Integrations & Telephony
Twilio, SIP trunks, CRMs, helpdesks, calendars — connecting voice agents to the systems your business already runs.
18 articles
How to Integrate Voice Agents with a Custom REST API
Most voice agent integrations are with off-the-shelf systems — Salesforce, HubSpot, Zendesk, Stripe. But eventually every production deployment needs to integrate with a custom internal API — the billing system, the proprietary order management, the ops dashboard that only your…
Sending Voice Agent Transcripts to Slack
Slack is where most teams live in 2026, and for voice agent deployments, getting call transcripts and key events into Slack closes a critical ops loop. Escalations land in the right channel with context. QA reviews happen where the team already works.
Connecting Voice Agents to Snowflake or BigQuery
Voice agent deployments generate a lot of data. Every call produces a transcript, metadata (duration, outcome, caller info), function-call traces, sentiment signals, and operational metrics.
How to Port a Phone Number to Your Voice Agent
You already have a phone number that customers know. Your main line, published on your website, business cards, Google. You can't afford to change it.
Setting Up Toll-Free Verification for AI Calling
Toll-free numbers (800, 888, 877, 866, 855, 844, 833) carry a compliance requirement that catches many voice AI deployments off-guard: before you can reliably send SMS or initiate high-volume outbound voice traffic from a toll-free number, you need carrier verification.
SIP vs WebRTC for Voice Agents
SIP and WebRTC are the two dominant technologies for real-time voice in 2026. Most voice agent deployments use one, the other, or both. Deciding which to use for a given integration depends on where the call originates, what network conditions you expect, and how much control…
How to Use Twilio Studio with AI Voice Agents
Twilio Studio is Twilio's visual flow builder for call (and SMS) workflows. It lets you drag-and-drop a call flow — gather digits, branch on logic, route to agents, trigger webhooks — without writing code.
Bring Your Own Twilio: Pros, Cons, and Setup
Bring Your Own Twilio (BYO) is the architecture where your voice agent platform (Vapi, Retell, Simba, SIMBA) connects to your Twilio account rather than using the vendor's managed Twilio setup.
Connecting Voice Agents to Stripe for Payments
Taking payments over the phone is a workflow that voice agents get asked to handle constantly — bill payments, copays, service fees, subscription changes, you name it.
Sending SMS Follow-Ups from Voice Agents
SMS follow-ups are one of the highest-ROI additions to any voice agent deployment. The caller just had a conversation; they know the appointment time, the tracking link, the next step. But people forget.
Calendar Integrations: Cal.com, Google, Outlook
Voice agents that book, reschedule, or cancel appointments live or die on their calendar integration. A voice agent that guesses at availability or writes to the wrong calendar breaks the workflow it was built for.
Webhooks 101 for Voice Agents
Webhooks are the backbone of voice agent integrations. When your voice agent needs to call a CRM, update a ticket, send an SMS, or trigger any external action, it does so via HTTP — and most of those HTTP calls are structured as webhooks or webhook-like REST operations.
Connecting Voice Agents to Zendesk
Zendesk is the dominant ticketing and support platform for mid-market and enterprise customer service, and it's where most voice agent-handled support interactions need to land.
Connecting Voice Agents to Intercom
Intercom is the messaging-first customer communication platform that a lot of SaaS companies run their support on. Historically chat-centric, it's expanded to cover email, a light voice layer, and AI-native tools (Fin).
Connecting Voice Agents to HubSpot CRM
HubSpot is the CRM of choice for a large share of SMB and mid-market SaaS companies, and increasingly for mid-market customers in other verticals. Its API is cleaner than Salesforce's, its data model is simpler, and integrations are generally less painful.
Connecting Voice Agents to Salesforce CRM
Salesforce is the de facto CRM for most mid-market and enterprise companies deploying voice AI. If your agent is doing anything meaningful in a business context — handling sales inquiries, supporting customers, qualifying leads, processing orders — there's a good chance the…
SIP Trunking 101 for Voice Agent Builders
SIP trunking is the unsexy plumbing that makes voice agents work at scale. It's the protocol and infrastructure that lets calls move between the public phone network and your voice AI without relying on a telephony provider's proprietary APIs.
Twilio + Voice Agents: A Complete Guide
Twilio is the dominant telephony backbone under most voice agent deployments. If you're building on Vapi, Retell, Simba, OpenAI Realtime, or SIMBA, odds are your calls flow through Twilio at some point.