Connecting Your Software to Your Phone System with the Cannon VoIP API

Most businesses run their phone system in one place and everything else, their CRM, helpdesk, scheduling tool, custom internal software, somewhere else. That gap means someone's manually dialing numbers, copying call notes into a CRM by hand, or hunting through a portal for a call log that should've just shown up automatically. Cannon VoIP's API closes that gap: it lets your other software talk directly to your phone system, so calls, texts, faxes, and call data flow between them without anyone lifting a finger.

What an API integration actually does

An API (application programming interface) is simply a defined way for two pieces of software to exchange information. In practical terms for your phone system, that means your CRM or internal tools can ask Cannon VoIP to do something, like place a call or send a fax, and Cannon VoIP can tell your software when something happens, like a call coming in or ending. No manual re-entry, no switching between apps mid-task.

What you can build with it

What this looks like in practice

A few real-world patterns customers ask about most:

• CRM screen pop: when a call comes in, your CRM automatically opens the matching contact record so your team never has to ask "who am I talking to?"
• Automatic call logging: the call record feed posts every finished call to your own system, so it can be logged against the right customer or deal record without anyone typing notes into two systems. HubSpot, Zoho and GoHighLevel get finished calls logged automatically with no code at all.
• Appointment reminders: your scheduling software triggers an outbound call or text reminder automatically ahead of a booked appointment.
• HIPAA fax workflows: a medical office's records system sends patient documents by fax automatically and confirms delivery, without staff ever touching a fax machine.
• Custom reporting: pull raw call data into your own dashboards or BI tool instead of relying only on what a portal shows you.
• Directory sync: new hires added in Microsoft 365 or Google Workspace show up as phone system contacts automatically, no double data entry.
• Missed-call follow-up: a missed-call webhook opens a task or ticket in your own system so someone calls back the same day.

For your developer or IT team

At a technical level, integration happens two ways: your software makes requests to trigger actions (place a call, send a text or fax, look up a record, update a schedule), and Cannon VoIP sends event notifications (webhooks) to your software the moment something happens. API keys use the same API as the portal, so most of what you can do in the portal can be automated. The exceptions are deliberate: a key can never manage users, sign port papers or touch billing, and it never outranks the person who created it. If your developer has built an integration against any modern communications platform before, the concepts, API keys, webhooks, call events, will be familiar. We work directly with your team (or your software vendor) to scope exactly which pieces you need and get credentials set up.

Webhooks cover:

• Calls, missed calls, texts, voicemails and faxes
• Meetings, recordings, tickets, new contacts, form submissions and port-outs
• A call record feed that posts every finished call to your own system
• Every delivery signed with HMAC SHA-256 and a timestamp, so your endpoint can verify it came from Cannon VoIP
• Failed deliveries retry with backoff, and a receiver that was down gets the missed events later
• Send a test event, and see recent deliveries with their status and errors

Running your own on-site phone system? Connect it with a SIP trunk:

• Authenticate by registration or by source IP address, including ranges, and see whether a registration trunk is currently registered
• Calls in and out, including calls to other companies on our network
• A ring time and a failover destination for when your system does not answer
• A default caller ID, with international calling blocked unless you allow it
• Record outbound calls from the trunk, and cap concurrent calls to stop a runaway system
• Text and picture messaging over the trunk with its own API key, with opt-out rules applied

Prefer an AI assistant to code? You can connect Claude, Gemini, ChatGPT or any Model Context Protocol assistant to your account, choose which areas it can reach, and decide how far it acts alone. High-risk actions wait for a person to approve them, and every assistant action is logged under the assistant's name.

MSPs and IT teams wire these events into ticketing and dashboards: see our MSP page. For the vocabulary behind calls and events, the glossary covers every term.