Telnyx API
Browse all Telnyx APIsOfficial vendor OpenAPI document · agent-readyCommunicationsVoice Telephonybearer713 EndpointsREST
For Agents
Send SMS/MMS, control voice calls, manage phone numbers, and run AI assistants on calls through a single API with 713 endpoints covering telephony, messaging, and AI inference.
Use for: I need to send an SMS message through Telnyx, I want to initiate a voice call and play a greeting, Search for available phone numbers in a specific area code, Start an AI assistant on an active call for transcription
Not supported: Does not handle email delivery, push notifications, or notification orchestration - use for telephony, SMS, fax, SIP, and embedded AI only.
Deliver SMS, MMS, voice calls, fax, SIP trunking, and AI-powered call control through a unified API with 713 endpoints. Purchase and manage phone numbers across 60+ countries, configure messaging profiles and campaigns for 10DLC compliance, and run AI assistants on live calls. Includes embedded AI features for chat completions, embeddings, transcription, and fine-tuning alongside core telephony services.
Install Jentic One Beta
Connect the Telnyx API to your agent
Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the Telnyx API, or any other public or private API you need. You set the rules, the agent never sees your credentials, and every call is logged.
Two steps, two machines. Install the instance in a safe environment, then register your agent from wherever it runs.
1
Step 1: Jentic One Host machine
# On the machine that will host your Jentic One instance:
curl -fsSL "https://jentic.com/install.sh?src=apis&api=%2Fapis%2Ftelnyx.com%2Ftelnyx-api" | sh2
Step 2: Agent machine
# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL "https://jentic.com/install.sh?src=apis&api=%2Fapis%2Ftelnyx.com%2Ftelnyx-api" | sh
jentic register # connects your agent to your Jentic One instanceJentic One is in public beta. The setup above keeps your agent separate from the instance, which is what you want before using real credentials: an agent running as the same OS user as Jentic One can read its stored keys directly. Just evaluating? A single local install is fine to start. See the secure deployment guide for the tiers.
Capabilities
What an agent can do with Telnyx API.
Send SMS, MMS, and group messages through long codes, short codes, and number pools with delivery tracking
Control active voice calls with answer, hangup, transfer, gather DTMF, record, and text-to-speech commands
Purchase and configure phone numbers across 60+ countries with instant activation
Run AI assistants on live calls for conversational IVR, transcription, and intelligent call routing
Send and receive faxes programmatically with status tracking and media retrieval
Configure SIP trunking with credential and IP-based authentication for enterprise voice
Generate text embeddings, run chat completions, and fine-tune models through integrated AI endpoints
Use Cases
Patterns agents use Telnyx API for, with concrete tasks.
★ AI Agent Communications Automation
AI agents send messages and control calls through Jentic by searching for Telnyx operations, loading schemas, and executing with bearer token injection. Jentic handles authentication from your Jentic One instance so agents operate across SMS, voice, and AI endpoints without managing API keys. A single API surface covers messaging, call control, number management, and AI inference.
Send an SMS from +15551234567 to +15559876543 with text 'Your appointment is confirmed' via POST /messages and verify the message_id is returned
Programmable Voice with AI Assistants
Build intelligent call flows by combining Telnyx call control commands with embedded AI assistants. Start a call, then attach an AI assistant for real-time transcription, conversational IVR, or AI-powered information gathering. The assistant handles natural language interaction while the call control API manages hold, transfer, and recording - all through a single platform without external AI service integrations.
Initiate a call via POST /calls, then start an AI assistant on the call via POST /calls/{call_control_id}/actions/ai_assistant_start with a greeting prompt
10DLC Messaging Compliance
Register brands and campaigns for US 10DLC messaging compliance through the API. Create messaging profiles that associate phone numbers with registered campaigns, ensuring messages are delivered with carrier trust scores. The API handles brand registration, campaign submission, and number assignment - covering the full compliance lifecycle without manual carrier portals.
Create a messaging profile via the API, register a brand, submit a campaign for approval, and assign a phone number to the messaging profile
Multi-Channel Number Management
Search, purchase, and configure phone numbers for voice, SMS, MMS, and fax across 60+ countries. Filter available numbers by area code, features, and number type. Configure purchased numbers with connection assignments, messaging profiles, and emergency addresses. Supports number porting, block purchases, and sub-organization number allocation.
Search available US phone numbers with SMS capability via GET /available_phone_numbers with filter[features]=sms and purchase the first result
Key Endpoints
713 endpoints — deliver sms, mms, voice calls, fax, sip trunking, and ai-powered call control through a unified api with 713 endpoints.
