Zadarma → VAPI SIP integration
# supportb
bsbrown_78
10/27/2025, 3:58 PMHi VAPI Team! 👋
Need help with Zadarma → VAPI SIP integration.
Setup:
- Number: +48 226 022 600 (Zadarma Poland)
- VAPI Phone ID: e7c87bc9-6b1c-4197-a4f5-fd1358010d65
- SIP URI set: sip:48226022600@sip.vapi.ai
- Assistant assigned: 72577c85-81d4-47b4-99b5-0ca8b6ed7a63
Problem:
Zadarma panel rejects all SIP URI formats with "not found" error.
Tested:
- sip:48226022600@sip.vapi.ai:5060 ❌
- sip:48226022600@sip.vapi.ai ❌
- 48226022600@sip.vapi.ai ❌
Questions:
1. What exact format should Zadarma use to forward to VAPI?
2. Does VAPI require IP whitelisting for Zadarma (sip.zadarma.com)?
3. Should I use BYO SIP Trunk instead?
4. Known compatibility issues with Zadarma?
Note: Twilio works fine with same assistant.
Thanks! 🙏
• VAPI SIP endpoint:
sip.vapi.ai:506048226022600v
Vapi Support Bot
10/27/2025, 4:00 PMThanks for the detailed info! To clarify, have you already created a SIP trunk credential in Vapi using your Zadarma SIP number and password, and then associated your Zadarma number with that credential in Vapi? This step is required for Zadarma integration to work correctly.
Let me know so I can guide you to the next step!
Sources:
- [Zadarma SIP Integration Guide](https://docs.vapi.ai/advanced/sip/zadarma)
- [SIP Trunking with Vapi](https://docs.vapi.ai/advanced/sip/sip-trunk)
b
bsbrown_78
10/27/2025, 4:04 PM48226022600@sip.vapi.ai:5060 also doesnt work
bsbrown_78
10/27/2025, 4:07 PMThanks for the quick response! I tried creating SIP trunk credential as you suggested.
Attempted:
{
"provider": "byo-sip-trunk",
"name": "Zadarma SIP Trunk",
"gateways": [
{
"ip": "sip.zadarma.com",
"port": 5060,
"inboundEnabled": true,
"outboundEnabled": false
}
]
}
Error:
"Couldn't validate SIP trunk credential. SIP gateway creation failed."
Questions:
1. Does VAPI need to be whitelisted on Zadarma's side for validation to pass?
2. Is there a way to skip validation and create credential anyway?
3. Should I contact Zadarma to allow VAPI IPs first?
4. Or is there a different gateway configuration needed?
Zadarma Details:
- SIP server: sip.zadarma.com:5060
- My SIP login: 862027
- Number: +48226022600
What's the next step? Thanks! 🙏
bsbrown_78
10/27/2025, 4:11 PMUPDATE to my previous message:
I also discovered all my calls are failing with:
pipeline-error-openai-401-incorrect-api-key
Even after switching models (tried GPT-4o, Claude), calls still fail.
This suggests:
1. Provider API keys not configured in my account?
2. Account-level configuration problem?
3. Organization settings issue?
ALL calls ending with 401 errors regardless of model.
Can you check my account configuration?
Org ID: 127f2206-851c-47b8-9de1-352e7bd58b3f
Thanks!
n
Nir Simionovich (CEO@Cloudonix)
10/27/2025, 7:00 PM@bsbrown_78 Add a + infront of the number
sip:+48226022600@sip.vapi.ai:5060Nir Simionovich (CEO@Cloudonix)
10/27/2025, 7:01 PMVAPI requires all inbound calls to follow the SIP Challenge/Response method. On your Zadarma SIP trunk, just add arbitrary username/password.
g
GIDEON
10/27/2025, 11:55 PM@bsbrown_78 If after pulling out the whole steps provided by the vapi support bot and you still couldn’t get a result then kindly reach out to me.
n
Nir Simionovich (CEO@Cloudonix)
10/28/2025, 10:39 AM@bsbrown_78 Basically, if you want to connect Zadarma in a more reliable and visible manner, contact me and I'll help you connect Zadarma via Cloudonix. This connection is more visible and provides more in-depth capabilities.
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