01What is an e-invoice?
An e-invoice is a structured electronic document that contains all the elements of a classic invoice but in a machine-readable format (XML) — not as a PDF or scan, but as data that the buyer’s system can post automatically without manual entry.
The EU has standardised the e-invoice under EN 16931 (the semantic model) and the UBL 2.1 format (Universal Business Language). The specific profile for cross-border exchange is Peppol BIS Billing 3.0 — the standard REDOK uses for every outbound invoice.
In Slovenia, alongside the EU standard the national specification e-SLOG 2.0 also applies — REDOK covers both layers in a single pass.
02Slovenian e-SLOG 2.0
In Slovenia the e-SLOG 2.0 standard is the national specification for structured electronic invoices, aligned with the European norm EN 16931. B2G invoices (to the public sector) must be exchanged as e-invoices through UJP (the Public Payments Administration); the B2B market is rapidly moving to the same standard, as large retailers and manufacturers require e-SLOG from their suppliers.
REDOK is the information intermediary for e-SLOG exchange:
- We forward the e-invoice via the UJP / Peppol network directly to the recipient.
- We receive and store status responses (EOR, ZOI, delivery confirmations).
- We validate syntactically and semantically before sending — errors caught at source.
- We archive the original document and the response for at least 10 years, integrity sealed.
The customer only sees a green check — behind the scenes REDOK handles REST calls to UJP, retry logic, edge cases (gateway down → deferred submission), audit trail and reporting.
03For sellers / For buyers
E-invoicing is a two-way exchange. REDOK covers both sides — outbound invoices (you issue to customers) and inbound (you receive from suppliers).
Outbound e-invoices
You generate the invoice in your ERP — REDOK validates it, signs it with an electronic signature, sends it via the e-SLOG network and delivers it to the buyer (via Peppol or directly).
- UBL 2.1 / Peppol BIS 3.0
- EOR and ZOI automatic
- Electronic signature (eIDAS)
- PDF attachment for human review
Inbound e-invoices
You receive invoices from suppliers — REDOK validates them against EN 16931, converts them into your ERP format, and delivers for automatic posting.
- Automatic detection of VAT number, seller and amounts
- Match against the purchase order (3-way match)
- Notification of rejected invoices
- 10-year archive with full-text search
04Technical details
Supported formats
- UBL 2.1 — primary outbound format, Peppol BIS Billing 3.0 profile
- CII (Cross Industry Invoice) — UN/CEFACT, ZUGFeRD compatible
- EDIFACT INVOIC D96A/D01B — legacy EDI routes to large retailers
- e-SLOG XML — Slovenian national profile
- PDF/A-3 with embedded XML — hybrid format for human + machine review
Validation
Before an e-invoice leaves the REDOK network, it goes through four validation layers:
- Syntactic — XML schema validation
- Semantic — EN 16931 business rules (BR-01 through BR-66)
- Profile-specific — Peppol BIS BR-PEPPOL-, or Slovenian BR-SI-
- Customer-specific — custom business rules by agreement
Signing and archive
Every outbound e-invoice is signed with a qualified electronic signature (eIDAS), with a time stamp (TSA), and stored in the e-archive that guarantees integrity through a SHA-256 hash chain. Statutory retention is 10 years; many customers keep documents longer for internal purposes.
05Pricing
Two models — pick what fits
- Super Offer — €12 / month for 16 invoices (SI/B2B). Ideal for small and medium s.p./d.o.o. that know their monthly volume.
- Prepaid — from €0.07 per invoice, no monthly subscription. Pay only what you use. Ideal for seasonal business or pilot integrations.
The price includes e-SLOG delivery, sending, receiving, archive, helpdesk and updates in line with regulation. For enterprise volumes (10,000+ invoices monthly) and custom integrations we have a separate price list — contact us for a tailored quote.
06Frequently asked questions
Do I need REDOK if my ERP already supports e-invoices?
Not strictly, but most ERPs only generate the XML — they don’t deliver it via the UJP / Peppol network, don’t sign with eIDAS, don’t archive in line with the law and don’t route via Peppol. REDOK is the layer that solves all of this in a single pass, without touching your ERP.
Do I need a certificate for e-SLOG?
No — you don’t need a separate certificate. REDOK uses its own qualified certificate for the electronic signature, so there’s nothing for you to arrange.
What if UJP doesn’t respond?
REDOK retries in line with the law (deferred submission within the prescribed window). We deliver the invoice to the buyer with a provisional status until confirmation arrives; the customer can also issue the invoice before delivery, in line with regulation.
Can I send e-invoices abroad?
Yes — via the Peppol network you send to 30+ EU/EEA countries that are on Peppol. For non-EU partners we use other routes (DBNA, partner networks). Every recipient receives the invoice in their local format.
What does onboarding look like?
A typical onboarding is 5-10 business days: (1) contract and certificate, (2) technical connection to your ERP, (3) test messages, (4) UAT with real invoices, (5) go-live. We have ready-made connectors for every major Slovenian ERP.
What if I decide to leave?
Within 30 days we export your entire archive in UBL/XML format (and optionally a PDF/A-3 bundle) free of charge. Your data is always yours.