Skip to main content

MIT License

OpenKSeF is released under the MIT license.

Full license text​

MIT License

Copyright (c) 2026 OpenKSeF

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

Data and security disclaimer​

OpenKSeF is software provided "as is" (AS IS), without any warranty.

In particular:

  • The authors do not guarantee the security of data stored in your OpenKSeF instance
  • The authors bear no responsibility for data loss, security breaches, or system malfunctions
  • The user is fully responsible for configuring, securing, and maintaining their instance
  • The authors have no access to data stored on self-hosted instances

OpenKSeF operates on tax data (invoices from KSeF). Before production deployment, we recommend:

  1. Security configuration review by a qualified person
  2. Implementing HTTPS, backups, and monitoring
  3. Compliance with data protection regulations (GDPR)
  4. Regular updates to the latest versions
warning

OpenKSeF is in beta. Use in a production environment with real tax data is at the user's own risk and responsibility. There may be changes in the API and data structure between versions.