Every term used across our complete Fawtara guide and the rest of this blog is defined here, in one place, grouped by what it actually relates to — not an alphabetical wall of text.
Legal and regulatory
Fawtara — the Oman Tax Authority's electronic invoicing program. Not a separate company or product name; it's OTA's program name for the mandate itself.
OTA (Oman Tax Authority) — the government body running Fawtara, and the entity that accredits service providers and became an official Peppol Authority on 7 January 2026.
Royal Decree No. 121/2020 — Oman's Value Added Tax Law, issued 12 October 2020. Article 70 of this law sets record-retention periods (10 years generally, 15 for real estate) that apply to invoices whether or not they're electronic.
Tax Authority Decision No. 189/2026 — the specific instrument (published 9 August 2026) that creates the binding e-invoicing obligation and sets the Phase 1 (1 April 2027) and Phase 2 (1 October 2027) dates. It doesn't set its own penalties — enforcement runs through the existing VAT Law penalty framework.
The network
Peppol — an international network standard for exchanging business documents (like invoices) electronically between systems in a structured, machine-readable way. Oman adopted it rather than building a proprietary format.
Access Point (AP) — the technical connection point a business (or its provider) uses to send and receive documents over the Peppol network.
ASP (Accredited Service Provider) — a company formally approved by OTA to operate under Fawtara, typically by running a certified Access Point. See our full guide to verifying accreditation.
The corner model — how a document actually moves through the network. Oman's model has six roles: C1 (supplier) sends to C2 (supplier's Access Point), which delivers to C3 (buyer's Access Point), which delivers to C4 (buyer) — and, independently, both C2 and C3 also route a Tax Data Document through C5 (a Tax-Authority-facing Access Point) to C6 (OTA itself). Many general Peppol explainers only describe the 4-corner delivery path (C1–C4) and skip the C5/C6 tax-reporting flow that's specific to Oman's model.
SMP (Service Metadata Publisher) — the directory service that tells the network which Access Point a given business uses and what document types it can receive. Oman runs a centralized SMP for the whole country.
SML (Service Metadata Locator) — the top-level lookup layer that resolves which SMP to query for a given participant, before the SMP itself is consulted.
AS4 — the messaging protocol Access Points actually use to transmit documents to each other securely over the network — the transport layer underneath Peppol document exchange.
MLS (Message Level Status) — the receipt/acknowledgment mechanism that confirms whether a transmitted document was actually accepted by the receiving Access Point, separate from whether the document's content itself passed validation.
Peppol Testbed — the conformance-testing environment a provider must pass (eDelivery connectivity plus PINT-OM document validation) as part of becoming a certified Access Point.
The documents
UBL 2.1 (Universal Business Language) — the base XML standard defining an invoice's general structure (header, parties, line items, totals). Generic by itself — see our PINT-OM explainer for what makes a UBL document Oman-compliant specifically.
PINT (Peppol International) — a framework layering jurisdiction-specific rules on top of the base Peppol billing model, so the same underlying structure can be adapted per country without each country inventing an incompatible format.
PINT-OM — the Oman-specific PINT layer. A compliant Oman invoice carries a PINT-OM CustomizationID (e.g. urn:peppol:pint:billing-1@om-1), not just a generic UBL namespace.
CustomizationID / ProfileID — identifiers embedded in the XML itself that tell every system in the chain exactly which rule set to validate a document against — different values apply to standard invoices, self-billed invoices, and credit notes.
PDF/A-3 — the archival PDF standard used for the human-readable copy of an invoice. Unlike a plain PDF, PDF/A-3 allows the actual XML file to be embedded inside it, so both versions travel as one document.
Schematron — the rule-validation language OTA's official PINT-OM rule packs are written in; it's what an Access Point (or your own system) actually checks a document against before treating it as compliant.
EAS code (Electronic Address Scheme) — a coded identifier for how a party's electronic address is structured on the network. Worth checking carefully: even official example files have had EAS codes copy-pasted from other countries' templates without correcting them for Oman.
TDD (Tax Data Document) — the separate report every invoice requires, submitted to OTA via the C5/C6 path regardless of whether the buyer received the invoice through Peppol. Reporting to OTA isn't conditional on delivery succeeding.
B2C QR code — a scannable code embedded in the human-readable invoice for business-to-consumer transactions, where the buyer typically has no Peppol identity of their own. It carries a defined set of invoice details (seller name, VAT number, date, totals, and a seller identifier) so the invoice remains independently verifiable even without a registered buyer-side Access Point.
Sources: Oman Tax Authority; docs.peppol.eu; test-docs.peppol.eu/pint/pint-om; Royal Decree No. 121/2020; Tax Authority Decision No. 189/2026. For the full picture behind any of these terms, start with our complete Fawtara guide.
