Flexible Invoices for WooCommerce – KSeF Add-on

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