AI Voice Agent Webhooks and API: Push Call Events Anywhere

Your AI voice agent hangs up. Two seconds later, the outcome, a short summary, and a link to the recording should already be sitting in your own systems. That is the job of AI voice agent webhooks: they push every call event to a web address you control the instant it happens. Topcalls also ships a full REST API, so your software can start calls, manage leads, and check your balance on demand. Getting call data out in real time is the difference between acting on a call and reading about it tomorrow.

Key Takeaways

• Topcalls webhooks fire on seven call events, from every hang-up to a booked appointment or a conversion, pushing data to your server in real time.
• Every completed call sends its outcome, a 2-3 sentence AI summary, the duration in seconds, a timestamp, and a signed recording link valid for 90 days.
• The Topcalls REST API can start an outbound call, pause a campaign, check your balance, and bulk-import up to 2,000 leads in one request.
• Webhooks and the API cost nothing extra. They are included in the flat $0.35 per minute, with no per-seat fee and no integration add-on.
• Topcalls webhooks push every call event to your systems in real time, so the outcome, summary, and recording link land seconds after the agent hangs up.
• Most teams never write a webhook. The no-code integration builder connects call events to hundreds of apps with no code and no server to run.

What are AI voice agent webhooks?

AI voice agent webhooks are automated messages your calling platform sends to a web address you own the moment a call event happens. Rather than your app repeatedly asking Topcalls "any new calls yet?", Topcalls pushes the data to you. Each webhook is a small HTTP POST carrying the call outcome and details. Your server catches it and runs whatever you built next.

The difference is push versus poll. Polling wastes requests and adds delay; a webhook arrives within seconds of the hang-up. Topcalls processes 63,000+ AI calls a day, and every one of them can trigger a webhook. If you'd rather not run a server at all, the no-code integration builder covers the same events, and the complete guide to AI voice agent integrations walks through all four connection methods.

What call events can fire a webhook?

Topcalls exposes seven call-event triggers. The one most teams start with is when a call ends, which fires after every call, including failures and voicemails. The rest map to moments a sales team cares about: a booked appointment, a requested callback, a scheduled follow-up, a voicemail, a failed call, and a conversion. Any of the seven can carry call data to your endpoint.

• When a call ends: fires after every single call, including no-answers and voicemails. The catch-all most workflows listen to.
• When an appointment is booked: the agent scheduled a meeting. Route it straight to your calendar and CRM.
• When a callback is requested: the prospect asked to be called back. Queue the next attempt automatically.
• When a follow-up is scheduled: the agent set a future touchpoint. Feed it into your outreach sequence.
• When a call hits voicemail: no live contact. Trigger an SMS or an email instead.
• When a call fails: no answer, busy, or rejected. Log it and decide whether to retry.
• When a conversion happens: the outcome you defined as a win. Fire your revenue tracking.

These are the same triggers that power no-code post-call workflows and feed use cases like AI lead qualification. With a webhook, you decide exactly what your own code does with each one.

What's in a call webhook payload?

A Topcalls call webhook carries the full result of the call. Every completed call includes the outcome or disposition, a 2-3 sentence AI summary of what was said, the call duration in seconds, a timestamp, and a signed link to the recording that stays valid for 90 days. If the AI collected data during the call, a confirmed email or a budget range for example, that is in the payload too.

Treat the shape above as a guide, not a contract. What matters is what arrives: enough to update a CRM record, score a lead, or start a follow-up without ever opening the dashboard. The real-time analytics dashboard shows the same data on-screen if you'd rather read it than pipe it.

What can you do with the Topcalls REST API?

The Topcalls REST API flips the direction. Instead of Topcalls pushing to you, your software calls Topcalls to make things happen. You can start an outbound call from your own app, pull recent call records, add or remove phone numbers, start or pause a campaign, check your account balance and minutes, and run full lead-list management, including a bulk import of up to 2,000 leads in one request.

• Start and control calls: kick off an outbound call, cancel one that's queued, or stop a call that's already live.
• Manage leads at scale: create a list, add, update, or delete a lead, and bulk-import up to 2,000 leads at once.
• Run campaigns: start or pause a smart campaign programmatically, no dashboard clicks.
• Pull call records: list recent calls and read their outcomes and summaries into your own reporting.
• Check the meter: read your account balance and remaining minutes before you launch a batch.

Teams already syncing a CRM usually pair the API with an existing pipeline. The AI dialer CRM integration guide shows how call data lands in Salesforce, HubSpot, or Pipedrive, and the API is how you wire that into a custom system instead.

Want to see what faster call data is worth to your pipeline? Run the numbers in the ROI calculator before you write a line of code.

Webhooks, the builder, or the API: which to use?

Pick by direction and by who sets it up. The no-code integration builder connects call events to hundreds of ready apps, and anyone can build it in-app. Webhooks push those same events into your own database or app and need a developer. The REST API runs the other way, letting your code start calls and manage data. Most teams need only the builder.

The three are not mutually exclusive. A common setup uses the integration builder for the easy 80% and a webhook or the API for the custom last mile.

How do you secure and test a webhook?

Verify the signature on every webhook before you trust it. A signed payload carries a hash computed from a shared secret, so your server can confirm the message really came from Topcalls and wasn't altered in transit. This is the same approach Stripe documents for its own webhooks. Reject anything that fails the check, and never act on an unsigned request.

• Check the signature: compute the hash with your secret and compare. A mismatch means the request isn't from Topcalls.
• Return fast, then work: reply with a 200 quickly and do the heavy lifting after. Retry-on-failure is built into every step, so a slow reply can cause duplicate deliveries.
• Test with a throwaway endpoint: point the webhook at a tool like RequestBin or webhook.site first, read a real payload, then build against its actual shape.

The encryption and compliance that protect calls on Topcalls secure infrastructure apply to the data a webhook carries too. It stays TCPA, GDPR, and DNC compliant end to end.

Where are webhooks the wrong tool?

Webhooks are the wrong tool for most teams. If all you need is to post a Slack message, add a HubSpot contact, or log a row in Google Sheets, the no-code builder does that in minutes with no server to run and nothing to maintain. MuleSoft's 2026 Connectivity Benchmark Report found the average organization runs 957 applications and only 27% are connected. A builder closes most of that gap without code.

Reach for a webhook or the API only when you own software no connector touches: a proprietary database, an internal tool, a bespoke billing flow. For everything else, start with post-call automations or the full integrations guide, and drop to code only where you have to.

How do you get started?

Getting started with Topcalls is a strategy call, not a signup form. Tell the team which systems you run and how deep you need the integration to go, and they'll map webhooks, the API, and the builder to your stack. Every path bills at the same flat $0.35 per minute. Book a strategy call on the contact page, or size the upside first with the ROI calculator.