What Is Vapi? AI Phone Agent: Pricing, Turkish Numbers (BYO SIP), Turkish Language, n8n and KVKK

With Vapi you build an AI assistant that picks up the phone and talks: it answers questions, checks the calendar and books appointments through n8n, and transfers the call to a staff member when needed. When the call ends, a summary and the fields you defined (name, request, appointment time) arrive at your server in an end-of-call report.

Who it's for: Vapi positions itself for developers. The assistant can be set up from the dashboard, but connecting your own SIP line is done through the API, and setting up tools and reports requires technical knowledge. An agency or developer does the setup; the business uses the result.

Where it fits in DijiKoçum packages: the “inbound call voice agent” add-on module of the Business Communication Package (answers the business's landline or 0850 line, FAQ and appointments, transfer to a human, end-of-call report to n8n) and an optional module in the Appointment package.

An assistant has three swappable parts: transcription (turns speech into text, STT), the language model and voice (TTS). Vapi adds its own real-time layer in between: detecting when someone has finished speaking, telling interruptions apart, filtering background noise. This layer can't be configured and doesn't store audio.

1. 1Create an account Sign up at dashboard.vapi.ai; $5 in starting credit is added. The terms require you to be 18 or the age of majority.
2. 2Create an assistant Choose the transcription, language model and voice providers; for Turkish, pick a model and voice that support it (see the Turkish section).
3. 3Add tools Set the transfer number with Transfer Call and the n8n Webhook address with API Request.
4. 4Test it Try it from the dashboard with a web call or a simulation. The free Vapi number is US-only and for inbound calls only.
5. 5Connect the Turkish number Create the BYO SIP trunk credential and the number through the API (section below).
6. 6Set up the report Set the Server URL to the n8n Webhook address; define the Structured outputs schema.
7. 7Add credit Add a card under Billing, buy credit and turn on auto-reload if you like.

!Vapi's limits are per subscription, not per account: Usage only allows 2 organizations and 4 concurrent calls. An organization is a separate workspace; assistants, numbers and keys belong to the organization.

The free numbers Vapi provides are US numbers and take inbound calls only. For your landline or 0850 number in Turkey, you get a SIP trunk from your carrier (such as NetGSM or Verimor): a virtual line that connects your phone line to another system over the internet. Vapi calls this a “Custom BYO SIP Trunk” and charges nothing for SIP transport; carrier fees are separate.

1. 1Get the details from your carrier The SIP server address, username and password (or IP authentication), and at least one number.
2. 2Create a SIP trunk credential Send a request to the Vapi API with provider: byo-sip-trunk: put the carrier's SIP address in gateways and the username and password in outboundAuthenticationPlan; save the returned Credential ID.
3. 3Connect the number Send the number and the Credential ID with provider: byo-phone-number; assign the assistant to the number.
4. 4Route inbound calls In the carrier's panel, route calls to {number}@{credential_id}.sip.vapi.ai. Add Vapi's signaling IPs (44.229.228.186, 44.238.177.138) to the allowlist; for audio, UDP 40000–60000.
5. 5Test it Start an outbound call through the API, and call the number from outside to test inbound calls.

Vapi doesn't recommend IP-based authentication because its servers are shared with many customers: calls can be misrouted. If your carrier offers username and password authentication, use that. To transfer a call to a human with SIP REFER, REFER may need to be enabled at the carrier.

How to get a SIP trunk and an 0850 number at NetGSM →

This section is not an official source; it's the method followed in DijiKoçum setups.

• Keep the system prompt short: who it is, what it does, what it doesn't do, when to transfer.
• Keep the opening announcement fixed: “This call is being recorded; I'm X's AI assistant.”
• Always keep transfer to a human available; test direct transfer on your own SIP line first.
• Don't bake information like appointments and prices into the prompt; read it live from n8n with API Request.
• Don't collect sensitive information over the phone; if you must, use a separate assistant that turns off recording and logs for that step.

In Vapi the per-minute cost is made up of four items plus Vapi's hosting fee. The official FAQ: transcription, language model, voice and transport are passed through at the provider's list price with no markup; on top comes Vapi's fee of $0.05 per minute. You use prepaid credit.

The calculator on the pricing page shows roughly $82–$129/month for 1,000 minutes (about $0.08–$0.13 per minute). No package is mandatory; the Core package is $29 a month (10 concurrent calls, 30-day data retention, a zero data retention option, email support), and Pro is 10% of the hosting fee, at least $999/month.

Refunds: Under the terms, per-minute and usage-based fees are considered “earned as incurred” and are not refunded except where required by law. For non-usage packages, refunds are at Vapi's discretion, prorated by remaining days. Prices are in US dollars; the pricing page doesn't say whether VAT applies.

Official pricing page last checked on October 28, 2026.

Turkish support depends on the provider and model: make sure the transcription model and voice you choose are marked in the Turkish column. You can also connect a custom or cloned voice from your own ElevenLabs account using its API key and voice ID.

!If you'll make outbound (campaign) calls: in Turkey, Law No. 6563 treats commercial messages sent by phone, call center or automated dialing machine as “commercial electronic messages” and requires prior consent; İYS (Turkey's commercial message consent registry) keeps consent for the call channel separately. Messages can be sent to tradespeople and merchants without consent. Vapi's outbound calling doc also reminds you that automated calls without consent are illegal in the US, and the terms prohibit unlawful use. Answering inbound calls is not covered by this.

Vapi$0.05/min platform + provider costs; with your own key you pay the provider directly; 4 concurrent calls included; EU region only on Premier.Retell AINo monthly fee, $0.07–$0.31/min; 20 concurrent calls included; no telephony fee on your own SIP line; you connect the SIP line from the dashboard.

Differences according to the docs: Vapi passes each item through separately at the provider's price and accepts your own API key; Retell gives a bundled per-minute price. In Vapi your own SIP line is connected through the API, in Retell from the dashboard. Raw data retention is 14–180 days in Vapi depending on the package, and indefinite by default in Retell (configurable). Both offer Turkish voices and transcription, webhooks and an n8n connection.