DOCUMENTATION

Build on Express IVR.

Everything you need to go from your first API call to a production call flow — voice, messaging and AI on one runtime.

Overview

Express IVR is one cloud runtime for voice, IVR, messaging and conversational AI. You design a flow once — greeting, routing, AI and channels — and it runs across calls, WhatsApp, SMS and RCS with a single customer thread and one set of analytics.

These docs walk you from your first API call to a production call flow. If you prefer to talk it through, book a demo and we'll build your first flow live.

Quickstart

Make your first call or message in under five minutes with a single API request.

Flow builder

Drag-and-drop greeting, gather, routing and AI nodes — versioned and reversible.

AI packs

Switch on Voice, Chat, Text or Quality and attach them to any branch of a flow.

Quickstart

Place your first outbound call. Replace the API key and numbers with your own.

# Place a call that plays a message
curl https://api.expressivr.com/v1/calls \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d from="+918047182200" \
  -d to="+9199XXXXXXXX" \
  -d flow_id="flw_welcome"

Authentication

All requests use a secret API key sent as a Bearer token in the Authorization header. Create and rotate keys from the dashboard. Keep keys server-side — never ship them in a browser or mobile app.

Core concepts

  • Number — a virtual, toll-free or vanity number that receives and places calls.
  • Flow — the logic a call or message runs through: greeting, gather, route, connect.
  • Widget — a single step in a flow (e.g. gather_input, connect_to_team).
  • Thread — one customer conversation across voice, WhatsApp, SMS and RCS.
  • Event — a webhook fired at each hop so your systems stay in sync.

Build a call flow

A typical inbound flow: a branded greeting, a gather step that accepts a keypress or spoken intent, a split that routes on the result, and a connect to the right team — with a voicemail fallback. Publish is diffed and reversible, and you can A/B two flows against live traffic.

Channels

Voice

Numbering, routing, recording and neural TTS.

SMS

DLT-ready transactional and promotional routes.

WhatsApp

Business API with templates, media and two-way chat.

RCS

Rich cards, carousels and read receipts.

AI packs

AI packs are modular. Attach the Voice Pack (ASR + neural TTS), Chat Pack (NLU bots), Text Pack (intent-aware SMS/RCS) or Quality Pack (100% call scoring) to any flow — no re-platforming.

Webhooks & events

Subscribe to events such as call.initiated, call.completed, message.delivered and flow.branch. Express IVR POSTs a signed JSON payload to your endpoint; verify the signature header before trusting it.

SDKs & libraries

Official helper libraries are planned for Node.js, Python, PHP and Java. Until then, the REST API works with any HTTP client — see the API reference.