Build an SGInvoice from structured data and serialize it to UBL 2.1 XML.

invoice_data['profile'] (CustomizationID) and invoice_data['business_process'] (ProfileID) select PINT-SG or SG Peppol BIS Billing 3.0, and must be a matched pair (TX2_Annex Annex B) — use get_profile_urn_sg to look up both values together rather than setting them independently. Returns the UBL XML (as a string) plus the customization_id/profile_id that were applied. Does not validate against Schematron — call validate_invoice_sg on the returned XML for that.

Validate a UBL 2.1 XML invoice against IRAS's C5 acceptance-layer Schematron.

Runs IRAS's own C5 acceptance layer (checks documents that IRAS itself would still reject, e.g. a missing buyer/seller UEN). The CEN EN16931 base ruleset, PINT-SG's own jurisdiction overlay, and SG Peppol BIS Billing 3.0 are NOT checked — see scope and the EN16931-BASE-UNAVAILABLE warning in the result, and validators/schematron.py's module docstring for why (SGInvoice's GST category codes have no sourced crosswalk to the UNCL5305 code list the base ruleset requires; tracked as [CORE-EN16931-BASE-SG-CROSSWALK-1] in context-library/roadmap-2026.md).

Requires the optional xslt2 extra (pip install mcp-invoicenow-sg[xslt2]) — the bundled stylesheet needs XSLT 2.0. If missing, returns level="unavailable".

Return the IRAS GST category codes accepted on Singapore invoices.

Source: IRAS e-Tax Guide Annex E (supply/output-tax side only — the purchase-side codes are out of scope for sent invoices). rate is null for categories with no fixed rate ("NA" in the source table).

Return the CustomizationID (BT-24) and ProfileID (BT-23) for a Singapore profile.

CustomizationID comes from mcp_einvoicing_core.profile_registry (registered at import time in models/invoice.py); ProfileID is a shared Peppol process identifier, not per-country, so it is returned from a local constant rather than the registry.

PINT_SG is the recommended profile for new senders — SG Peppol BIS Billing 3.0 (BIS3) predates the PINT programme and is positioned as legacy (context-library/countries/sg.md, "Supported wire formats and profile URNs" — user-supplied guidance, not independently verified against an IRAS/IMDA notice). Not enforced as a hard default here; callers choose explicitly.

Check whether a business is registered on the Peppol network.

Performs a DNS-over-HTTPS U-NAPTR lookup followed by an SMP service-group request to determine registration status and the list of supported document type identifiers.

Fetch the AS4 endpoint for a Peppol participant's document type.

Resolves the SMP hostname via DNS, then fetches service metadata for document_type_id. If the SMP returns a redirect, the result's redirect_url is set and endpoint_url is None; callers must not follow more than one redirect hop (SMP 1.4.0 §3.2).

Resolve the SMP hostname for a Peppol participant via DNS only.

Performs the raw U-NAPTR (SML) lookup without fetching the SMP service group, useful for diagnosing whether a participant is registered in the SML independently of SMP reachability.

Send a UBL/CII invoice to a Peppol participant via AS4.

Looks up the recipient's AS4 endpoint (SMP), builds the ebMS3/AS4 envelope, and transmits it using the supplied signing credentials.

List Peppol participant identifier (ICD) schemes from the OpenPeppol eDEC code list.

Requires EINVOICING_PEPPOL_CODELIST_DIR to point at a local copy of the eDEC "Participant Identifier Schemes" GeneriCode export (not bundled with this package, no confirmed redistribution rights, see mcp_einvoicing_core.peppol.codelists module docstring).

List Peppol document type identifiers from the OpenPeppol eDEC code list.

Requires EINVOICING_PEPPOL_CODELIST_DIR (see list_participant_id_schemes).

List Peppol process identifiers from the OpenPeppol eDEC code list.

Requires EINVOICING_PEPPOL_CODELIST_DIR (see list_participant_id_schemes).

List Peppol SPIS use case identifiers from the OpenPeppol eDEC code list.

Requires EINVOICING_PEPPOL_CODELIST_DIR (see list_participant_id_schemes).

Check whether a (scheme, value) pair is a recognized Peppol document type identifier.

Requires EINVOICING_PEPPOL_CODELIST_DIR (see list_participant_id_schemes). Searches all entries regardless of state, so a historical (deprecated or removed) document type is still reported as found.

Check whether a (scheme, value) pair is a recognized Peppol process identifier.

Requires EINVOICING_PEPPOL_CODELIST_DIR (see list_participant_id_schemes).

Check whether a 4-digit ISO 6523 ICD code (e.g. "0208") is a recognized Peppol scheme.

Requires EINVOICING_PEPPOL_CODELIST_DIR (see list_participant_id_schemes).

Report the OpenPeppol eDEC code list release version(s) currently configured locally.

Search the Peppol Directory for registered participants.

Public, unauthenticated search (no relation to SMP lookup). At least one of q/participant/name/country/doctype must be supplied.