A Czech number for your voice agent
Voice agent platforms don't sell Czech or Slovak numbers, so you have to bring one. At volai you get a Czech number right away for 25 CZK per 30 days and point it at your platform's SIP address.
Who this is for
Your agent is on ElevenLabs
Bring the number in as a SIP trunk. We have verified inbound and outbound calls live, step by step in the ElevenLabs guide.
Your agent is on Vapi
Bring the number in through a BYO SIP trunk, with no login details. We have verified inbound calls live, outbound not yet. The setup is in the Vapi guide.
Your agent is somewhere else
Retell, Bland or your own PBX: other platforms go through a generic SIP trunk, see the SIP documentation. We have verified the procedure for ElevenLabs and Vapi only, so make a test call on anything else. Synthflow accepts a number over SIP on its Enterprise plan only.
1Create an account and get 50 CZK in credit
Sign up at volai.cz. After you verify your e-mail, 50 CZK lands on your account and you don't need to enter a card.
2Pick a number from the pool
In the portal (Numbers) or through the API, take a Czech number from the pool: Prague, Brno or non-geographic 910. It is yours right after you buy it and costs 25 CZK per 30 days. A number from another region is ordered with your address in the Czech Republic, and the Slovak number is a Bratislava +421 2 one only.
3Route the number to your platform's SIP address
Switch the number to SIP mode and set your platform's SIP address as the destination. The exact address format and the platform settings are in the ElevenLabs and Vapi guides.
curl -X PATCH "https://volai.cz/v1/numbers/+420601234567" \
-H "Authorization: Bearer vk_YOUR_KEY" \
-H "Content-Type: application/json" \
-d '{"routing": {"mode": "sip", "sipUri": "sip:+420601234567@YOUR_PLATFORM_SIP_ADDRESS"}}'Ways to get a Czech number
ElevenLabs, Vapi, Retell, Bland and Synthflow don't sell Czech or Slovak numbers: you buy one from a carrier and the platform just accepts it. These are the ways we have checked. Each wants different documents and takes a different time.
| Way to get it | Documents and address | Wait | Number per month | Inbound minute | Fits when |
|---|---|---|---|---|---|
| volai | Documents and addressPool numbers (Prague, Brno, 910): no documents, just an e-mail and a verification code; credit is topped up by card. Other regions are ordered with your address in the Czech Republic. | WaitRight after purchase | Number per month25 CZK / 30 days | Inbound minute0.50 CZK | Fits whenYou want the number right away, without documents, in koruna on one account with a call history. |
| Twilio, national number +420 910 | Documents and addressNo documents, an address from any country. Voice only. | WaitNot verified | Number per month34.50 CZK (USD 1.50) | Inbound minute0.25 CZK (USD 0.0107) | Fits whenYou can handle a second account and talk roughly 40 inbound minutes a month or more. |
| Twilio, geographic number | Documents and addressAn address in the number's area and a document proving it; a company needs a registry extract. | WaitDocument review, usually up to 3 business days | Number per month34.50 CZK (USD 1.50) | Inbound minute0.25 CZK (USD 0.0107) | Fits whenYou have an address in the number's area and want a geographic number straight from Twilio. |
| Telnyx, geographic number | Documents and addressID, proof of address not older than 3 months, and being physically in the Czech Republic when you buy. | WaitNot verified for Czechia, generally days | Number per month23 CZK (USD 1) + 23 CZK setup | Inbound minute0.14 CZK (USD 0.006) | Fits whenYou are in the Czech Republic, have the documents and watch the minute price. |
| Zadarma, city number | Documents and addressAn address in the number's region; your details are verified before activation. | WaitAfter verification | Number per monthfrom about 40 CZK (EUR 1.6), 6-month subscription | Inbound minuteFree per its price list, rate not verified | Fits whenYou have an address in the number's region and don't mind a six-month subscription. |
| peoplefone, Czech number | Documents and addressCommercial register extract, proof of address in the Czech Republic and ID of the signing person. | WaitOrder on request, answer within 24 hours | Number per monthCHF 10 | Inbound minuteNot verified | Fits whenYou are a company based in the Czech Republic. |
The data on the platforms and number providers comes from their public pages, checked on 16 Oct 2026. Prices exclude VAT, are converted at 23 CZK per USD and 25 CZK per EUR, and change; check with the provider before you order. "Not verified" means we could not find the figure.
Step-by-step guides
Frequently asked questions
- Can I receive SMS on this number?
- No. A voice number (landline or VoIP) doesn't receive SMS. For receiving SMS there is the SMS number add-on: a separate Czech mobile number for SMS only at 390 CZK per 30 days, receiving included. We don't guarantee verification codes from services; the number is for texting with people. You can send SMS through the REST API (
POST /v1/messages) without it, at 1.36 CZK per segment, but the recipient can't reply. - Can I get a Slovak number too?
- Yes, a Bratislava +421 2 one. It is a mediated foreign number and the stock is replenished by hand, so it may not be available right away. The price of the number is the same as for a Czech one, 25 CZK per 30 days, but it is paid three months ahead (75 CZK).
- What if my platform asks for login details?
- For inbound calls, ElevenLabs (imported as a SIP trunk) and a BYO trunk in Vapi ask for no login details: they recognise our calls by an IP address from the range
81.31.45.0/24, which you allow inallowed_addresses, or ingatewaysfor Vapi. A username and password even break the call in Vapi, which is why volai doesn't save them for a<credentialId>.sip.vapi.aiaddress. The outbound trunk in ElevenLabs, on the other hand, does need your line's credentials; you find them in the ElevenLabs guide. If your PBX challenges the call with a login (401 or 407), addsipUsernameandsipPasswordto the routing; that only works against a target that sends the challenge and accepts the credentials. Details are in the SIP documentation. - How does my agent call out from the Czech number?
- Through a relay. Most platforms can't register a line permanently, they only send a one-off authenticated call. So right before the call you create a short-lived relay connection (
POST /v1/relay) and give the platform thesipName, or thesipUri. An outbound minute costs 0.92 CZK, and no agent surcharge applies. We have verified ElevenLabs live, Vapi not yet; the procedure is in the ElevenLabs guide. - Is volai the cheapest way to a Czech number?
- No, it is the easiest. Above roughly 40 inbound minutes a month, the national +420 910 number at Twilio (34.50 CZK (USD 1.50) for the number and 0.25 CZK (USD 0.0107) per minute, at 23 CZK per dollar) works out cheaper than volai (25 CZK and 0.50 CZK per minute). Telnyx is cheaper on minutes, but wants documents and you in the Czech Republic in person. volai wins by giving you a pool number right away, without documents, in koruna and with calls on one account. The data on other providers is from 16 Oct 2026 and changes.