For businesses selling online or to dealers, the sneakiest waste of time is invoicing: check the order panel, copy the details, enter them in the portal, issue the invoice, email the PDF by hand. Thirty orders a day means an hour a day. e-Invoice integration removes that chain.
First, the terms: e-Invoice or e-Archive?
- e-Invoice (e-Fatura): issued when the buyer is also registered in the e-invoice system; the document reaches them through the tax authority's system.
- e-Archive invoice (e-Arşiv): issued when the buyer isn't registered — most end consumers; it is sent to the customer by email or link.
In practice this is the integration's first job: checking the buyer's tax/ID number and deciding by itself which document to issue. Done by hand, the wrong document type is the most common error.
Note: who is obliged, plus thresholds and deadlines, change with legislation — confirm the current rules with your accountant or the tax authority's announcements.
How does e-invoice integration work?
The chain has three links: your sales channel → ERP/accounting → integrator (tax authority).
- Payment for an order is confirmed on your site or panel.
- The system turns the order data (buyer, line items, VAT rates, discounts, shipping fee) into an invoice format.
- It is sent to the integrator over an API; the document number and status come back.
- The invoice is delivered to the customer automatically, and the PDF/UUID is written onto the order record.
- Accounting sees the same record — nothing is entered twice for reconciliation.
We covered the wider ERP connection in Connecting Your Website to Your Accounting/ERP Software, and Mikro-specific scenarios in Mikro integration.
What do you need?
- A financial seal / e-signature (an e-signature for sole traders),
- An agreement with a private integrator (or a direct/private integration method),
- Clean order data: company title, tax/ID number, tax office and address collected correctly in the form,
- An invoice template: designed to match your brand without breaking the required schema.
The most common mistakes
- Missing or wrong customer details: if the "billing details" step is optional, the invoice can't be issued. Tax number and tax office must be mandatory for corporate buyers, and the tax/ID number's digit check should run in the form.
- VAT and discounts applied wrongly: unless shipping fees, coupons and partial refunds are modelled from the start, the invoice total won't match the order total.
- Forgetting the cancellation/refund flow: cancellation rules differ between e-archive and e-invoice, and a refund usually requires a return invoice. This flow belongs in the integration from day one.
- A one-way design: if the integrator's error message (for example "buyer is an e-invoice taxpayer") isn't written back, orders with no invoice pile up silently. Keep an invoice status field on every order.
- Skipping the test environment: before going live, run every scenario (e-invoice, e-archive, refund, partial refund) in the integrator's test environment.
What do you gain?
- The 2–3 minutes of manual entry per order goes to zero,
- Corrections caused by typos and missing invoices stop,
- The customer receives their invoice automatically, without waiting,
- Month-end reconciliation matches the order list exactly.
The same logic applies to shipping integration and marketplace integration: every post-order step should advance on a trigger, not by hand.
To connect your e-invoice/e-archive flow to your site and accounting software, see our API integrations service and get in touch — tell us which integrator and which accounting software you use, and we'll build the flow together.