Using a Phone as a Fiscal Device in Türkiye (2026)

These rules are specific to Türkiye, where retail businesses are normally required to use a state-certified fiscal cash register (ÖKC). The only official way to use a phone or tablet in place of that device is the Secure Mobile Payment and Electronic Document Management System (GMÖEBYS), established by General Communiqué No. 507 of the Tax Procedure Law. This is the system informally called "GMÜS"; there is no official document called a "GMÜS certificate". The process has two legs: you sign a membership agreement with a GİB-licensed operator institution, then file an electronic application on the tax authority's portal and confirm a commitment. Once approved, every sale is collected through the phone and instantly converted into an e-document, and the obligation to use a fiscal cash register is lifted. This guide reflects the legislation in force as of August 2026.

GMÜS, GMÖEBYS or GMU: untangling the names

Searching for this system online surfaces three abbreviations; they are layers of the same thing.

Abbreviation	What it is	Official?
GMÖEBYS	The system itself: Secure Mobile Payment and Electronic Document Management System	Yes; the name used in the communiqué and all GİB guides
GMU	Secure Fiscal Application: the app on your phone that turns a collection into an e-document	Yes; the name used in the technical guide
GMÜS / GMUS	The industry's informal name for the same system ("Secure Mobile Payment System")	No; it does not appear in GİB's communiqué, guides or e-document pages

The practical takeaway: when a vendor offers to "get you a GMÜS certificate", what is actually meant is GMÖEBYS membership. There is no licence, plate or certificate to obtain; there is an operator membership and a GİB application. The system has been live since 1 September 2019, and as of August 2026 the text of Communiqué No. 507 has never been amended.

Who can apply

Enrollment is voluntary, not mandatory. Article 5/1 of Communiqué No. 507 opens the system to six taxpayer groups:

1. Taxpayers whose commercial income is assessed under the simplified method
2. Taxpayers keeping books on the operating-account basis
3. Taxpayers keeping books on the balance-sheet basis
4. Self-employment income earners
5. Agricultural income earners taxed under the actual method
6. Tax-exempt tradespeople (having no document obligation, they issue a non-fiscal "information slip" instead)

Restaurants typically fall into group 2 or 3; corporate-tax-paying companies belong to the balance-sheet group. Sole proprietorships built around delivery or courier operations are also in scope. If you are opening a new venue, this decision belongs in your launch plan; for the classic route, see the restaurant fiscal cash register checklist.

The application, step by step

The official flow is defined in GİB's GMÖEBYS Application Guide of July 2021. That guide belongs to the Interactive Tax Office era; its functions now live under the Digital Tax Office (dijital.gib.gov.tr), where the application sits in the post-login menus. Because screen names can change, we present the steps as they appear in the official guide:

1. Choose an operator institution and sign a membership agreement. The official list of GİB-licensed operators is published on ebelge.gib.gov.tr (see the next section). The GİB application cannot be completed without an agreement; the application screen asks you to select the operator you signed with.
2. Log in to the Digital Tax Office with your tax credentials and open the GMÖEBYS application under the e-document and petition services. In the 2021 guide this screen is called the "Secure Mobile Payment and Electronic Document Management System Application Request" page.
3. Fill in your taxpayer details. The first step lists the licensed operator institutions; you select the one you signed with and enter your tax ID, legal name, address, e-mail and registered office details.
4. Enter the company contact's details: national ID number, name, surname, mobile phone and e-mail.
5. Review the summary screen and confirm the commitment at the bottom of the page. This confirmation completes the application.
6. Print the application document and send it to your operator institution. According to the guide, the document is retrieved from the application status section.
7. Wait for your account to be opened. The operator institution opens your e-document user account through its private integrator; once GİB approves, you start using the system.

How to choose an operator institution

You do not get the system directly from GİB but from a bank, an e-money or payment institution, or an ÖKC manufacturer that holds an "operator institution licence" from GİB. The current official list, with names and contact details, is published on GİB's e-document site: Operator Institution List. The list changes over time, so always check the live version; as of August 2026 it contains 15 institutions.

When comparing operators, look at three things:

• Pricing: ask for the total of membership fees, per-transaction commission and e-document credit costs. GİB has the authority to set maximum fees (art. 4/5), but differences between operators are real.
• POS software integration: if the POS software you use can connect to the operator's GMU as an "external sales application", order lines flow into the document automatically instead of being retyped. In a restaurant, this is the item that shapes daily life.
• Support: your entire collection flow will depend on one application, so a support line you can actually reach during an outage is essential.

One nuance: an operator selling or renting you a device does not make you dependent on that device. Ownership of the phone, tablet or mobile POS in use belongs to the taxpayer as a rule; even where the operator owns the device, it cannot block other operators' applications from running on it. Business models that force a commercial tie through device dependency are declared contrary to the spirit of the communiqué in the technical guide.

After you join: the rules you live by

The ÖKC exemption the system grants is not free; the price is documentation discipline.

