plugin do?

It allows you to send invoices from Flexible Invoices directly to KSeF.

Does it support the FA(2) format?

Yes. All submitted invoices comply with KSeF requirements and the FA(2) format.

Can I send multiple invoices to KSeF at once?

Yes. Bulk invoice registration to KSeF is supported.

Does this plugin work without Flexible Invoices?

No. This plugin is an extension and requires Flexible Invoices to be installed and active.

Reviews

February 4, 2026 4 replies
Wpisuję token i wtyczka nie łączy się z systemem. Support dostępny tylko dla osoby posiadających wersję PRO.
Read all 1 review

Contributors & Developers

“Flexible Invoices for WooCommerce – KSeF Add-on” is open source software. The following people have contributed to this plugin.

Contributors

“Flexible Invoices for WooCommerce – KSeF Add-on” has been translated into 1 locale. Thank you to the translators for their contributions.

Translate “Flexible Invoices for WooCommerce – KSeF Add-on” into your language.

Interested in development?

Browse the code, check out the SVN repository, or subscribe to the development log by RSS.

Changelog

2.0.10 – 2026-02-09

  • Minor changes and UI updates
  • WooCommerce is no more required for this plugin to work
  • Plugin uses order number instead of order id

2.0.9 – 2026-02-04

  • Minor changes and UI updates
  • Fixed problem with sending invoices without VAT number

2.0.8 – 2026-02-04

  • Minor changes and UI updates
  • Updated API routes
  • Added support for FA (3) file

2.0.7 – 2026-02-02

  • KSeF submenu is now always visible if the plugin is active

2.0.6 – 2026-01-29

  • Added ability to send documents with customers without vat number

2.0.5 – 2026-01-26

  • Added ability to fill exempt reason
  • Duplicate handling added

2.0.4 – 2026-01-20

  • Updated API environments paths
  • Added download button for downloading XML (after enabling it with filter)

2.0.3 – 2026-01-15

  • Fixed deprecated notice on PHP version 8.4 and newer
  • Fixed fatal error related to closing session

2.0.2 – 2025-12-29

  • Removed metabox for proformas
  • Removed ability to try sending without authenticated connection
  • Changed position of settings page

2.0.1 – 2025-12-16

  • Missing repository images, updated readme

2.0.0 – 2025-12-16

  • Support for KSeF API v2

1.0.0 – 2025-07-21

  • Initial release with manual and bulk invoice sending to KSeF.