---
title: "Twilio"
description: "Cloud communications platform providing APIs and services for messaging, voice, email, authentication, and customer engagement."
---

# Twilio
> Cloud communications platform providing APIs and services for messaging, voice, email, authentication, and customer engagement.

## Articles

### [How to Build a Voice AI Agent with OpenAI's GPT-Live, Twilio Agent Connect, and Python](https://yomu.fyi/post/how-to-build-a-voice-ai-agent-with-openai-s-gpt-live-twilio-agent-conn.md)
- Company: [Twilio](https://yomu.fyi/company/twilio.md)
- Author: Xinghao Huang
- Published: Sep 10, 2026
- Type: Tutorial

This tutorial shows how to build a phone-based voice AI agent with OpenAI's GPT-Live, Twilio Agent Connect, and Python. It configures TAC's GPTLiveProvider to bridge Twilio Programmable Voice Media Streams to GPT-Live-1 in the OpenAI API, using 8kHz mu-law audio and avoiding custom WebSocket plumbing. The tutorial sets a proactive greeting, exposes a Python weather function through Responses delegation, and runs the function outside the real-time voice loop so a simulated three-second backend delay does not block the conversation. The resulting setup handles inbound calls through a Twilio webhook and outbound calls with an E.164 number, while the tutorial also notes per-call customization and alternative voice providers.


### [Build Voice AI Experiences with Twilio and GPT-Live-1 in the OpenAI API](https://yomu.fyi/post/build-voice-ai-experiences-with-twilio-and-gpt-live-1-in-the-openai-ap.md)
- Company: [Twilio](https://yomu.fyi/company/twilio.md)
- Author: Lenore Files
- Published: Sep 10, 2026
- Type: Announcement

The post introduces a Twilio Agent Connect integration for building production-ready voice AI experiences with OpenAI’s GPT-Live-1 speech-to-speech model. It addresses the gap between real-time speech intelligence and customer-facing communications by connecting GPT-Live-1 to Twilio Voice and Conversations while preserving context across channels and supporting reliable scale. The SDK supplies a native GPTLiveProvider that links Twilio Voice Media Streams directly to the OpenAI API without custom WebSocket plumbing, and handles turn-taking, audio streaming, interruption handling, and tool delegation. Tutorials, documentation, and example repositories cover inbound and outbound agents implemented with Python and Node.js, giving developers materials to build, test, and deploy voice applications.


### [121+ Cyber Monday email subject line examples in 2026](https://yomu.fyi/post/121-cyber-monday-email-subject-line-examples-in-2026.md)
- Company: [Twilio](https://yomu.fyi/company/twilio.md)
- Author: Jesse Sumrak
- Published: Sep 10, 2026
- Type: Tutorial

Cyber Monday email marketing depends on subject lines to help messages stand out in a crowded inbox, even when designs and discounts are strong. The guide recommends pairing subject lines with preview text, emphasizing exclusivity and urgency, stating discount amounts, using emojis selectively, and keeping copy concise. It also covers personalization, segmentation, pre-event notices, abandoned-cart messages, and reminders. More than 121 examples and templates are organized into Cyber Monday, pre-event, FOMO, abandoned-cart, and emoji-heavy categories, with additional seasonal resources. The post positions Twilio SendGrid for campaign execution and reports 75.1 billion emails processed during Cyber Week in 2025, a 14.6% increase over the previous record-breaking sending, but provides no comparative performance results for the example lines.


### [Build an AI Voice Assistant with Twilio Voice and Media Streams, OpenAI's GPT-Live API, and Node.js](https://yomu.fyi/post/build-an-ai-voice-assistant-with-twilio-voice-and-media-streams-openai.md)
- Company: [Twilio](https://yomu.fyi/company/twilio.md)
- Author: Paul Kamp
- Published: Sep 10, 2026
- Type: Tutorial

This tutorial shows how to build an AI voice assistant that answers phone calls using Twilio Programmable Voice, Twilio Media Streams, OpenAI's GPT-Live-1, and Node.js. GPT-Live-1 acts as the speech-to-speech model for listening, talking, and handling interruptions, while the delegated gpt-5.6-terra model handles deeper reasoning and tool use. The implementation uses a Fastify server with WebSocket support, dotenv configuration, a marin voice, and separate prompts for the voice and backend roles. Callers can request a city's top headline through the custom get\_top\_headline function or ask factual questions through OpenAI's hosted web\_search tool. The guide exposes port 5050 with ngrok, points a Twilio number at an /incoming-call webhook, and concludes that the working example fits in under 200 lines.


