Fire an AI phone call from a single request
Trigger a real phone call straight from your app, CRM or automation. One request dials one number or a whole list, an AI agent holds the conversation, and you get the transcript, summary and outcome back. Built on Nixflex, on your own carrier, at $0.08 a minute.
POST /v1/calls/outboundbatchCalls your product makes, not a person
Inbound gets most of the attention — everyone wants to stop missing calls. Outbound is where a lot of businesses recover revenue they already paid to acquire: the lead follow-ups, the reminders, the callbacks a team never has time to make. An AI calling API turns each of those into a single line of code. You name the number and the agent; the platform dials, talks, and hands you back structured data.
Because the call is triggered from your own systems, it fits wherever your logic already lives — fire it from your backend when a form comes in, from your CRM when a stage changes, or from an automation in Zapier or Make.
One call, or thousands
Send one request to /v1/calls/outbound with a number and an agent. The call fires right away — perfect for a speed-to-lead callback the moment a form is submitted.
Hand over a whole list and the platform works through it — reminders, follow-ups and surveys at volume, each call using the same agent and returning its own result.
What developers wire it into
Confirm or reschedule the day before, and cut no-shows without a person on the phone.
Call a new lead within a minute of the form landing, while intent is highest.
A polite, consistent nudge that leaves the right voicemail when no one picks up.
Ask a few structured questions after a visit and get the answers back as data.
Capture the basics up front and pass only serious buyers to a human.
Read a code aloud for anyone who cannot receive a text, confirmed by webhook.
Every call comes back as data
A call is only useful if you can act on it. Each outbound call returns a record with the full transcript, a summary, a sentiment score, and any fields you asked the agent to extract — available from GET /v1/calls or pushed to your webhook the instant the call ends. And the agent does more than talk: it books on your calendar, sends a text, transfers to a person, or calls your API mid-conversation and uses the result to keep going.
Why build outbound on Nixflex
Trigger a call with a single HTTP request — single or batch — from anywhere your code runs.
Transcript, summary, sentiment and extracted data on every call, by pull or webhook.
The agent detects machines and leaves the message when your prompt says to — or hangs up.
Premium model included; you pay only for the seconds each call actually lasts.
Bring your own Twilio or Telnyx number and keep call and number costs on your bill.
Books, texts, transfers, and calls your own APIs during the conversation.
Comparing calling APIs? Nixflex is a modern alternative to Retell, Vapi and Bland. Compare them →
Frequently asked questions
What is an AI calling API?
An AI calling API lets you start a phone call from your own code. You send a request naming the number to call and the agent to use, and the platform dials, holds a real conversation, and returns what happened. Instead of a person making the call, an AI agent does — and instead of a dashboard, you trigger it from your app, CRM or automation.
How do I trigger a call?
Send a request to POST /v1/calls/outbound with the number to call and the agent that should handle it. The call fires immediately. To reach a whole list, send it as a batch campaign rather than one request per number — useful for reminders, follow-ups and surveys at volume.
What can I use outbound AI calls for?
The common ones are appointment reminders and confirmations, lead follow-up and speed-to-lead callbacks, payment reminders, surveys and feedback, and read-aloud verification codes. Anything where a short, structured conversation needs to happen at scale and a human does not have the time.
What happens when the call hits voicemail?
The agent detects the machine and, if your prompt tells it to, leaves the right message — otherwise it hangs up. You are billed only for the seconds the call actually lasted, so an unanswered dial costs pennies rather than a full conversation.
How do I get the results of each call?
Every call returns a record with the full transcript, a summary, a sentiment score and any structured data you asked the agent to extract. Pull it with GET /v1/calls, or receive a webhook the moment each call ends so the outcome lands straight in your systems.
Can the agent do things during an outbound call?
Yes. It can book, reschedule or cancel appointments on your calendar, send a text mid-call or after, transfer to a human, and call your own API through a custom function to look something up — then use the answer to continue the conversation.
What does the AI calling API cost?
A flat $0.08 per minute of voice, pay-as-you-go, with the premium model included. You bring your own Twilio or Telnyx number, so carrier and number charges stay on your account, and there is no monthly platform fee to start.
Make your first AI call from code
Grab an API key and trigger an outbound call in a single request.