AI tools / Voice Call API

Have an agent place a real phone call and pay for it itself

Place outbound AI voice calls and buy dedicated numbers through one endpoint, billed per call and per number in USDC. No telephony contract and no minimum.

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AI phone call API: outbound voice agents that place real calls

Place a call with a number to dial, a task describing what the agent should say and do, and optionally a voice, a language, a maximum duration and a voicemail policy. The call goes out from a number your wallet owns — buy one on the same prefix (US by default, Canada usually), renew it monthly, list and release it. Carrier and fraud lookups on any number sit alongside.

A call is priced per call regardless of length within the maximum you set; a number is a separate monthly price. The parameter table below is the call request the route validates, and each number-management endpoint is on the rate card.

How to call the voice call API — number, task, voice, duration, voicemail

One endpoint, priced in dollars before it runs and settled in USDC. No API key and no account — the request pays for itself.

POST /api/v1/voice/call
Host: blockrun.ai

Request parameters

field	type	description
to *	string	Number to dial, E.164 format.
task *	string	What the agent should say and do on the call.
from	string	A number your wallet owns. Omitted: the newest one is used.
voice	string	One of nat, josh, maya, june, paige, derek, florian, or a custom voice id.
max_duration	number	Minutes before the call is ended.
language	string	BCP-47 language tag for the conversation.
first_sentence	string	Opening line spoken before the task begins.
wait_for_greeting	boolean	Let the callee speak first.
interruption_threshold	number	How readily the agent yields when interrupted.
model	string	Conversation model tier.
voicemail_action	string	What to do when voicemail is detected.
voicemail_message	string	Message to leave when voicemail_action is leave_message.

* required

AI phone call API pricing per call and per dedicated number

endpointmethodmethodprice

/api/v1/voice/callPOST$0.541 / call /api/v1/phone/lookupPOST$0.011 / call /api/v1/phone/lookup/fraudPOST$0.051 / call /api/v1/phone/numbers/buyPOST$5.001 / number /api/v1/phone/numbers/renewPOST$5.001 / number /api/v1/phone/numbers/listPOST$0.002 / call /api/v1/phone/numbers/releasePOSTFree

Outbound calls for AI agents: from an MCP host or the SDK

In Claude Code, Claude Desktop, Cursor, Windsurf, Cline and any other MCP host, this is the blockrun_phone tool of the BlockRun MCP server — the agent calls it like any other tool and the result comes back in the conversation. In OpenClaw, Codex and Hermes, ClawRouter exposes the same catalog. In your own code, the Python and TypeScript SDKs wrap the endpoint above with types; any HTTP client works too. Every harness, with its setup →

No account and no API key stand between an agent and the first call: the request is quoted in dollars and the agent's client pays it. A team that prefers keys gets one, with a monthly invoice.

AI phone call API vs Bland, Vapi, Retell and Twilio direct

Bland, Vapi and Retell sell outbound AI calling as a platform: an account, per-minute pricing, and a console for building the agent. Twilio sells the telephony underneath — numbers and minutes — and leaves the AI to you. Each is a contract a human signs, and per-minute billing needs a balance kept topped up.

This endpoint places a call with a number to dial, a task describing what the agent should say and do, and optionally a voice, a language, a maximum duration and a voicemail policy — priced per call within the maximum you set, not per minute. The call goes out from a number your balance owns: buy one on the same prefix, renew it monthly, list and release it. Carrier and fraud lookups on any number sit alongside.

It is built on Twilio's numbers and Bland's calling, reached without either account. What it is not: an inbound call centre. Calls here are outbound, placed by a program.

Related tools

Text to Speech API

LLM API

Web Search API

AI phone call API questions: caller ID, numbers, countries, transcripts, pricing

What is an AI phone call API?

An endpoint that places a real outbound phone call and has an AI agent speak to whoever answers, following a task you write — appointment confirmations, callbacks, verifications — and returns what happened.

How is the AI phone call API priced?

Per call, within the maximum duration you set — not per minute — plus a separate monthly price for a dedicated number. Both are on the rate card above and quoted before the call is placed.

Do I need my own phone number to make AI calls?

No. Buy a dedicated number on the same endpoint — US by default, Canada usually — and the call goes out from it. Numbers renew monthly and can be listed and released.

Can I bring my own caller ID?

Yes. BYOT caller ID is supported, and carrier and fraud lookups on any number are on the same prefix.

Which countries can the AI phone call API dial?

US and Canada numbers today, with the docs carrying current coverage for outbound destinations.

Does the voice agent handle voicemail?

Yes. A voicemail policy on the request says whether the agent leaves a message you supply, hangs up on detecting voicemail, or ignores the detection; a maximum duration caps the call either way.

AI phone call API vs Bland, Vapi, Retell or Twilio direct?

Bland, Vapi and Retell are platforms with an account, a console and per-minute billing; Twilio is the telephony alone. This places a call per request, priced per call, from a number your balance owns, with no account on either.

Do I get a transcript or a result from the call?

Yes. The call returns a poll URL; polling it gives the call's status, the transcript and the recording, so a program can act on the outcome.

Can an AI agent place a phone call unattended?

Yes. The call is a paid request like any other, so an agent with a funded balance places it with no human signup, no console and no minutes to pre-buy.

Two ways to run this

Get an API key

Sign in, get a key, and call the same endpoints with usage billed to your account. For teams that want one invoice instead of one wallet.

Get an API key

Or let your agent pay per call, in USDC

No account, no API key. Three steps, and the last one is the request this page is about.

01
Point your agent at BlockRun
Install ClawRouter, or add the BlockRun MCP server to Claude Code, Cursor, Codex or OpenClaw. Any OpenAI-compatible client works too — change the base URL, nothing else.
```
curl -fsSL https://blockrun.ai/ClawRouter-update | bash
```
02
Fund a wallet with USDC
Send USDC to a wallet on Base or Solana. There is no account to create and no API key to issue: the wallet is the account, and it pays per call.
03
Call AI Phone Call API
The first call returns HTTP 402 with the exact price, your agent signs it, and the answer comes back. Payment settles on-chain; nothing is charged if the call fails.
```
POST /api/v1/voice/call
Host: blockrun.ai
```

ClawRouter setup →How paying per call works →

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