### [Make Outbound Calls with Twilio Voice and Media Streams, GPT-Live-1 in the OpenAI API, and Node.js](https://yomu.fyi/post/make-outbound-calls-with-twilio-voice-and-media-streams-gpt-live-1-in.md)
- Company: [Twilio](https://yomu.fyi/company/twilio.md)
- Author: Paul Kamp
- Published: Sep 10, 2026
- Type: Tutorial

This tutorial shows how to build an outbound AI voice agent that uses Twilio Programmable Voice and Media Streams to call a permitted phone number, rather than waiting for inbound calls. It connects the call to GPT-Live-1 in the OpenAI API through a Node.js server, with Fastify, ws, dotenv, and the Twilio helper library handling the application and relay. The implementation reads the destination from a --call flag, validates E.164 formatting, exposes the server through a public tunnel, and uses environment variables for credentials and the calling number. Owlie identifies itself as an AI assistant, retrieves a callback note with get\_callback\_reason, delegates factual questions to hosted web\_search, and can be interrupted during speech. The completed demo rings the chosen number, explains why it is calling, and can return random callback notes or web-searched answers, while the tutorial stresses verified numbers, model access, and outbound-calling compliance.


### [10+ best practices to improve your email deliverability](https://yomu.fyi/post/10-best-practices-to-improve-your-email-deliverability.md)
- Company: [Twilio](https://yomu.fyi/company/twilio.md)
- Author: Jesse Sumrak
- Published: Sep 9, 2026
- Type: Tutorial

Email deliverability determines whether messages reach inboxes rather than merely being accepted by recipient mail servers, and the guide distinguishes delivery rate from inbox placement. It recommends authenticating domains with SPF and DKIM, using appropriate IP allocation and warm-up, applying double opt-in, writing genuine subject lines, offering preference controls, cleaning lists, avoiding purchased addresses and spam traps, sending valuable content, and monitoring metrics. The stated benchmark for good deliverability is at least 95%, while the excerpt cites Twilio SendGrid's 99% API rate and warns that changing providers does not repair domain or IP reputation. Case studies report Shopify at 99.5% overall delivered and 91.3% inbox placement, and Klaviyo at 99.94% average delivery, with the latter also reporting 1.9-second median delivery speed.


### [From AI Agent to Human Agent: ElevenLabs Call Handoffs with Twilio](https://yomu.fyi/post/from-ai-agent-to-human-agent-elevenlabs-call-handoffs-with-twilio.md)
- Company: [Twilio](https://yomu.fyi/company/twilio.md)
- Author: Ricardo Bangueses
- Published: Sep 9, 2026
- Type: Tutorial

This reference integration connects an ElevenLabs voice agent to Twilio Programmable Voice, enabling escalation from automated support to a human when a conversation becomes complex, sensitive, or unresolved. Twilio retains ownership of the original inbound call while ElevenLabs conducts the real-time conversation; an escalate\_to\_human webhook tells Twilio to update that parent Call SID with new TwiML. In the Flex example, Enqueue sends the caller into a TaskRouter workflow, creating a voice task with intent and summary context, while the Call SID and metadata such as direction and phone numbers travel into ElevenLabs as dynamic variables for the handoff. The blueprint describes Studio-owned routing, direct TaskRouter or Flex routing, and custom TwiML destinations; Conversation Memory and Conversation Intelligence are optional additions, and the implementation is explicitly a proof of concept rather than a production drop-in.


### [Integrate Deepgram Flux with Twilio's Conversation Relay](https://yomu.fyi/post/integrate-deepgram-flux-with-twilio-s-conversation-relay.md)
- Company: [Twilio](https://yomu.fyi/company/twilio.md)
- Author: Dhruv Patel
- Published: Sep 8, 2026
- Type: Tutorial

Twilio's ConversationRelay connects phone calls to an AI stack while handling speech-to-text, text-to-speech, and the WebSocket session, leaving application code focused on the LLM and conversation logic. This tutorial updates a Node.js ConversationRelay application to use Deepgram Flux, which combines transcription and turn detection and is described as reducing response latency by up to 200–600 milliseconds and false interruptions by around 30 percent. It walks through cloning a Fastify demo, exposing it with ngrok, configuring environment variables, and adding Flux settings to the ConversationRelay TwiML, including eotThreshold, speechTimeout, and ignoreBackchannel. The supplied configuration uses an end-of-turn threshold of 0.8, a 3,000-millisecond speech timeout, and enabled backchannel ignoring, while the tutorial also explains partial prompts, smart formatting, and recognition hints.


