KSeF Integration · E-Invoicing Software in Poland
Simplify E-Invoicing in Poland with Bytize
Bytize connects your ERP to KSeF, Poland’s National e-Invoicing System, so every invoice is sent in the FA(3) structure, assigned a KSeF number and made available to your buyer.
KSeF has been mandatory for most VAT taxpayers since 1 April 2026. The smallest sellers join on 1 January 2027.
What is E-Invoicing in Poland?
E-Invoicing in Poland runs through KSeF (Krajowy System e-Faktur), the Ministry of Finance's central platform. VAT taxpayers issue structured invoices into KSeF, which assigns each one a KSeF number, and buyers download their invoices from the same system.
An invoice that should go through KSeF but doesn't isn't a valid B2B invoice. An invoice counts as issued on the date it's sent to KSeF.
What an e-invoice in Poland must follow
- Format: XML in the FA(3) logical structure set by the Ministry of Finance
- Submission: Sent to KSeF by API or the Ministry's free tools; KSeF assigns a unique KSeF number
- Receiving: Buyers receive invoices through KSeF, not by email
- Outages: Offline modes let you issue invoices when KSeF or your system is unavailable and send them to KSeF afterwards
Who must comply
- VAT taxpayers established in Poland, and foreign businesses with a fixed establishment involved in the sale
- B2B and B2G invoices; invoices to consumers can be issued outside KSeF
- Receiving through KSeF has applied to all businesses since 1 February 2026
- Sellers with invoiced sales of up to PLN 10,000 a month have until 1 January 2027
E-Invoicing in Poland: timeline and deadlines
Poland phased KSeF in by size, with a separate date for the smallest sellers.
1 Feb 2026
2024 sales above PLN 200 million (including VAT); receiving for all
Issue in KSeF
1 Apr 2026
All other VAT taxpayers
Issue in KSeF
1 Jan 2027
Invoiced sales up to PLN 10,000 a month; invoices from cash registers
Issue in KSeF
1 Jan 2027 (draft: 1 Jan 2028)
All in scope
Penalties start
A draft law announced on 16 September 2026 would defer KSeF penalties to 1 January 2028. It isn't law yet.
How E-Invoicing in Poland works with Bytize
Poland uses a central platform: every invoice passes through KSeF, which assigns it a number before the buyer can download it.
Send invoice data
Your ERP sends invoice data to Bytize.
Build and check
Bytize builds the FA(3) XML and checks it against the Ministry's schema.
Send to KSeF
Bytize authenticates with KSeF and submits the invoice.
KSeF assigns a number
KSeF validates the invoice, assigns its KSeF number and issues an official receipt (UPO).
Buyer downloads
Your buyer retrieves the invoice from KSeF.
Handle outages
During KSeF downtime, invoices are issued in offline mode and sent to KSeF within the legal deadline.
KSeF e-invoicing solutions in Poland, built for your business
Bytize covers every KSeF requirement, from FA(3) invoices to purchase invoices and offline mode, through one integration.
FA(3) generation
Your ERP data mapped to the current FA(3) structure, including correction invoices.
Validation before sending
Schema and business checks run before submission, so KSeF rejections are rare.
Single and batch sending
Send invoices to KSeF one by one or in bulk, without manual uploads.
KSeF number and UPO
Every invoice’s KSeF number and official receipt (UPO) is returned to your ERP.
Purchase invoice download
Supplier invoices are downloaded from KSeF and delivered to your ERP as structured data.
Offline mode and QR codes
Keep invoicing during outages; invoices carry the required QR codes and are sent to KSeF automatically within the deadline.
Authentication and permissions
Manage KSeF certificates, tokens and user permissions in one place.
Several companies, one platform
Manage invoicing for multiple NIPs with clear separation.
Real-time status tracking
See accepted, rejected and pending invoices in one dashboard.
Test before go-live
Run every scenario in KSeF’s test environment first.
Benefits of E-Invoicing in Poland
E-invoicing is a legal requirement, but done well it also speeds up payments and removes manual work from your finance team. Here's what changes when you switch with Bytize.
Stay compliant without extra work
Every invoice goes through KSeF in FA(3), so you meet the mandate and avoid penalties once they start.
Get paid faster
Invoices are available to your buyer in KSeF as soon as they’re accepted, so approval and payment start sooner.
Fewer errors and rejections
Each invoice is validated against the official rules before it's sent, so missing fields and wrong tax codes are fixed before your buyer sees them.
No more manual data entry
Supplier invoices arrive as structured data your ERP can post directly, freeing your team from retyping and checking PDFs.
Audit-ready records
KSeF stores every invoice for 10 years, and Bytize keeps each KSeF number and UPO linked to your ERP records.
Ready for regional growth
Bytize also covers ZATCA in Saudi Arabia, JoFotara in Jordan and Peppol e-invoicing in Belgium and Germany.
E-invoicing software in Poland that connects to your ERP
Bytize sits between your ERP and the tax network, so your team keeps raising invoices the way it does today.
SAP
ERP
Microsoft Dynamics
ERP
Salesforce
CRM and billing
Any system
Through the Bytize API (JSON)
Custom ERP
Penalties for non-compliance with E-Invoicing in Poland
Penalties under Article 106ni of the VAT Act are tied to the invoice value.
| Violation | Penalty |
|---|---|
| Not issuing an invoice in KSeF when required | Up to 100% of the VAT on the invoice |
| Same, for an invoice without VAT | Up to 18.7% of the invoice total |
| Late sending of offline invoices or breaches during a KSeF failure | Same penalty scale |
Penalties are scheduled from 1 January 2027. A draft law announced on 16 September 2026 would defer them to 1 January 2028.
Why choose Bytize for E-Invoicing in Poland
Bytize brings clearance-platform experience from Saudi Arabia to KSeF.
KSeF integration
FA(3) invoices, batch sending, UPO receipts, purchase invoice download and offline mode, connected to SAP, Microsoft Dynamics, Salesforce or any system through the Bytize API.
Proven on live tax mandates
Bytize is a ZATCA-approved Phase 2 solution provider in Saudi Arabia and reports invoices to JoFotara in Jordan.
Works with your ERP
Connect SAP, Microsoft Dynamics or Salesforce, or any system that can send JSON through the Bytize API.
Finance-grade security
TLS 1.3 and AES-256 encryption, an append-only audit log and a tamper-evident archive. GDPR-aligned, with a SOC 2 Type I audit underway.
OpenPeppol member
Bytize is an OpenPeppol member and SMP provider, so the same platform can also send Peppol invoices to EU customers and Polish public bodies through a certified Access Point partner.
E-Invoicing in Poland: frequently asked questions
Get compliant with E-Invoicing in Poland
Tell us your ERP and invoice volume. We'll show how Bytize connects you to KSeF.