Lost invoices
Fire-and-forget calls in the request: when KSeF returns an error or timeout, the invoice vanishes and no one knows.
// E-invoicing / KSeF
KSeF integration
that doesn't lose invoices.
From Feb 1, 2026, KSeF is mandatory in Poland for large taxpayers; from Apr 1, 2026 for all VAT payers. We wire you into the state system so it can withstand outages, rate limits, and overnight runs — not a fire-and-forget script that breaks on the first error.
Request KSeF integration → Penalties for non-compliance from Jan 1, 2027. Proven on 40,000+ documents.
// The problem
Most KSeF integrations are fire-and-forget. Ours isn't.
KSeF is an async, rate-limited state system that goes down and has its own state. Naive integration sends the invoice in an HTTP request and hopes. When it fails, nobody finds the invoice — and with mandatory e-invoicing, that's a straight path to a fine.
State system outages
KSeF has outages and rate limits. Without retry and queuing, your entire invoicing stops.
No reconciliation
Without verification that "reality matches", you don't know if every invoice actually arrived and has UPO confirmation.
// The solution
Durable integration, not a script
We treat external calls as durable, idempotent, persisted units of work — never fire-and-forget. We wrap foreign SDKs in an anti-corruption layer, so their quirks don't leak into your business logic.
Idempotent submission
Every call has a deterministic idempotency key — no duplicate invoices even on retry.
Retry with backoff
Transient errors and timeouts retry with exponential backoff, not hand-written loops.
Rate limiting
Shared token-bucket respects KSeF API limits even when running on multiple instances.
Reconciliation job
Periodic verification that every invoice has confirmation and none are stuck in "pending" state.
Status polling & UPO
We track submission status through to UPO confirmation — you have proof the state accepted it.
Audit log & alerting
Structured event on every state transition + alerts on terminal-failure and stuck states.
// Proof
Proven in production, not on a slide
For TrafinOil, 40,000+ invoices run through KSeF, 100% delivered. During forensic recovery we also retrieved 15,141 documents a previous pipeline had silently lost. We cut the overnight data loader from 20 hours to 30 minutes — retry, reconciliation and monitoring run in production.
40,000+ invoices through KSeF
40× faster data loader
100% invoices delivered
// FAQ
KSeF integration FAQs
// Contact
KSeF deadline is closing in.
Let's build it right.
Tell us what you're solving — what system you have and where you invoice. We'll respond within 24 hours with a concrete proposal, not a 90-minute pitch deck.
// MESSAGE
KSeF deadline is closing in.
Tell us what you're solving — what system you have and where you invoice. We'll respond within 24 hours with a concrete proposal, not a 90-minute pitch deck.