Vonage

What you can build

• Send a delivery ETA on the customer's channel

  A driver's ETA becomes a proposed WhatsApp or RCS message with SMS failover. You approve; the status webhook records submitted and delivered against the stop.

  With ETA Notice

• Confirm appointments and read the replies

  The operator drafts a reminder with a client_ref tied to the booking and proposes it. A reply through the Inbound Message webhook lands on the same record for a person to act on.

  With Appointment Reminder

• Tell a customer about a backorder

  When an order line cannot ship, the operator proposes an SMS with the new date. Rejected or undeliverable statuses are surfaced so a person can try another channel.

  With Backorder Notice

• Answer where-is-my-order by text

  An inbound SMS asking about an order is matched to the order, and a proposed reply with the tracking status is drafted for approval.

  With WISMO Deflection

Requirements

• A Vonage API account with an API key and secret from the API Dashboard
• A Vonage Application with inbound and status webhook URLs set, plus its application id and private key for JWT auth
• A Vonage number or sender id per channel; WhatsApp, Messenger, and Viber accounts are linked through the External Accounts API
• 10 DLC brand and campaign registration before sending SMS or MMS from a US 10-digit long code
• Phone numbers as E.164 digits with no leading + or 00

Authentication

Basic authentication with the account API key and secret, or a JWT signed with a Vonage Application's private key and application id and sent as a Bearer token; Vonage recommends JWT beyond the Messages Sandbox.

Limits

• 75 requests per second per API key by default; above that the API returns 429
• A 202 means accepted by Vonage, not delivered; channel or network rejections arrive later as a rejected status
• SMS text is limited to 3200 characters and client_ref to 100; delivery is attempted for 72 hours by default, less on many operators
• Outbound WhatsApp status cannot be changed through PATCH; only inbound read receipts and RCS revocation are supported

Questions and answers

Which channels can receive inbound messages?

SMS, MMS, RCS, WhatsApp, Facebook Messenger, and Viber Business Messages deliver replies to the Inbound Message webhook set on your Vonage Application. Which media types arrive inbound varies by channel; SMS carries text only.

How do I know a message was delivered?

The send returns 202 with a message_uuid. Delivery is reported later to the Message Status webhook, per message if you set webhook_url in the request, with status submitted, delivered, rejected, or undeliverable, a timestamp, and your client_ref. The legacy SMS API uses separate Delivery Receipts instead.

Basic auth or JWT?

Both work. Basic uses the API key and secret and authenticates at account level. A JWT is generated from a Vonage Application's id and private key and authenticates at application level, which is needed for application webhooks and Secure Inbound Media. Vonage recommends JWT beyond the Messages Sandbox.