A private integrator is an intermediary authorised by the tax authority that sends and receives e-documents on your behalf. There are dozens in the market and their prices are close; the difference shows up in technical detail.
01. Leading Providers
İzibiz, EDM Bilişim, Digital Planet (Sovos), Uyumsoft and Foriba are the names most often encountered on the corporate side. ERP vendors such as Mikro and Logo also offer their own integrator services; buying from the same roof simplifies the integration work.
02. First Criterion: The ERP Connector
Does it have a ready, referenceable connector for the ERP you use? If so the project drops to a few days. If not, development happens over the API and cost rises tenfold. This single question settles half the decision.
03. API Quality
REST or SOAP, is the documentation current, is a test environment provided, are error messages intelligible? If you will issue invoices from your own software, these items become your daily life.
04. Pricing Logic
Credit packs, flat monthly, and how is overage charged? Check whether credits expire. In firms with seasonal trade, credits burned at year-end can amount to a serious sum.
05. Support and SLA
What matters is the phone being answered during month-end peaks. Is there out-of-hours support, is there a per-incident response commitment in the contract? Don't decide without asking a reference customer.
06. Ease of Exit
Changing integrators is common. Is bulk export of past documents free, and in what format? Asking this when signing costs far less than asking it while leaving.