SMS

Send and receive SMS messages via your provisioned Tone numbers.

Sending SMS

Response:

Receiving inbound SMS

Configure your number's SMS webhook URL in the dashboard. Tone will POST to that URL:

Rate limits

• 10 messages per minute per API key (sliding window, Upstash Redis)
• Exceeding the limit returns 429 Too Many Requests

Phone number validation

All to and from_number fields must be in E.164 format (e.g. +919876543210). Invalid numbers return 400.

Character limits

| Type | Characters | Segments | |---|---|---| | Standard GSM | up to 160 | 1 | | Long message | 161–1600 | multiple |

Tone supports up to 1600 characters (10 concatenated segments).

Retrieving logs