AI voice agent webhooks and API: syncing calls to your CRM

AI voice agent API and webhooks let your own systems react to what happens on calls: when a call ends, you receive an event with the outcome, and you write it into your CRM, notify a closer or trigger a follow-up. Webhooks push events to you; the API lets you pull data and act on demand.

This article is for the person who has to wire it up: a developer, an operations lead or a technical founder. It explains the moving parts and the patterns that keep a CRM sync reliable. For exact field names and endpoints, check the documentation in the dashboard, since this overview is deliberately about design rather than payload specifics.

What Purple Voice exposes

The Developers area of the dashboard holds three things:

• Webhooks: URLs you register so the platform can notify you of events.
• API keys: credentials that let your code call the API.
• Automations: rules that react to events without you writing a server.

On plans, webhooks, API access, insights and advanced automations are part of Pro. Smaller plans cover booking and summaries within the dashboard, and email and calendar integrations, but not custom webhooks. See the pricing page for the full list.

Webhooks versus the API

People mix these up, but they solve different problems.

	Webhook	API request
Direction	Platform calls you	You call the platform
Trigger	An event happens	Your code decides
Best for	Real-time updates, CRM logging	Backfills, reports, on-demand lookups
Failure mode	You miss an event if you are down	You can always retry

Use webhooks for the live flow and the API to reconcile, so a missed event never means lost data.

The events worth listening to

You rarely need every event. The ones that earn their keep for a sales workflow:

• Call completed: the core event. It carries who was called, how it ended, and links or fields for the summary and transcript.
• Appointment booked: so sales or operations can prepare, and your CRM shows the meeting.
• Transfer requested or completed: so a human knows a hot lead was handed over.
• Call not reached or failed: to feed retry reporting or trigger another channel.

If you are logging into a CRM, the call completed event alone often does 80 percent of the job. For what a useful logged summary looks like, see AI call summaries and CRM notes.

A reliable CRM sync pattern

Here is a pattern that survives real traffic.

1. Receive the webhook over HTTPS and respond with a success status quickly. Do not do heavy work in the request handler.
2. Verify the request. Use the secret or signature mechanism described in the documentation to confirm it came from the platform.
3. Queue the work. Put the payload on a queue or job table so slow CRM calls cannot block delivery.
4. Deduplicate. Store an event or call identifier and ignore repeats. Webhooks are usually delivered at least once, which means sometimes more than once.
5. Match the contact. Look up the CRM record by a stable key: your own contact ID if you passed one in, otherwise a normalised phone number.
6. Write the update. Create a note or activity, set the status, and attach the summary.
7. Log failures and keep a way to replay them.

A tiny sketch of the handler's shape, in pseudocode:

on POST /hooks/purple-voice:
    verify signature or secret
    if already_processed(event.id): return 200
    enqueue(event)
    return 200

worker:
    contact = crm.find_by_phone(normalise(event.contact.phone))
    crm.add_note(contact, event.summary)
    crm.set_status(contact, map_outcome(event.outcome))
    mark_processed(event.id)

Idempotency, ordering and retries

Three problems appear the first week.

• Duplicates. The same event can arrive twice. Store processed IDs so a repeat does nothing.
• Order. Events can arrive out of sequence. Do not assume "booked" arrives after "completed". Use timestamps from the payload rather than your server's arrival time.
• Downtime. If your endpoint is unavailable, you may miss events. Check the current documentation for delivery and retry behaviour, and build a nightly reconciliation job that uses the API to compare recent calls with what your CRM holds.

Phone numbers are the usual join key

Matching is where syncs go wrong. Store numbers in one format, such as E.164 with the country code, on both sides. A lead recorded as 07700 900123 in your CRM and +44 7700 900123 in your call data will not match until you normalise both. If you control the upload, add your own contact ID to the campaign list so you can match on it instead. See how to launch an AI calling campaign for list preparation.

Security basics

Call data contains personal information, and sometimes recordings. Treat the integration accordingly.

• Use HTTPS only. No plain HTTP endpoints.
• Verify the source of every request before trusting it.
• Keep API keys in a secrets store, never in front-end code or a public repository, and rotate them if they leak.
• Limit what the receiving system can do. A handler that only adds notes cannot delete records.
• Keep transcripts and recordings only as long as you have a reason, and follow the rules that apply to you. GDPR and call recording covers retention and notices at a general level.

No server? Use automations

If you do not want to host a handler, the Automations feature in the Developers area is designed for rules that react to events directly. They are a good fit for simple jobs, like notifying a channel when a call books or flags a transfer. Move to your own webhook handler when you need transformations, deduplication or writes to a system the automations do not reach.

Testing the integration

1. Register a webhook pointing at a test endpoint, or a request inspector, before the real one.
2. Make a test call to your own phone, as described in test your AI voice agent.
3. Check the payload that arrives and compare each field with the call in the dashboard.
4. Replay the same event to confirm your handler ignores the duplicate.
5. Stop your endpoint, make another call, and confirm your reconciliation job picks it up afterwards.

What to log in the CRM

Do not dump the whole transcript into a text field. Log the outcome, the summary, the next step and a link to the call. Keep the full transcript one click away. Reps read short notes and ignore long ones.

Try it

If you are on the Free plan, you can explore the dashboard, run test calls and see summaries with no card. Webhooks, the API and advanced automations are included on Pro. Start at voice.purplerocket.co, and compare plans on the pricing page.