RexaThe short answer
Connecting Telnyx SMS lets a campaign send texts as well as place calls — a follow-up after a voicemail, a confirmation after a booking. You paste a Telnyx API key and, optionally, a messaging profile id that pins every send to one profile. Texting is bring-your-own by design: Telnyx bills you for the messages and Rexa never debits credits for a send.
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What does Rexa check when I save the credentials?
It depends on whether you pinned a profile. With `messaging_profile_id` set, Rexa fetches that profile by id and confirms it is enabled — so a disabled profile is caught at save time rather than at the first send. Without one, Rexa lists messaging profiles with a page size of one, which is enough to prove the bearer key authenticates and nothing more.
The SMS surface has its own error codes, separate from the voice ones: `invalid_api_key`, `invalid_messaging_profile`, `messaging_profile_disabled`, `rate_limited`, `network_timeout`, `unexpected_response` and `unknown_error`. Validation retries three times with one-second linear backoff, and only on the two transient codes.
How is a message actually sent?
One message per request to Telnyx’s messages endpoint. The adapter deliberately does not retry a failed send. Retry policy belongs to the delivery worker, which owns the queue, so that each individual provider attempt stays separately visible in the delivery log rather than being hidden inside a loop.
That is the opposite of the validation path, which does retry — because a validation failure is a person waiting on a form, while a send failure is a message that must not be silently duplicated.
Why is SMS separate from my voice carrier?
The SMS provider row and the telecom provider row are independent. Connecting Telnyx for voice does not connect it for SMS, and vice versa — you configure each under its own section in the dashboard, and each has its own Test connection action.
Keeping them apart means the credentials can differ in scope, and it means an SMS outage cannot take voice dispatch down with it. Telnyx is currently the only wired SMS provider.
Frequently asked questions
- Does Rexa charge me for text messages?
- No. SMS is bring-your-own by design: the platform never debits credits for a send, and Telnyx invoices you directly for the messages. Rexa’s per-minute call rate is unaffected either way.
- Do I need a messaging profile id?
- It is optional but recommended. With one set, every send is pinned to that profile and Rexa verifies the profile is enabled before saving. Without one, Telnyx routes through the default profile on the account and validation only proves the key authenticates.
- Can I send SMS through Twilio instead?
- Not today. Telnyx is the only wired SMS adapter, even though Twilio and Plivo are both supported as voice carriers. The two provider surfaces are separate, so a Twilio voice connection does not extend to messaging.
Scope, limitations, and sources
Telnyx is the only SMS provider implemented — there is no Twilio, Plivo or Vonage SMS adapter, so if you text through one of those today this will not reuse it. This surface covers outbound sending only; inbound replies are not handled here. Rexa never debits credits for a message and never proxies the bill, so message volume is entirely a matter between you and Telnyx. One more thing to plan for: Rexa captures 10DLC brand and campaign details in the dashboard, but filing them with The Campaign Registry is not yet wired, so US A2P registration remains your responsibility with your carrier.
Sources
- Telecom provider credential fields, credential validation, priority ordering and circuit-breaker behaviour. rexa.ai (accessed )
- Do-Not-Call screening, calling windows, consent handling and audit evidence. rexa.ai (accessed )
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