SHANNON LIMITED LIABILITY COMPANY (“SHANNON”) released voicast, Conversational AI for Developers, on October 3, 2026.
Background
Booking and inquiry calls are still answered by staff who have to stop what they are doing. Nobody can pick up during treatment or while serving customers, and calls outside business hours are simply lost. Answering the phone is a heavy burden on the front line.
SaaS companies that provide booking and business systems hear from their customers that the product should handle phone calls too. But combining speech recognition, a conversational AI and speech synthesis, and getting what the caller said correctly into their own system, is a heavy engineering burden. Off-the-shelf AI phone services move the phone numbers and screens to that service, so they cannot be embedded in the SaaS’s own product.
We built voicast so that SaaS companies can add AI call handling to their own products while keeping their phone numbers, screens and customer contracts as they are, plugging in just the conversation through an API.
What voicast is
voicast answers phone, web and app audio in Japanese and other languages, collects what the caller needs and returns the result. The business sets the AI’s role (for example, a dental clinic receptionist), its greeting and tone, the details to collect, answers to common questions and the conditions for handing off to staff, and the AI follows these settings in the conversation, reading back what it heard to confirm.
It is headless: it has no screens or phone numbers and handles only the conversation, so the SaaS that integrates it decides the phone numbers, lines, screen design and what happens after the call.
- Conversations that follow a role and scenario. Speech recognition listens, an LLM decides the reply and speech synthesis speaks it. voicast collects name, callback number, reason for calling and your own fields. Settings are versioned, and a live call keeps the version it started with.
- Hand-off to staff. When the AI decides a hand-off condition is met, it ends the conversation and your SaaS transfers the call to a staff member’s phone.
- Answers to common questions. Set answers such as business hours, and voicast gives them on the spot.
- Results, transcripts and summaries. After each call, get the outcome, reason, collected fields, duration, transcript and summary through the API. Post-call notifications are sent as webhooks signed to the Standard Webhooks spec.
- In-call integrations. During the call the AI reads and writes booking systems, calendars and CRMs to check availability and make bookings. Google Calendar, Microsoft 365, Google Sheets, kintone, HubSpot and more are supported, and you can add your own API or MCP server. Summaries can be sent to Slack, Microsoft Teams, Chatwork and LINE WORKS after the call.
- A connect screen for each business. Embed in your product the screen where each business that takes the calls connects its own calendar and other accounts. Connection keys and agent settings are separate per business.
- Avatars. On the web and in apps, voicast can return replies as text only. Combined with avacast, SHANNON’s headless platform for avatar conversations, an avatar can talk with your customers following your scenario.
- Dashboard, API and MCP. Manage organizations, projects, live and test environments and API keys in the dashboard. Through MCP, AI agents such as Claude can work with agent settings and call results.
Intended uses
- Dental clinic phone bookings: taking and changing bookings and answering questions such as opening hours
- Real estate viewing requests: collecting the property and preferred time, then passing it on for a staff callback
- Restaurant reservations: collecting party size and preferred time and checking availability in the booking system
- First-line B2B support: collecting the company name and request, and handing off to staff when conditions are met
- After-hours reception: taking the caller’s request outside business hours for follow-up the next business day
Pricing
No monthly fee: you pay for the minutes you use. Phone and web or app sessions cost the same. Prices exclude tax.
| Plan | Price |
|---|---|
| Pay as you go | ¥6 per minute |
| High-volume contracts | Custom |
Usage is paid from prepaid credits, with auto-recharge when the balance runs low. Time runs from connect to hang-up, measured in seconds, and the monthly total is rounded up to the minute. Phone lines (numbers and carrier charges) are not included. Contract pricing is available for partners with large call volumes.
For developers
Phone calls connect their audio from Twilio TwiML, and web and apps connect over WebRTC. A REST API covers agent settings, businesses, call results and usage, and an MCP server is provided. Usage can be broken down by business, day or channel, so SaaS companies can bill their own customers.
Contact
For rollout and Enterprise contracts, use the contact form.
Official site: https://voicast.jp/en