• Every collection goes through the system. Cash, card, bank transfer/EFT, meal cards and gift cards are all recorded in the system and matched to a fiscal transaction. The system is required to block any collection that does not match one.
• Reverting to paper is banned; paper backup is mandatory. Once enrolled, fiscal documents may only be issued electronically except in force majeure and the cases under Communiqué No. 494 (art. 5/2); for those cases you must keep a sufficient stock of pre-printed documents (art. 6/6). Blank invoice pads in the drawer for when the internet dies are not a preference, they are a communiqué requirement.
• Abstract product names are banned. Writing generic names such as "food, beverage, groceries" on a document is prohibited; every line goes in under its concrete name (like "Adana dürüm"). The responsibility sits with the taxpayer; your POS menu must carry over to the document line by line.
• The device is yours. Ownership stays with the taxpayer as a rule and vendor lock-in is prohibited (see the previous section).
• The ÖKC exemption starts and ends with membership. While enrolled, you are not required to use a fiscal cash register (art. 5/3); if you already own one, you may keep using it for sales that can be documented with a retail receipt, so hybrid operation is possible. For the details of the exemption and its e-document counterpart, see the ÖKC exemption and e-documents guide.

Leaving the system

Neither the communiqué nor the taxpayer guide describes a separate "cancellation petition" procedure; the essence of exiting is a termination notice to your operator institution. Under the technical guide, the operator must report a taxpayer whose agreement has ended or been terminated to GİB the same day and have the account closed. Two protective rules matter: the exit procedure and its timeline cannot be longer than or different from the enrollment procedure, and a taxpayer's debt to the operator cannot be used to block an exit request.

The tax consequence of leaving is clear: a taxpayer who exits the system and falls under the ÖKC obligation must return to the new-generation fiscal cash register regime. For the general framework, see the fiscal cash register guide for Türkiye.

Common misconceptions

Many guides online describe this system with outdated amounts or the wrong names; these six errors come up most often:

1. "There is a communiqué or certificate called GMÜS." Wrong. The official name is GMÖEBYS and the application is the GMU. No official document called a "GMÜS certificate" exists; the process is operator membership plus a GİB application.
2. "The phone replaces the cash register and nothing else changes." Incomplete. The price of the exemption is documenting every sale through the system with e-documents; reverting to paper is banned outside force majeure, and keeping pre-printed backup documents is mandatory (art. 6/6).
3. "The system is only for card payments." Wrong. Every collection type, cash included, passes through the system and is matched to a fiscal transaction.
4. "We'll just write 'meal' on the document." Not allowed. Abstract and generic product names are banned; every line enters under its concrete name and the responsibility is the taxpayer's.
5. "I have to buy the operator's device." No. Device ownership stays with the taxpayer as a rule; vendor lock-in is explicitly prohibited in the technical guide.
6. "The anonymous-customer limit is 500 TL." Outdated; that was the amount in the 2021 guide. The current rule ties the limit for issuing an e-Archive Invoice marked "Nihai Tüketici" (final consumer, no customer name required) to that year's invoice-issuance threshold: 12,000 TL for 2026 (VUK Communiqué No. 588).

Frequently asked questions

How long does the application take? The legislation sets no explicit deadline. The electronic application on the GİB side takes minutes; account activation depends on the operator institution creating your user account through its private integrator and on GİB's approval. Ask your chosen operator for a timeline.

Does joining GMÖEBYS also solve e-Adisyon? No. e-Adisyon (the voluntary electronic order slip under Communiqué No. 509) is a separate application; the 507 system does not replace the order slip, it solves the sales, collection and invoicing layer.

What does the customer get instead of a receipt? The e-document issued at the time of sale (typically an e-Archive Invoice) is delivered to the customer electronically by SMS or e-mail, and/or on paper. In 2026 it can be issued without asking the customer's name, marked "Nihai Tüketici", up to 12,000 TL.

Do meal card payments become e-documents too? No. Meal cards and vouchers are a defined payment type in the system, but these payments are documented with a non-fiscal information slip rather than an e-document.

Whether you choose GMÖEBYS or stay with a fiscal cash register, the real operational question is the same: will your order lines be retyped into documents, or flow automatically? dojofood POS's Pavo fiscal cash register integration automates that flow on the cash register side; its e-Adisyon integration is live, and QR menu ordering plus recipe-based inventory are part of the same system. dojofood is not an operator institution; a GMÖEBYS application always goes through a GİB-licensed operator.

Official sources

• VUK General Communiqué No. 507 (Official Gazette 01.06.2019, no. 30791): the founding text of GMÖEBYS
• GMÖEBYS Application Guide, v1.0 (GİB, 06.07.2021): taxpayer application steps
• GMÖEBYS Application, Permission, Approval and Audit Processes Guide, v1.0 (GİB, 30.12.2019): operator institutions, the GMU, document and ownership rules
• About GMÖEBYS (GİB e-document portal)
• Operator Institution List (GİB; the official, current list of licensed operators)
• Digital Tax Office (application channel)
• 2026 invoice-issuance threshold (12,000 TL): VUK General Communiqué No. 588 (Official Gazette 31.12.2025, no. 33124, 5th repeated issue)

This content is for information purposes; consult your tax advisor or certified accountant for your specific situation.