← User guide

ISDOC e-invoices (Czech format)

Sends customer invoices and credit notes as ISDOC 6.0.2 files, embedded in the invoice PDF as well, and turns received ISDOC files into draft vendor bills.

What it is for

ISDOC (Information System Document) is the Czech national format for electronic invoices, read by most Czech accounting software. This module adds version 6.0.2 to Odoo's electronic invoicing, next to Peppol BIS 3 and the other UBL/CII formats:

• sending — a customer invoice or credit note for a customer set to ISDOC gets an .isdoc file, and the ISDOC is also embedded in the invoice PDF (sending);
• receiving — an ISDOC file uploaded or emailed into vendor bills becomes a draft bill: plain .isdoc, an .isdocx archive, or a PDF with an embedded ISDOC (receiving).

It builds on Odoo's account_edi_ubl_cii, so it uses the standard Send dialog and the standard bill upload. It needs l10n_cz_base for Czech bank account numbers.

Four add-ons install themselves when their counterpart is present:

Legal background

ISDOC is an industry standard, not a statutory format. What the law requires is that the customer agrees to an electronic tax document: a tax document is electronic when it is issued and received electronically, and the person for whom the supply is made must agree to its use — § 26 odst. 3 of the Czech VAT Act. An ISDOC file carries the particulars of § 29, including the date of the taxable supply (den uskutečnění plnění, DUZP), which ISDOC calls TaxPointDate.

ISDOC is not one of the syntaxes of the European standard EN 16931. It does not meet the Slovak e-invoicing obligation from 1 January 2027, which requires that structure; for Slovak customers use Peppol.

Setting it up

1. Czech customers get ISDOC by default. A Czech contact with no eInvoice format of its own receives ISDOC, unless it is known to be on Peppol: Odoo's Peppol check found it, or its sending method is Peppol. Then it receives Peppol BIS 3. To choose otherwise, set the format on the contact: tab Invoicing, group Customer Invoices, eInvoice format (shown only in developer mode). A customer outside the Czech Republic gets ISDOC only when you set it there.
2. Your company and the customer need a name, street, city, ZIP, country, and an IČO (Company ID) or a DIČ (Tax ID). The export lists anything missing.
3. Bank account. The payment details are written only when the invoice has a bank account (Recipient Bank); the account is written in the domestic form (number and bank code) and as IBAN.
4. Payment symbols. With l10n_cssk_payment_symbols, the invoice's variable, constant and specific symbols are written to the file.

Sending ISDOC

Send the invoice with Odoo's Send dialog as usual. For a customer set to ISDOC, Odoo generates the file INV_2026_00042.isdoc, attaches it to the invoice and the email, and embeds it in the invoice PDF, which is converted to PDF/A-3 — the form in which a PDF and its ISDOC travel as one file. If the PDF/A conversion fails, the ISDOC is still embedded. As with every Odoo e-invoice, the file is generated once and reused for later sends.

ISDOCX archive. On a posted customer invoice or credit note, Action → Download ISDOCX downloads INV_2026_00042.isdocx: a ZIP with the ISDOC, its manifest and the invoice PDF — the third form ISDOC defines. It is kept as the invoice's attachment and replaced on every download.

What the file contains:

The invoice must be in the company currency; an invoice in a foreign currency is refused for ISDOC.

Domestic reverse charge

With account_edi_isdoc_kh (installed with the Czech control statement), a line in the Czech domestic reverse charge (§ 92a ZDPH) is exported as one: LocalReverseCharge with the commodity code (kód předmětu plnění) the control statement reports, its VAT breakdown row marked as reverse charge and kept apart from exempt supplies. See account_edi_isdoc_kh.

Receiving ISDOC

Upload the file into vendor bills, drop it on the list, or send it to the purchase journal's email alias. Accepted are a plain .isdoc file (even when the sender labels it as a generic file type), an .isdocx archive — its PDF is attached to the bill too — and a PDF with an ISDOC embedded. Files of older ISDOC versions are read as well.

The draft bill gets:

• the vendor — found first by IČO (unless the file's DIČ contradicts the partner's), then by DIČ, name, email or phone, or created when the file has a name and a DIČ; a vendor created this way keeps the IČO;
• Bill Date, taxable supply date (the supplier's DUZP), Due Date;
• Bill Reference — the supplier's invoice number — and the document's UUID;
• the variable symbol as payment reference and in the VS field, plus the constant and specific symbols, reduced to digits;
• the supplier's bank account, converted to IBAN and added to the vendor;
• the lines, with the product found by name, internal reference or barcode, the VAT taxes found by rate, and a discount worked out when the line amount differs from price × quantity. A line marked as local reverse charge (LocalReverseCharge, § 92a ZDPH) gets the chart's reverse-charge purchase tax at its rate (21% RC, 12% RC), or a tax flagged as reverse charge — never the ordinary rate, which would bill VAT the supplier never charged. If there is none, the line is left without tax and the bill's chatter says so;
• deducted advances as negative lines "Advance payment …", and the rounding to whole crowns as a line "Rounding", so the bill total matches the amount payable.

Document types 2 and 6 become vendor credit notes; all others become bills. The VAT period declared is deliberately left empty: it is when you claim the deduction, which the supplier's document cannot know. The bill is a draft; check it before posting.

Proformas from sales orders

account_edi_isdoc_sale can write a sales order as an ISDOC proforma, document type 4 (zálohová faktura, a request for an advance payment): the order number as ID, the order date as issue date, the order lines, totals, and the company's first bank account with the order number's digits as variable symbol and the order's expiry date as due date. On the order, Action → Download ISDOC Proforma downloads it and keeps it as the order's attachment.

A received proforma is read by this module like any ISDOC — as a draft bill — unless the received advances add-on is installed.

Advance invoices

With account_edi_isdoc_sale_advance, the Czech advance chain of sale_order_advance_invoice maps to ISDOC:

The advance invoice itself is a sales order and is exported as a proforma. Odoo's own down payments are reported as deposits by the base module already.

Received advance invoices

With account_edi_isdoc_purchase_advance and purchase_order_advance_invoice, imported advance documents go into the received-advance flow:

• Type 4 — proforma. A received advance is created for the supplier over the document's gross amount, with the supplier's number as vendor reference and the product Advance payment (imported), without tax. The draft bill created by the import stays, linked to the advance, with a note that it must not be posted: pay and track the advance, then delete the draft. Importing the same proforma again (same supplier and supplier's number) creates no second advance; the new draft is linked to the first.
• Types 5 and 6 — the supplier's tax document for your payment and its credit note. The bill goes to the Received Advance Tax Documents Journal, takes the taxable supply date from the file, its lines are moved to the Paid Advances Account (the long-term one for a long-term advance) and the payable to the Paid Advances Clearing Account. It is linked to the open received advance of that supplier found, in this order, by the order reference in the file, by the variable symbol, or as the only advance waiting for a tax document whose paid amount equals the document total. If none or several match, the chatter says so — link it by hand.

See the supplier's tax document for what happens next.

Limitations

• eInvoice format is visible only in developer mode. Whether a Czech customer is on Peppol is known only from the installed Peppol modules; one not checked yet gets ISDOC.
• Invoices in a foreign currency cannot be exported. On import, the amounts in the local currency are used.
• Debit notes (type 3) and simplified tax documents (type 7) are imported as ordinary bills.
• Without account_edi_isdoc_kh the export does not write ISDOC's local reverse-charge element: a reverse-charge invoice goes out as a supply without VAT, with no commodity code.
• A vendor without a DIČ that is not found by IČO, name, email or phone is not created; choose it on the bill.