SMS Provider Send

Send a single SMS message to a phone number. This is the atomic send operation that all SMS drills chain together.

Tool Options

Twilio (Default Stack)

API Endpoint: POST https://api.twilio.com/2010-04-01/Accounts/{AccountSid}/Messages.json

Authentication: HTTP Basic Auth with Account SID and Auth Token. Store as environment variables TWILIO_ACCOUNT_SID and TWILIO_AUTH_TOKEN.

Request:

curl -X POST "https://api.twilio.com/2010-04-01/Accounts/$TWILIO_ACCOUNT_SID/Messages.json" \
  --data-urlencode "From=$TWILIO_PHONE_NUMBER" \
  --data-urlencode "To=+1234567890" \
  --data-urlencode "Body=Your message here" \
  -u "$TWILIO_ACCOUNT_SID:$TWILIO_AUTH_TOKEN"

Response (200):

{
  "sid": "SMxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
  "status": "queued",
  "to": "+1234567890",
  "from": "+10987654321",
  "body": "Your message here",
  "date_created": "2026-03-30T12:00:00Z",
  "price": null,
  "error_code": null
}

Node.js SDK:

const twilio = require('twilio');
const client = twilio(process.env.TWILIO_ACCOUNT_SID, process.env.TWILIO_AUTH_TOKEN);

const message = await client.messages.create({
  body: 'Your message here',
  from: process.env.TWILIO_PHONE_NUMBER,
  to: '+1234567890',
  statusCallback: 'https://your-webhook.com/sms-status'
});

Error Handling:

• 21211 — Invalid "To" phone number. Validate E.164 format before sending.
• 21610 — Recipient opted out. Do NOT retry. Mark contact as opted-out in CRM.
• 21612 — "From" number not SMS-capable. Verify number capabilities in Twilio console.
• 30004 — Message blocked by carrier. Likely spam filtering. Review message content for spam triggers.
• 30008 — Unknown error. Retry with exponential backoff (max 3 retries, 5s/15s/45s delays).

Salesmsg

API Endpoint: POST https://api.salesmessage.com/v1/messages

Authentication: Bearer token via Authorization: Bearer {api_key}. Obtain API key from Salesmsg dashboard > Settings > API.

Request:

curl -X POST "https://api.salesmessage.com/v1/messages" \
  -H "Authorization: Bearer $SALESMSG_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"to": "+1234567890", "text": "Your message here", "from_number": "+10987654321"}'

OpenPhone (Quo)

API Endpoint: POST https://api.openphone.com/v1/messages

Authentication: Bearer token via API key from Quo dashboard.

Request:

curl -X POST "https://api.openphone.com/v1/messages" \
  -H "Authorization: Bearer $OPENPHONE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"from": "phone_number_id", "to": ["+1234567890"], "content": "Your message here"}'

Heymarket

API Endpoint: POST https://api.heymarket.com/v1/messages

Authentication: Bearer token. Obtain from Heymarket > Settings > API Keys.

SlickText

SlickText does not offer a direct send API for 1:1 outbound. Use their campaign API for bulk sends or integrate via Zapier webhook for individual messages. Better suited for opt-in marketing campaigns than cold outbound.

Message Constraints

• SMS segment = 160 GSM-7 characters or 70 UCS-2 (Unicode) characters
• Messages exceeding one segment are split and billed as multiple messages
• Keep outbound prospecting messages under 160 characters for cost efficiency and readability
• Include opt-out language in first message to a new contact: "Reply STOP to opt out"

Pricing Reference

• Twilio: $0.0079/SMS + carrier fees (~$0.003-0.005/msg) = ~$0.011-0.013/msg effective (https://www.twilio.com/en-us/sms/pricing/us)
• Salesmsg: From $25/mo for 250 credits (https://www.salesmessage.com/features/new-salesmsg-pricing)
• OpenPhone (Quo): $15/user/mo includes unlimited SMS; API sends $0.01/msg (https://www.quo.com/blog/quo-pricing/)
• Heymarket: Per-user plans starting ~$20/user/mo (https://www.heymarket.com/pricing/)
• SlickText: From $29/mo for 500 texts (https://www.slicktext.com/pricing)