Electronic invoicing through El Fatoora is a legal obligation in Tunisia, not a efficiency project. For VAT-liable businesses the question is no longer whether to adopt it, but how to connect the systems already running the business to it.
The part most vendors get wrong
The usual proposal is to replace your invoicing system. That is the most expensive possible answer to a format-and-transport problem, and it puts a migration between you and compliance.
Almost every business already has something that produces invoices — an ERP, an accounting package, a custom internal tool, sometimes a spreadsheet feeding a printer. The compliance requirement is that invoices leave that system as TEIF XML, carry a valid electronic signature, and reach TTN. None of that requires throwing away what produces the invoice in the first place.
What an integration actually involves
Mapping your data to TEIF. Your invoice records already contain the parties, line items, tax rates and totals. The work is mapping those fields onto the TEIF structure correctly, including the cases that break naive mappings: credit notes, multi-rate VAT, exonerations, foreign-currency lines.
Signing. Invoices must be signed with a certificate from ANCE / TunTrust. That means a signing step your system can call reliably, with the certificate handled properly rather than pasted into a config file.
Transmission and acknowledgement. Sending to TTN is only half of it. The platform answers, and those answers have to be read, stored, and surfaced to whoever needs to act on a rejection.
Archiving. Signed invoices and their acknowledgements have to be retained and retrievable for the legal period — which is a storage and search problem, not a formatting one.
How we work on this
We start by reading what you already have: where invoices are produced, what the data looks like, and what it would take to emit compliant XML from it. That assessment is the deliverable — a clear statement of what needs to change, before anyone commits to a build.
If an integration makes sense, it is delivered on a fixed scope with milestone delivery, so the price is agreed before work starts.
If your existing system genuinely cannot be adapted, we will tell you that too. We also build invoicing platforms from scratch, so we have no incentive to force an integration that will not hold.