### [Holiday email marketing best practices for 2026 (and beyond)](https://yomu.fyi/post/holiday-email-marketing-best-practices-for-2026-and-beyond.md)
- Company: [Twilio](https://yomu.fyi/company/twilio.md)
- Author: Jesse Sumrak
- Published: Sep 8, 2026
- Type: Tutorial

Holiday email marketing carries higher volume and stakes during the seasonal shopping period, making planning, deliverability, personalization, and post-holiday retention central concerns. The guide recommends warming sending volume before Black Friday and Cyber Monday, increasing it by only 25–40% at a time to avoid sudden mailbox-provider signals. It also calls for a calendar with one or two lower-volume days each week, list hygiene, segmentation, testing, and journey-driven campaigns that account for shipping and fulfillment constraints. For holiday-season signups, the post-holiday process uses sign-up date or source cohorts, monitors open and click rates, and can reduce frequency, run re-engagement campaigns, or suppress addresses after 30–60 days without engagement. Examples and templates emphasize concise, value-driven content, specific offers, and personalization such as location or past purchases.


### [Choosing a low-latency infrastructure layer for conversational AI](https://yomu.fyi/post/choosing-a-low-latency-infrastructure-layer-for-conversational-ai.md)
- Company: [Twilio](https://yomu.fyi/company/twilio.md)
- Author: Luke Morgan
- Published: Sep 8, 2026
- Type: Problem & solution

Conversational AI call-center latency can feel like dead air, and the delay may come less from LLM inference than from the infrastructure moving audio among telephony, media servers, ASR, the agent, and TTS. The described approach uses a unified voice path: ConversationRelay provides a WebSocket API to stream live call audio, handle speech-to-text and text-to-speech in one connected pipeline, connect with a backend agent, and support barge-in. It is model-agnostic, allowing teams to retain their LLM, knowledge bases, AI tools, and third-party voice providers, while Conversation Orchestrator, Conversation Memory, and Agent Connect address context and integration. Twilio’s internal benchmarks report median latency below 0.5 second and below 0.725 second at the 95th percentile, though relevance and context also matter alongside speed.


### [What is bring your own LLM (BYO LLM)?](https://yomu.fyi/post/what-is-bring-your-own-llm-byo-llm.md)
- Company: [Twilio](https://yomu.fyi/company/twilio.md)
- Author: Jesse Sumrak
- Published: Sep 4, 2026
- Type: Explainer

Bring your own LLM (BYO LLM) is an architecture in which teams choose the model powering their AI agents while a platform supplies communication infrastructure. The division leaves model selection, prompts, reasoning logic, tool definitions, and called systems with the team, while channels, conversation context, audio streaming, identity resolution, and human escalation remain with the platform. The post explains why bundled models create quality, migration, compliance, and cost-control constraints, including the inability to route simple interactions to smaller models and complex work to frontier models. It describes adding a third-party model to an existing contact center through middleware, a shared message handler, tools and knowledge, channel registration, and context-preserving handoff. Twilio Agent Connect is presented as a self-hosted Python and TypeScript SDK under the MIT License, with voice streaming and integrations for existing contact-center workflows.


### [Build a Video Chat App with ASP.NET Core and Angular using Twilio Video](https://yomu.fyi/post/build-a-video-chat-app-with-asp-net-core-and-angular-using-twilio-vide.md)
- Company: [Twilio](https://yomu.fyi/company/twilio.md)
- Author: Donal Toomey
- Published: Sep 3, 2026
- Type: Tutorial

This tutorial builds a small group video chat application with an ASP.NET Core Web API and Angular single-page app using Twilio Programmable Video. The API binds typed Twilio credentials, mints short-lived access tokens locally with the API Secret, reads active rooms through the Twilio REST API, and pushes room-list changes over SignalR instead of browser polling. The Angular client uses the twilio-video library to capture camera and microphone media, connect to rooms, render participants, and provide device selectors. Local development runs the API alongside ng serve, while a Release MSBuild target runs npm ci and npm run build so dotnet publish places the SPA in the API's wwwroot. The resulting local test demonstrates a two-participant call and a live active-room count that updates when someone joins or leaves.