METHOD
PATH
DESCRIPTION
POST
/messages
Send an SMS or MMS message
GET
/messages/{id}
Retrieve message details and delivery status
POST
/calls
Initiate an outbound voice call
POST
/calls/{call_control_id}/actions/answer
Answer an incoming call
POST
/calls/{call_control_id}/actions/ai_assistant_start
Start an AI assistant on an active call
GET
/available_phone_numbers
Search available phone numbers for purchase
POST
/faxes
Send a fax
POST
/ai/chat/completions
Run AI chat completions
POST
/messages
Send an SMS or MMS message
GET
/messages/{id}
Retrieve message details and delivery status
POST
/calls
Initiate an outbound voice call
POST
/calls/{call_control_id}/actions/answer
Answer an incoming call
POST
/calls/{call_control_id}/actions/ai_assistant_start
Start an AI assistant on an active call
GET
/available_phone_numbers
Search available phone numbers for purchase
POST
/faxes
Send a fax
POST
/ai/chat/completions
Run AI chat completions
Why Jentic?
What agents get from Jentic-routed access to this vendor.
Setup
Wiring the Telnyx API by hand means setting up its bearer token, attaching it to every call against api.telnyx.com/v2, and writing the call-control, messaging, and retry glue across hundreds of endpoints yourself. Through Jentic you install once, import the Telnyx API from the API Directory, store the token once, and your agent calls it.
Permission scoping
The Telnyx API puts the call control id in the URL path (/calls/{call_control_id}/actions/answer), so a rule can pin your agent to one call: it can answer that call or start its AI assistant and nothing else. You choose the operations it may call, so ones like sending messages or ordering phone numbers are not included unless you add them.
Credential isolation
Your Telnyx token is stored once, encrypted, by your own Jentic One instance and injected at execution time. It never enters the agent's prompt, logs, or context.
Intent-based discovery
Agents search Jentic by intent such as 'send an SMS' or 'answer an inbound call', and Jentic returns the matching Telnyx API operation with its input schema so the agent calls the right endpoint without browsing the reference docs.
Related APIs
Alternatives and complements available in the Jentic catalogue.
FAQs
Specific to using Telnyx API through Jentic.
What authentication does the Telnyx API use?
The Telnyx API uses Bearer token authentication. Include your API key in the Authorization header as 'Bearer YOUR_API_KEY'. Through Jentic, your Telnyx bearer token is stored encrypted in your Jentic One instance and injected automatically into requests, so agents never handle the raw API key.
Can I run AI assistants on live voice calls with Telnyx?
Yes. After initiating or answering a call, POST to /calls/{call_control_id}/actions/ai_assistant_start with a system prompt and configuration. The AI assistant handles conversational interaction on the call in real-time. Stop it with /actions/ai_assistant_stop when complete.
What are the rate limits for the Telnyx messaging API?
Telnyx messaging rate limits depend on your number type and messaging profile. Long codes support 1 message per second per number. Toll-free numbers support higher throughput after verification. Short codes support 30+ messages per second. The API returns 429 when limits are exceeded.
How do I send an SMS through Jentic with the Telnyx API?
Search for 'send an SMS message' in Jentic to find the Telnyx messages endpoint. Load the operation schema, then execute with from (your Telnyx number), to (recipient), and text (message body). Install with pip install jentic and use the search-load-execute flow. Jentic injects the bearer token automatically. Get started with Jentic One, the self-hosted execution layer.
Does Telnyx support 10DLC messaging compliance?
Yes. Telnyx provides API endpoints for brand registration, campaign submission, and number-to-campaign assignment. Create a messaging profile, register your brand, submit a campaign for carrier approval, and assign numbers to the profile. The API covers the full 10DLC compliance lifecycle.
Can I send faxes through the Telnyx API?
Yes. POST to /faxes with the to number, from number, and media URL of the document to fax. The API returns a fax ID for status tracking. Retrieve fax status and received faxes via GET /faxes/{id}. Supports PDF and TIFF formats.
Can I limit what my agent is allowed to do with the Telnyx API?
Yes. Because you run Jentic One yourself, your own rules decide which Telnyx operations and credentials your agent may use, so you can allow only what a task needs. Since the Telnyx API puts the call control id in the URL path, such as /calls/{call_control_id}/actions/answer, a rule can pin the agent to a single call so it can answer that call or start its AI assistant and nothing else. Operations like sending messages via POST /messages or ordering phone numbers stay out of reach unless you explicitly add them.
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