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.

Get your agent on BlockRun Read the docs About this provider →

What it does

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.

The call

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

What it costs

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

Why per call

No seat, no minimum, no contract per vendor. Each request is quoted in dollars before it runs and settles on-chain, so an agent can pay for its own work without a human holding a credit card. How the payment works →

Related tools

Text to Speech API

LLM API

Web Search API

Questions

Can an agent place a call unattended?

Yes. The call is a paid request like any other, so an agent with a funded wallet can make one.

How is it billed?

Per call, plus a separate price for a dedicated number, both shown on this page.

Can I bring my own caller ID?

Yes — BYOT caller-ID is supported, along with fraud lookups on a number.

Which countries are covered?

US and Canada numbers today; the docs carry the current coverage.