Twilio
Speech and voice AIIndependent review. IonBin has no partnership with Twilio and was not paid for this page. Our evaluation is our own, based on public documentation and our research. Product names are trademarks of their owners and are used for identification only. How disclosure works.
Pay-as-you-go APIs for phone numbers, calls and SMS. Conversation Relay handles speech recognition and text to speech so your app can run an AI voice agent on a real phone line. Messaging needs recipients' prior consent.
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- Putting an AI voice agent or intake flow on a real phone number
- Transactional texts to people who opted in
- Texting or autodialing people who haven't given consent
- Unregistered SMS from a 10-digit number to US recipients (A2P 10DLC registration is required)
Top use cases
- Run an AI voice agent on a phone call with Conversation Relay source ↗
- Buy a local or toll-free number and receive calls source ↗
- Send SMS to people who opted in, after A2P 10DLC registration source ↗
- Let a coding agent look up Twilio API schemas through the MCP server source ↗
In depth
Conversation Relay
Conversation Relay connects calls to your application over a WebSocket and handles speech recognition and speech synthesis. Your app supplies the conversation logic and language model. Providers and supported voices vary by configuration; the overview lists multiple speech providers rather than a universal Google-only configuration. source ↗
US voice costs
A local number costs $1.15/month and a toll-free number $2.15/month. Standard local inbound calls are $0.0085/min and standard outbound calls $0.0140/min, with destination exceptions. Conversation Relay is an additional $0.07/min; model/application costs and optional recording/storage are separate. source ↗
SMS costs
US long-code SMS starts at $0.0083 per inbound or outbound segment, not per arbitrarily long message. Carrier and registration fees are additional; a $0.001 processing fee applies to messages terminating as Failed. Destination, sender type, message length and volume affect the total. source ↗
US 10DLC registration
Application SMS/MMS from 10-digit long codes to US recipients requires A2P registration, including individual senders. Toll-free and short codes use different requirements. Verification-only use cases may use Twilio Verify instead of registering a separate 10DLC campaign. source ↗
Messaging consent
Twilio's policy requires recipient consent for the sender and subject, proof of consent and an accessible opt-out. Promotional messages require express written consent. An inbound customer message permits a relevant reply, not recurring campaigns. Carrier registration does not replace consent or jurisdiction-specific legal requirements. source ↗
MCP documentation search
The hosted public-beta MCP searches and retrieves public API specifications and docs without authentication. It does not execute account APIs, place calls or send messages. The docs name Claude, Cursor and Codex setup. Beta access is outside Twilio's standard support/SLA coverage. source ↗
Profile import
Conversation Memory supports CSV profile imports after setting up a memory store: one file at a time, up to one million rows and 100 columns, with required identifiers and traits. Empty cells overwrite existing trait values, so validate mappings with a sample first. This is a profile import, not a bulk SMS sender. source ↗
How to use it with AI
How Twilio connects to each AI platform: native connector or MCP, API through code the agent writes, browser control, or file upload.
| Platform | MCP / connector | API (agent-written code) | Browser | Upload / export |
|---|---|---|---|---|
| Claude (incl. Claude Code) | Not documented Setup steps listed for Claude. A named plugin, skill or CLI does not by itself establish an MCP/native connector pairing. Verify the route and client setup. Twilio named integration docs ↗Claude (incl. Claude Code) MCP docs ↗ | Not documented Claude (incl. Claude Code): Claude Code edits files and runs commands Twilio publishes an API, but this pairing still needs network, authentication and execution-scope checks. Twilio API ↗Claude (incl. Claude Code) docs ↗ | Inferred Claude Code with the Claude in Chrome extension (Chrome, Edge and other Chromium browsers). Twilio is a web app; the pairing itself is not documented. Claude (incl. Claude Code) browser docs ↗ | Not documented Verify which side exports and which imports, supported formats and permissions. Twilio's recorded upload/import status is yes; Claude (incl. Claude Code)'s file status is yes. These flags do not establish a file-transfer route. Twilio file docs ↗Claude (incl. Claude Code) file docs ↗ |
| OpenAI Codex | Not documented Setup steps listed for Codex. A named plugin, skill or CLI does not by itself establish an MCP/native connector pairing. Verify the route and client setup. Twilio named integration docs ↗OpenAI Codex MCP docs ↗ | Not documented OpenAI Codex: Edits files and runs commands locally; cloud tasks run in isolated workspaces Twilio publishes an API, but this pairing still needs network, authentication and execution-scope checks. Twilio API ↗OpenAI Codex docs ↗ | Inferred Only in the ChatGPT desktop app; not in the Codex CLI or IDE extension. Twilio is a web app; the pairing itself is not documented. OpenAI Codex browser docs ↗ | Not documented Verify which side exports and which imports, supported formats and permissions. Twilio's recorded upload/import status is yes; OpenAI Codex's file status is yes. These flags do not establish a file-transfer route. Twilio file docs ↗OpenAI Codex file docs ↗ |
| Google Antigravity | Not documented Twilio has an official MCP server and Google Antigravity supports MCP, but Twilio's docs don't name this pairing. Auth setup may differ. Twilio MCP docs ↗Google Antigravity MCP docs ↗ | Not documented Google Antigravity: Agents edit code and run tasks Twilio publishes an API, but this pairing still needs network, authentication and execution-scope checks. Twilio API ↗Google Antigravity docs ↗ | Inferred The /browser guide documents App and CLI support through Chrome DevTools MCP; the overview comparison conflicts on CLI availability. IDE browser features are separate. Twilio is a web app; the pairing itself is not documented. Google Antigravity browser docs ↗ | Not documented Verify which side exports and which imports, supported formats and permissions. Twilio's recorded upload/import status is yes; Google Antigravity's file status is yes. These flags do not establish a file-transfer route. Twilio file docs ↗Google Antigravity file docs ↗ |
Confirmed is reserved for evidence of the specific connection route. The current named integrations include plugins, skills and CLIs, so a named platform alone does not confirm MCP or a native connector. Inferred means each side documents a relevant capability, but no document describes the pairing. Code execution still needs network and credential access; file handling still needs a compatible format and transfer direction. Not documented means the records do not establish the route. IonBin has not tested these pairings. Recorded Oct 18, 2026.
Agent compatibility
| Level | Status | Detail / source |
|---|---|---|
| Native connector / MCP | Yes | Official docs ↗ |
| API / CLI | Yes | Official docs ↗ |
| Browser / manual | No | Browser access is recorded alongside a documented programmatic route. |
| File upload / import | Yes | Official docs ↗ |
Recorded Oct 18, 2026. Setup and plan limits vary; check the vendor's docs. How levels are assigned.
Appears in these proposed stacks
An official MCP server is documented for this tool. These platforms separately document MCP client support: ChatGPT, Claude, Cursor, Gemini (Google), Google Antigravity, Grok, Grok Bot, Lindy, LM Studio, Mistral Vibe, OpenAI Codex. This inventory does not establish compatible transport, authentication or actions for a pairing. Check the connection matrix and linked sources.
Automation hubs to assess for a custom API connection: Gumloop, Make, n8n, Zapier. Verify credentials, supported requests, limits and error handling; no configured integration is implied.
Workflows using this tool
Review
No long-form review yet. Verdict is based on research, not hands-on testing.