Open APIs

Hi TM Forum community,

We are implementing TMF678 – Customer Bill Management and are aiming to remain fully TMF-compliant, as our solution is subject to TM Forum compliance audits.

We have a question regarding extending the TMF678 data model with additional entities while still remaining compliant.

Specifically:

1. Related Party additional details

   • The standard TMF678 relatedParty structure does not expose all billing-relevant customer attributes we require (e.g. billing address, VAT number, billing email).

   • We would like to introduce an additional entity (e.g. relatedPartyCharacteristic) with a 1-to-1 relationship to relatedParty to hold these attributes.

2. Bill line items

   • Our bills contain multiple billing line items.

   • We would like to introduce a billItem entity with a 1-to-many relationship to bill, representing individual billed charges.

In both cases:

• The extensions would be linked to existing TMF678 entities, not replacing or altering the standard attributes.

• The extended structures would be included in:

  • POST /customerBill

  • GET /customerBill/{id} responses

Our intention is to extend the model, not modify or break the standard TMF678 schema, and to continue supporting the standard payload as defined by the Open API specification.

Question:
Is this approach considered TMF-compliant, provided the standard TMF678 structures and semantics remain intact and the extensions are additive?

Any guidance or references to TMF extension best practices would be appreciated.