Telnyx

What you can build

• Check in on a lone worker by voice

  At the scheduled time the operator proposes a Dial to the worker's number, followed by gather_using_speak asking for a keypress. No answer or no digits in call.gather.ended raises the escalation you configured.

  With Lone Worker

• Send a severe-weather notice by text

  The operator drafts one SMS per site contact through POST /messages, paced to the sender's rate so nothing sits in the 4 hour queue, and records each message.finalized status.

  With Severe Weather Notice

• Attach a transcript to the call record

  With record_start on the call, call.recording.saved and call.recording.transcription.saved arrive after hangup. The operator fetches both and proposes a summary for the customer's record.

  With Call Summary

• Prove a webhook was delivered

  When an event seems missing, the operator reads GET /webhook_deliveries for the call or message, shows each attempt and response, and proposes a replay of what your endpoint never acknowledged.

  With Integration Health

Requirements

• A Telnyx account with a Mission Control Portal user who can create API v2 keys
• A Call Control Application with a webhook URL and, where used, a failover URL, and Telnyx numbers assigned to it
• A messaging profile with numbers attached; sending to US carriers off-net requires 10DLC or toll-free registration
• An HTTPS endpoint with a valid certificate that returns 200 promptly and checks the Ed25519 signature against the portal's public key

Authentication

An API v2 key created under API Keys in the Telnyx Mission Control Portal, sent as Authorization: Bearer on every request to https://api.telnyx.com/v2.

Limits

• GET /messages/{id} only returns messages up to 10 days old; older history comes from an MDR report
• A long code sends 0.1 messages per second; queued messages wait up to 4 hours, and error 40318 is returned when the queue is full
• Webhook events can arrive concurrently, duplicated, delayed, or out of order; the event id is the deduplication key
• Rate limits differ by product; a 429 carries x-ratelimit and retry-after headers, and spreading traffic across API keys is not allowed

Questions and answers

How does Telnyx sign its webhooks?

With Ed25519. Each request carries telnyx-timestamp and telnyx-signature-ed25519 headers. You fetch the public key from the Mission Control Portal, check the raw body against the signature, and reject events outside your replay window. The Telnyx server SDKs include a helper that returns the parsed event when the signature is valid.

Which webhooks follow a Dial command?

call.initiated, then call.answered or call.hangup. If answering_machine_detection was requested you also get call.machine.detection.ended, and call.machine.greeting.ended when greeting detection was asked for. A transfer adds call.bridged for Leg B; record_start adds call.recording.saved or call.recording.error after the call.

What throughput can I expect on messaging?

Per messaging profile, SMS is 50 messages per second, MMS 15, and RCS 1. Per sender, a long code is 0.1 MPS, a toll-free number 20 MPS, and a short code 1,000 MPS. US 10DLC throughput is set by the mobile operators from your registered campaign. Excess messages queue for up to 4 hours.