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Programmable SMS API · live on Free

Programmable SMS, with managed provider routing.

Send transactional SMS through a Senddio-provisioned number. The same /v1/send endpoint used for email accepts an SMS-specific payload and routes it through managed Telnyx infrastructure.

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● Free forever · No card · All 6 channels · AI credits
POST /v1/send · channel: sms
202 Accepted
curl https://api.senddio.com/v1/send \
  -H "Authorization: Bearer sdo_live_…" \
  -H "Content-Type: application/json" \
  -d '{
    "channel": "sms",
    "from":    "+14155552671",
    "to":      "+14155550123",
    "body":    "Your order #A-7714 shipped — track at sndd.io/t/abc",
    "tag":     "shipping"
  }'

# → 202 Accepted · { "id": "sdo_msg_…", "status": "queued" }
Channel
SMS
Telnyx (managed for you)
Free plan
10/mo
sampler limit
Same endpoint
/v1/send
POST · Bearer auth
Acceptance
202
queued, not delivered
How it works

SMS, made boring on purpose.

Use a provisioned sender, send a validated request, and follow provider delivery events in one dashboard. Destination and registration requirements still apply.

01
Step 01
You provision a sender.
Senddio provisions and pays for one managed sender number. Provide the business information needed for carrier registration and verify the business contact mobile. Use E.164 numbers for recipients.
02
Step 02
You write the message.
One line of body text. Same endpoint as your email. No SDK switch.
03
Step 03
We queue delivery.
Telnyx dispatches the message. Carrier policies and destination availability determine final delivery.
04
Step 04
You monitor delivery.
Provider delivery events update Logs. Inbound managed SMS replies are not currently part of this integration.

One endpoint, one key, one bill. That is all.

The shift

Manage the sender. Ship the message.

  • Keep sender registration requirements visible during setup.
  • No more managing a separate SMS provider integration.
  • No more skipping SMS tests because they cannot run in CI.
  • No more “where is my order?” landing in your support inbox.

One sending API, with provider delivery status in Logs.

Beyond the obvious

Whatever your team can imagine, this endpoint will send.

Real teams ship sms on Senddio for everything from order receipts to late-night customer apologies. Here are a few of the things they have built — and the kinds of things your team will dream up next month.

OTP that lands before the user looks upPassword reset for an account they forgotFraud alert before the second swipeAppointment reminder 24h, then 1h beforeShipping ETA with the driver's first nameFlight delay before the airline tells themRide-arriving ping when the car turns the cornerPrescription refill, ready for pickupHotel check-in code at 2:59pmEvent ticket QR for the doorLock combination for the cabin, expires SundayOTP that lands before the user looks upPassword reset for an account they forgotFraud alert before the second swipeAppointment reminder 24h, then 1h beforeShipping ETA with the driver's first nameFlight delay before the airline tells themRide-arriving ping when the car turns the cornerPrescription refill, ready for pickupHotel check-in code at 2:59pmEvent ticket QR for the doorLock combination for the cabin, expires Sunday
Donation thanks within thirty secondsPayroll-deposit confirmation on the 1stLow-stock alert to the buyer, not the customerOn-call escalation when Slack got ignoredCustomer win-back from a churn-risk scoreDietitian reminder to drink water at 11amAgent triage handoff to a human on SaturdayPolling-place reminder on election morningClass cancelled, refund coming, sorryLottery winner notification (we hope)AI shipping summary at end of dayDonation thanks within thirty secondsPayroll-deposit confirmation on the 1stLow-stock alert to the buyer, not the customerOn-call escalation when Slack got ignoredCustomer win-back from a churn-risk scoreDietitian reminder to drink water at 11amAgent triage handoff to a human on SaturdayPolling-place reminder on election morningClass cancelled, refund coming, sorryLottery winner notification (we hope)AI shipping summary at end of day
The thing you'll build next month
If you can describe it in one sentence, you can ship it on /v1/send.
Read the docs
What you get

Production-ready sms, on day one.

The boring infrastructure — signing, retries, suppressions, webhook verification, audit — is done. Your code is one POST.

  • Telnyx-routed delivery through a provisioned number
  • E.164 sender and recipient validation
  • Queued delivery with retries for transient provider failures
  • Signed delivery-status webhook processing
  • Per-recipient suppression list
  • Phone-verification gate on Free plan (anti-abuse)
  • Plan-based monthly channel limits
Compared to your alternatives

Senddio SMS vs. integrating a provider yourself

FeatureSenddioDoing it yourself
Provider account setupManaged TelnyxYours to manage
Multi-channel SDK1 SDKTwilio + SendGrid + …
Unified billingOne invoiceOne per provider
AI agent toolsClaude MCP + OpenAIBuild yourself
Spam score before sendBuilt-inBuild yourself
Your next 30 days

What changes once you ship SMS on Senddio.

01
Day 1
First OTP delivered to a real US number
02
Test
Validate payloads with a test-mode key
03
Monitor
Review signed provider delivery events
04
Maintain
Review quotas, destination support and sender compliance
RelatedA2P 10DLC— US carrier registration for business SMSOTP— One-time passwords — 2FA via SMS
FAQ

SMS — FAQ

Senddio routes production SMS through managed Telnyx infrastructure. Your workspace uses a provisioned sender number and the API validates sender and recipient numbers in E.164 format.

Senddio accepts valid sends asynchronously and returns a queued message ID. Final delivery time depends on Telnyx and the destination carrier, and delivery updates appear in your logs when the provider reports them.

Yes. Free includes 10 SMS per month. Senddio covers one managed sender number and U.S. registration charges; there is no number rental or registration bill to the customer. Sending stops at the monthly Free cap, with no overage charge. U.S. carrier registration and approval are still required before sending.

Every accepted SMS receives a Senddio message ID. Signed Telnyx delivery events update the message status in Logs, where provider failures and suppression decisions are visible.

Yes. Send the code in the body and use the optional tag field to label OTP traffic in Logs. Test-mode API keys validate the request without contacting the provider.

Other channels
Email
Transactional and broadcast email API
WhatsApp
WhatsApp Business API
Push
Push notification API
Slack
Slack messaging API
Telegram
Telegram bot messaging

Ship sms in 5 minutes.

Free forever — on the same plan as all 5 other channels, plus AI credits.

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● 300 emails/day · All 6 channels · AI credits · No card