What Is Netgsm? Turkish Landline and 0850 Numbers, Connecting a Voice Agent via SIP, SMS, Pricing and İYS

Netgsm is not an AI tool but a telephone operator. Voice agent platforms (Retell, Vapi) provide the AI but don't give you a Turkish number; you get the 0212, 0312 or 0850 number your customers will call from a Turkish operator. Netgsm provides that number and routes incoming calls to the voice agent via SIP. SIP (Session Initiation Protocol) is the standard method for carrying phone calls over the internet.

Who it is for: businesses in Turkey that want AI to answer their phone or want to send appointment reminder SMS. As a local alternative, Verimor (verimor.com.tr) also provides numbers, a cloud PBX and SMS.

Netgsm's own Retell and Vapi guides state that no PBX is needed for basic use. You add the PBX (Netsipp; called Netsantral, its former name, in the knowledge base) when you need after-hours routing, transfers or IVR.

Number types: geographic numbers with the area codes of all 81 provinces, and 0850. An 0850 number can receive unlimited simultaneous incoming calls and incoming calls are free of charge. A geographic number is assigned based on the address you enter in your application. 0800 (toll-free) numbers also exist; connecting them to an external platform via SIP is not described separately on the official pages, so ask customer service.

1. 1Start the application netgsm.com.tr › Üyelik (Membership) › Kurumsal Sabit Telefon (Business Landline) › Yeni Abonelik (New Subscription). Enter your first name, last name and mobile number; verify with the code you receive.
2. 2Authorized person Choose the service and organization type; enter the Turkish national ID number, date of birth, mobile number and email of the person who will sign the contract.
3. 3Address Enter the address where the subscription will be set up; the geographic number is chosen based on this address.
4. 4Number Choose the number type (geographic or 0850) and the area code, and complete the application.
5. 5Contract, documents, payment Log in to Online İşlemler (Netgsm's online account area) with the username sent by SMS; approve the contract, upload the documents and pay. Approval via e-Devlet requires an NFC-enabled phone and a chip ID card.

!Netgsm's document list only covers businesses and organizations (sole proprietorships, companies, associations, foundations, municipalities…). Whether an individual without a tax certificate can subscribe is not clear in the official sources; ask at 0850 303 0 303 before applying. If a proxy applies, a power of attorney is also required.

1. 1Define a SIP Trunk on the voice agent platform Enter Netgsm's SIP server address (sip.netgsm.com.tr), the SIP username and password; write the number with +90. This information is in Netgsm Web Portal › Ses Hizmeti (Voice Service) › Ayarlar (Settings) › SIP Bilgileri (SIP Information).
2. 2Create the agent and assign it to the number Set up the voice assistant on the platform and link this number to it in the incoming call settings.
3. 3Enable SIP Trunk on the Netgsm side In Ses Hizmeti (Voice Service) › Ayarlar (Settings) › SIP Bilgileri (SIP Information), enable SIP Trunk; enter the platform's SIP address as the destination (sip.vapi.ai for Vapi), port 5060, and save.
4. 4Prefix settings Choose caller prefix 0 (default) and called prefix +90; save the prefix settings.
5. 5Test Call your number; the call should reach the AI.

Guide to setting up the number and voice agent in Retell →

Guide to setting up the number and voice assistant in Vapi →

!The SIP domain that Retell asks you to enter in Netgsm may change; get the current one from Retell. Netgsm's pages say nothing about IP restrictions or BTK rules for routing to servers abroad. Whether SIP Trunk Forwarding has a separate fee is also not on the pricing page; ask customer service before enabling it.

Netgsm has an official node (ready-made connector) for n8n: @netgsm/n8n-nodes-netgsm on npm. It sends SMS, checks delivery status, receives incoming SMS, adds numbers to İYS and checks consent. It is used without writing code, by filling in a few fields.

1. 1Open a workflow in n8n, search for "Netgsm" in the node panel and install the node.
2. 2In the credentials, enter your subscriber number as the username and the password of the API sub-user you created in Netgsm as the password.
3. 3Trigger: a new appointment in your calendar or CRM. Have the Netgsm node send the customer a confirmation SMS.
4. 4Use a scheduler to send a second reminder 24 hours before the appointment; check İYS consent before any message with promotional content.

For developers, the SMS and landline API docs are at netgsm.com.tr/dokuman; the official JS client on npm is @netgsm/sms.

The voice and SMS pricing pages state that 10% ÖİV (Turkey's special communications tax) and 20% VAT (KDV) are included; the Netsipp package prices carry no tax note (on the same page only the voice-recording items say “all taxes included”), so ask when getting a quote. Payment is by credit card, bank transfer (havale/EFT) or automatic payment.

Canceling: the subscription is canceled via Online İşlemler, the Netgsm Hesabım app or e-Devlet; it closes within 24 hours after checks. The number page states that the remaining months paid for the package are refunded; minute and SMS bundles are non-refundable.

Official pricing page last checked on October 28, 2026.

!This section is general information, not legal advice. For your specific situation, ask a lawyer or a KVKK consultant.