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Quick answers to common questions. Click any question to expand the answer, or follow the link to the full article for more detail.

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Account & Billing

No. Trial numbers are sandboxed for outbound testing only - no inbound routing until you complete KYC verification and purchase a dedicated DID. To unlock inbound calls, complete KYC in your dashboard (GST for organizations, Aadhaar/PAN for individuals), then purchase a dedicated incoming trunk.Read full article
Yes. Log in to the console, go to Account Settings → Limits, and purchase a higher concurrency or CPS ceiling directly through the billing portal. Changes take effect immediately.Read full article
Yes - 1400, 1600, and 92-series numbers are available. These require additional KYC and carrier approval. Contact support with your use case to initiate provisioning.Read full article

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API & Limits

You’ve hit either your Concurrency limit (too many simultaneous active calls) or your CPS limit (initiating calls too fast). Check your current limits in the console under Account Settings. Fix by throttling your dialer or purchasing a higher limit.Read full article
Concurrency is the maximum number of simultaneous active calls on your account at any moment. If your limit is 10 and 10 calls are live, an 11th attempt returns a 429 or SIP 503 immediately. Calculate your needs based on average call duration × calls per hour.Read full article
CPS governs how fast you can initiate calls - independent of concurrency. CPS of 1 means one new call per second. Even with free concurrency slots, blasting 5 calls in the same second with CPS=1 fails 4 of them. Use a pacing queue in your dialer to stay under the limit.Read full article
486 Busy Here - the callee is on another call or rejected the call. 480 Temporarily Unavailable - the device is off, out of range, or in airplane mode. If you see these repeatedly across many numbers on one carrier, that carrier’s spam filter may have blocked your caller ID - pause dialing and contact support.Read full article

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Features & Integration

Vapi, Retell AI, LiveKit, ElevenLabs, Pipecat, Bolna, Ultravox, and OpenAI Realtime - all via SIP trunk or WebSocket streaming. Standard SIP interoperability with Asterisk, FreeSWITCH, Teams, and Cisco PBX systems. See the Integrations section for step-by-step guides.Read full article
Yes - three methods: (1) <Dial> XML tag for warm/cold bridge transfers; (2) REST API transfer to redirect a live call to a new XML application mid-call; (3) SIP REFER (RFC 3515) for PBX-native blind or attended transfers.Read full article
Yes. Build IVR flows using <Gather> for DTMF and speech input, <Speak> for TTS prompts, and <Play> for pre-recorded audio. Your backend returns XML from a webhook - no drag-and-drop constraints.Read full article

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Trust & Support

Organizations: valid GST certificate (+ authorized signatory in some cases). Individuals: Aadhaar card + PAN card. Documents are encrypted at rest and only used for telecom regulatory compliance - not for any secondary purpose.Read full article
Open the support chat in the console, or email support@vobiz.ai. For production incidents include your requestId from the error response to speed up diagnosis.Read full article

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Browse all topics

Trial number inbound

Why trial numbers can’t receive inbound calls and how to unlock them.

Purchase Concurrency / CPS

How to scale up concurrent channels and calls-per-second limits.

1400 / 1600 / 92 numbers

Premium and short-code number provisioning availability.

429 errors

Diagnosing rate-limit and concurrency rejections.

Concurrency

Simultaneous-call limits and how to size them.

CPS

Calls-per-second pacing and queue strategies.

SIP 480 / 486

Distinguishing busy / unavailable / spam-blocked calls.

Integrations

Supported AI agents, SIP providers, and PBX bridges.

Call transfer

Dial XML, REST transfer, and SIP REFER methods.

IVR support

Build branching menus with Gather, Speak, and Play.

Verification documents

KYC requirements for organizations and individuals.

Contact support

How to reach our team and what to include in tickets.

Domestic calling in India

Caller-ID, media anchoring, and KYC requirements.

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Still have questions?

Our support team is here to help with anything not covered above. Contact support.