Open for JustCall

JustCall is a closed cloud phone system — there's no externally exposed SIP. The integration pattern is forwarding: in your IVR (or via team overflow / after-hours rules) you forward specific calls to an external phone number that Open answers. JustCall stays in charge of users, numbers, dialer, and the dashboard.

Practically, you provision an Open inbound number, then add it as a forwarding destination in JustCall. The IVR can pass the original caller's number through so the AI knows who it's talking to. Only the specific calls you've routed to AI take the detour; the rest keep flowing to your JustCall team unchanged.

What the AI does on the call: it greets, listens, reasons over your knowledge base and the tools you've connected (HubSpot, Salesforce, Pipedrive, Zendesk — plus the JustCall API for contact lookups), and acts. When the AI needs a human, it warm-transfers back to your JustCall team via PSTN bridge with the live transcript and detected intent attached.

JustCall's analytics keep working for the legs JustCall handled. Open adds AI-side reasoning traces, transcripts, and outcome tags on its side, so you can compare resolution rate and AHT between human and AI.

Billing stays predictable. JustCall continues to invoice your seats and the minutes for the legs it handles. Open charges per resolved conversation, no markup, no extra JustCall seats.