### [4 must-ask questions before you delegate to your AI agent](https://yomu.fyi/post/4-must-ask-questions-before-you-delegate-to-your-ai-agent.md)
- Company: [Twilio](https://yomu.fyi/company/twilio.md)
- Author: Jesse Sumrak
- Published: Sep 3, 2026
- Type: Problem & solution

Automation roadmaps that prioritize ticket volume and low complexity can improve containment while lowering customer satisfaction when customers did not want a task automated. The post proposes four screening questions: how reversible a mistake is, whether the task touches money, health, or identity, whether the customer needs a transaction or to be heard, and whether the AI can access the necessary context. It cites a Twilio survey of 7,652 consumers, including 80% comfortable with appointment or reservation scheduling and 60% unwilling to have AI handle a medical inquiry. Tasks that fail the test can be split between AI and people: AI gathers information, verifies identity, retrieves history, and drafts a recommendation before a human decides, with Twilio Conversation Orchestrator handing conversation history and profile to Twilio Flex. The recommendation is to start with tasks where errors are relatively cheap and the data is available.


### [How to disclose AI to customers without killing the conversation](https://yomu.fyi/post/how-to-disclose-ai-to-customers-without-killing-the-conversation.md)
- Company: [Twilio](https://yomu.fyi/company/twilio.md)
- Author: Jesse Sumrak
- Published: Sep 1, 2026
- Type: Tutorial

Customer service teams may avoid disclosing AI because they fear customers will leave, but the post argues that unclear or delayed disclosure creates more frustration than honesty. It recommends a short first-turn greeting that says “AI,” explains what the agent can do, and offers an immediate route to a human, with renewed disclosure when a conversation moves to SMS or voice. Web chat, SMS, and voice examples show how to pair disclosure with an exit, while voice should disclose before the caller explains the issue and leave a pause. The post identifies burying the disclosure, using ambiguous labels, apologizing, over-explaining, and omitting escalation as failure modes. It proposes checking Twilio Conversation Intelligence transcripts alongside containment and escalation rates to assess wording changes, citing research on customer expectations and bypass behavior.


### [When AI takes the wheel: The rise of invisible identity intelligence in 2026](https://yomu.fyi/post/when-ai-takes-the-wheel-the-rise-of-invisible-identity-intelligence-in.md)
- Company: [Twilio](https://yomu.fyi/company/twilio.md)
- Author: Catie Kolander
- Published: Sep 1, 2026
- Type: Explainer

Point-in-time authentication treats an initial password, MFA, or passkey check as sufficient trust for the rest of a session, leaving post-login account takeovers, session hijacking, and risky API actions insufficiently evaluated. The proposed model replaces this front-door assumption with continuous context evaluation using passive telemetry such as network, telecommunications, device, behavioral, and transaction signals, then intervenes when risk scores or policy thresholds rise. For AI agents, delegated authority sets temporal, monetary, and API limits through short-lived credentials, while Know Your Agent lineage links execution to the authorizing human and deploying enterprise. High-impact actions can trigger human checkpoints through SMS, push, or voice channels, while immutable logs, transparent scoring, tenant isolation, and session lineage support auditability and compliance. The resulting architecture aims to keep low-risk autonomous work unobtrusive while making sensitive operations controllable and provable.


### [Complete guide to sending email to Google: Rules, signals & setup](https://yomu.fyi/post/complete-guide-to-sending-email-to-google-rules-signals-setup.md)
- Company: [Twilio](https://yomu.fyi/company/twilio.md)
- Author: Tony Williams
- Published: Sep 1, 2026
- Type: Tutorial

Sending email to Google requires understanding differences between consumer Gmail and Google Workspace, plus the authentication and reputation signals used by Google’s filtering systems. The guide says SPF and DKIM are required for all senders, while DMARC is required for senders exceeding 5,000 messages per day to Google inboxes; it also gives a bounce example for missing alignment. It recommends keeping user-reported spam below 0.1%, never reaching 0.3%, and providing one-click unsubscribe handling. Google Postmaster Tools reports compliance, spam rate, authentication success, and delivery errors, while the Feedback-ID header enables aggregate complaint analysis by campaign or sender ID. Workspace administrators can apply additional filters, so successful delivery to Gmail does not guarantee placement in a corporate Workspace inbox.


