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The IVR toolkit is CallFactory’s developer-focused action library for building custom call flows. Every action—Answer, Play, Dial, Record and StartStream—gives you precise control over what happens during a call, so your logic isn’t limited by a dashboard interface.
You use the toolkit to build selection menus, gather caller input, stream audio to AI services, connect callers with agents, and handle every edge case cleanly. The toolkit runs on the same IVR platform that powers all standard CallFactory features, which means you get the same building blocks our own product teams use.
- Structured actions with clear signatures and examples
- Stream audio to AI, STT or your own endpoint
- Build complete call flows without extra hardware
- Full documentation and developer support
Benefits of the IVR toolkit
See how the IVR toolkit helps development teams build professional call flows that align precisely with their backend systems and processes.
Complete control over call logic
You decide what happens at every step of a call, because you play prompts, gather input, route on conditions, stream to AI and handle errors with predictable, well-documented actions.
Built for developers
Every action has a clear signature, typed return values, error handling and working code examples, so you build with confidence using structured actions that fit naturally into your backend.
AI-ready audio streaming
You stream live call audio to any WebSocket endpoint—for example an AI assistant, a speech-to-text engine or your own analytics service—with StartStream and StopStream giving you full control over when and where audio flows.
Runs on proven infrastructure
The toolkit runs on CallFactory's own IVR platform, the same infrastructure that powers all our phone features, so you don't need extra hardware or third-party dependencies and everything works with your existing CallFactory numbers.
How the IVR toolkit works
The IVR toolkit is a library of actions that your own code calls during a live call. When a call arrives your application receives it, then step by step you decide what happens with the help of these actions.
A typical flow starts with Answer(), then plays a welcome message with Play(), gathers input via PromptDigit() or GatherDigits() and routes the caller with Dial() and Connect(). Every action returns a typed result, so your code always knows what happened and can handle every possible answer cleanly.
Audio streaming for AI and speech-to-text
With the StartStream and StopStream actions you stream live call audio in real time to any WebSocket endpoint. This way you connect a call to an AI assistant, a speech-to-text engine or your own analytics service without needing to buffer the audio first or route it indirectly.
You decide when the stream starts, which direction the audio flows (from caller to AI, from agent to AI or both at once) and when it stops. The stream runs in parallel with your other IVR actions, so you can play prompts, gather input or transfer while the AI listens in the background.
Who uses the IVR toolkit
The toolkit is designed for development teams who need complete control over call behaviour. Think of SaaS platforms that add voice features to their product, contact centres that build their own routing logic and companies that want to integrate telephony with their CRM, ERP or internal tools.
If you have a development team writing backend code, the IVR toolkit gives you everything you need to build professional call flows, from simple menus to complex AI-driven conversations. Documentation, code examples and developer support are included, so your team becomes productive quickly without having to discover integration patterns through trial and error.
The relationship between toolkit and platform features
Every CallFactory feature, such as the selection menu, the call queue system, smart voicemail and the voicebot, is built from the same IVR actions documented in this toolkit. The toolkit gives you direct access to those same building blocks, so you work at the same level as our own product teams.
That means everything CallFactory does by default your development team can do too, and often more besides. You combine standard features with your own logic, add integrations that don’t exist as standard features and build call flows that align entirely with how your own business works.
Getting started
Contact us to discuss your requirements, then we’ll give your team access to the toolkit documentation, working code examples and a development environment. If you need help designing your first call flow our team advises on architecture and shares best practices we’ve seen work for similar deployments.
For businesses needing full capacity and isolation, dedicated IVR servers is the natural next step, where your custom call flows run in an environment reserved entirely for you.
Learn more about other features
Find more information about our features that can improve your business communication.
Voicebot
AI-powered voice assistants built on our IVR platform. Automate incoming calls with natural conversation, data lookups, and smart routing.
Dedicated IVR servers
Your own IVR server with complete control. Build custom telephony applications, connect AI platforms, and scale from 4 to 200+ channels. The natural upgrade from our private API when you need more.
API integrations
Tell us what you need, we build the endpoints. Our private API lets you integrate CallFactory telephony into your own software — no generic library, no guesswork, no wasted development time.
IVR toolkit — frequently asked questions
Get clear answers to questions about the IVR toolkit and how it works for your business in practice.
Yes. The toolkit is a library of actions your own backend calls, which means your development team writes each call flow in code. If you don’t have developers in-house, our ready-made custom telephony and voicebot options are often a more logical starting point.
You programme in any common language, because your code runs in a virtual machine we host for you. The documentation, actions and examples use C# (.NET) as the primary language, but you’re not locked to C# if your team prefers a different language.
Yes. The StartStream action opens a real-time WebSocket connection to any endpoint you choose, whether that’s an AI assistant, a speech-to-text engine or your own service. You decide the audio direction and can stop the stream at any time.
Yes. All IVR actions work with your existing CallFactory numbers and routing, so you don’t need to make changes to your phone setup.
Yes. The toolkit uses the same building blocks as all CallFactory features, so you can continue using standard features like selection menus and call queues alongside your own logic.
Every action supports cancellation tokens, so the token is cancelled as soon as the caller hangs up and your code gets a clear signal to stop. No loose connections or unhandled states remain.
Yes. Our team advises on architecture, reviews your flow design and helps with more complex integrations. For fully managed solutions our custom telephony and voicebot services are a logical next step.
The toolkit is available to CallFactory customers, and depending on the complexity of your implementation and hosting requirements extra costs may apply. We always discuss pricing before work begins.
