How to Connect Your Telnyx Account to Linxi

Telnyx or Twilio?

Both work. The differences that actually matter:

Create the account

Sign up at telnyx.com. Telnyx calls its dashboard the Mission Control Portal, at portal.telnyx.com — that is where everything below lives. New accounts start in trial mode.

Add funds — and know the $30 line

Telnyx is prepaid: numbers, messages and registrations all draw down an account balance. Two thresholds are worth knowing before you start.

10DLC operations need at least $30 on the account. Registering a brand or a campaign below that is refused outright with “Your account must have at least $30.00 to perform this operation”. It is checked per operation, not held once — so a balance that clears it today can stop clearing it three filings later.

Create a V2 API key

In the portal: Account → Keys & Credentials → API Keys, then create a key. Telnyx shows it once. It begins with KEY.

This is the whole credential — there is no second half. Telnyx API v2 authenticates with a single bearer key, which is why Linxi’s Telnyx form has one field where the Twilio form has two.

Give the key to Linxi

In Linxi: Linxi Settings → Linxi Number, choose Other, then Linxi Number via Telnyx, and paste the key. Linxi checks it against Telnyx before saving — a key Telnyx rejects is not stored, so you find out immediately rather than at your first send.

Buy a number

You can buy it from inside Linxi once the key is saved, which is the shorter path: Linxi searches Telnyx’s inventory, buys the number, creates a messaging profile and points the profile at Linxi’s inbound webhook — all in one step. Buying it in the Telnyx portal instead works too, but then steps 7 and 8 are yours to do.

A US local number costs about $1.15 a month from Telnyx, billed to your Telnyx balance, not to Linxi.

Messaging profiles — Telnyx’s version of a Messaging Service

A messaging profile owns the webhook configuration and the numbers assigned to it. It is the closest thing Telnyx has to a Twilio Messaging Service, and a number that is not attached to one looks fine at the carrier and receives nothing.

If Linxi bought the number, the profile already exists and is already attached. If you bought it in the portal: Messaging → Messaging Profiles, create one, then attach the number to it from the number’s own settings.

The inbound webhook

On the messaging profile, set:

• Webhook URL — https://linxi.app/webhook/telnyx/inbound
• Webhook API Version — 2

The API version matters. Linxi reads the v2 payload shape, and a profile left on an older version delivers something it will not understand.

Webhook signing (recommended)

Telnyx signs every webhook with Ed25519 and publishes the matching public key in the portal at Account → Keys & Credentials → Public Key. It is a 44-character base64 value ending in =.

Without it, a webhook endpoint accepts whatever is posted to it — and your number is public, printed on your Linxi Label. With it, anything not signed by Telnyx is refused.

10DLC registration

US carriers require every business number sending application-to-person traffic to be registered. It is two objects, filed in order:

• Brand — who you are. A company brand needs an EIN; a sole proprietor brand does not, and is identified by a person’s name, address and mobile number instead.
• Campaign — what you send. Use case, description, sample messages, opt-in wording, and your privacy policy and terms URLs.

Registration lives at The Campaign Registry, not at Telnyx — Telnyx files it on your behalf. That is why a brand outlives the number: releasing the number does not remove the brand.

Emergency address (E911)

If your number can place calls, register an emergency address. Telnyx charges $100 for an emergency call from an unregistered number, and the carrier — not Linxi — operates that routing.

Two things catch people out: your Telnyx account has to accept the Emergency Terms of Service in the portal first, which no API call can do for you; and Telnyx rejects ZIP+4, so use the five-digit form.

Send a test

Open a contact in Linxi and reply to them. Then text that number back from a real handset and check the message appears — sending and receiving are separate paths, and it is entirely possible for one to work while the other does not.