### [How to Approve Real Users and Block Fake Accounts at Sign Up with Lookup and Verify in PHP](https://yomu.fyi/post/how-to-approve-real-users-and-block-fake-accounts-at-sign-up-with-look-php.md)
- Company: [Twilio](https://yomu.fyi/company/twilio.md)
- Author: Kelley Robinson, Matthew Setter
- Published: Aug 31, 2026
- Type: Tutorial

The tutorial shows how to combine Twilio Lookup and Verify in a PHP sign-up flow that screens phone numbers before sending an OTP. It starts with Line Type Intelligence to accept mobile numbers, optionally checks reachability with Line Status, and uses Identity Match to compare submitted first and last names against authoritative sources without revealing underlying data. If those checks pass, the application sends a six-digit verification code and validates it through a Verify service. The provided implementation uses PHP 8.5, Slim, Twig, Monolog, and the Twilio REST client, with environment flags controlling optional checks and logs recorded in data/app.log. Testing covers mobile, toll-free, VoIP, and name-mismatch cases, while the pricing discussion recommends ordering cheaper checks before more expensive Identity Match and Verify calls.


### [Your customers don't hate AI — they hate you lying about it](https://yomu.fyi/post/your-customers-don-t-hate-ai-they-hate-you-lying-about-it.md)
- Company: [Twilio](https://yomu.fyi/company/twilio.md)
- Author: Jesse Sumrak
- Published: Aug 31, 2026
- Type: Explainer

Twilio research reports a major gap between brands’ and consumers’ accounts of AI-agent disclosure: 81% of brands say agents identify themselves immediately, while only 22% of consumers report that experience. Teams may treat a system-prompt line, widget label, or one-time channel message as disclosure, even though customers can miss it or encounter a different experience on SMS or voice. Recommended practice includes naming “AI agent” at the first turn, repeating disclosure across channels, explaining accessible data and decision logic, and offering an immediate route to a person. It also recommends checking transcripts rather than trusting configuration, using conversation analysis to verify whether disclosure fired. Research cited says 76% expect identification at the start, 49% want data-access transparency, and 54% trust AI more when its logic is explained.


### [How to Confirm Phone Number Ownership with Lookup Identity Match](https://yomu.fyi/post/how-to-confirm-phone-number-ownership-with-lookup-identity-match.md)
- Company: [Twilio](https://yomu.fyi/company/twilio.md)
- Author: Kelley Robinson
- Published: Aug 31, 2026
- Type: Tutorial

The tutorial shows how to use Twilio Lookup Identity Match to confirm that a person is linked to a submitted phone number and reduce sign-up fraud. It describes a zero-knowledge match against authoritative sources such as mobile carrier records, with possible use during sign-up, login, account changes, or checkout. The implementation starts from an international telephone input project, collects first and last names alongside an E.164 phone number, and passes them to the Lookup API with the identity\_match field; the response exposes per-field statuses and a summary score. The sample JavaScript treats the check as successful when the phone is valid and both names are exact or high partial matches, then displays the result, while the post also notes approval requirements outside the US, test parameters, and alternative Lookup packages.


### [Build a Video API with Twilio Programmable Video, Node.js, TypeScript, and Express](https://yomu.fyi/post/build-a-video-api-with-twilio-programmable-video-node-js-typescript-an.md)
- Company: [Twilio](https://yomu.fyi/company/twilio.md)
- Author: Mia Adjei
- Published: Aug 31, 2026
- Type: Tutorial

This tutorial builds an Express API for creating and managing Twilio Programmable Video rooms with Node.js and TypeScript. It sets up a project with Express, TypeScript 5, ts-node, node-dev, dotenv, and the Twilio Node.js helper library, while requiring Node.js 20 or 22 LTS. Twilio account credentials are stored in environment variables loaded from .env, which is excluded through .gitignore. The TypeScript configuration compiles strict CommonJS source from src into build and targets ES5; routes call the Rooms API to create rooms and complete them by changing status to completed, disconnecting connected participants. The result is a server-side room-management foundation, with access-token issuance identified as the next step for browser or mobile participants.


[Newer posts](https://yomu.fyi/company/twilio/page/3.md) · [Older posts](https://yomu.fyi/company/twilio/page/5.md)