Introduction to Call Flow Builder
SignalWire's Call Flow Builder is a no-code visual tool for call process creation and management. It features a simple drag-and-drop interface for creating complex call flows with multiple branches and decision points.
All elements of the call flow are represented as nodes in a tree structure. You can easily add, remove, and rearrange elements in the call flow using the visual interface.
Add or remove any element from the call flow by dragging it into the desired location, and define links between them using the connection lines.
Extend each flow by integrating external APIs, or by using SignalWire Markup Language (SWML). Call Flow Builder also offers built-in versioning to streamline testing multiple configurations.
Under the hood, Call Flow Builder generates valid SWML (SignalWire Markup Language), meaning all the power of SWML is available whenever you need more control over your call flows.
Getting Started
To get started with the Call Flow Builder, you can head to the Call Flow Builder section in your SignalWire Dashboard.
Check out this brief demo to see how to add, configure, and connect nodes in Call Flow Builder.
Creating a New Call Flow
To create a new call flow, click on the Add New button in the Call Flow Builder section of the Dashboard.
From here, you can give your call flow a name, and then click Save to create the new call flow.
After creating the call flow, the Call Flow will show up in the list of call flows in the Dashboard.
Building a Call Flow
Once a Call Flow has been created, you can click on the More Options button to open the Call Flow Builder interface.
From here, click on the Edit option to open the Call Flow Builder page.
Adding Nodes
When you first open a new Call Flow, you will see a canvas with a single node: the Handle Call node. This node is the entry point for incoming calls and serves as the start of all Call Flows. From here the Call Flow Builder interface allows you to create and manage call flow nodes using a visual drag-and-drop interface.
Every node has a single input connector on the left, and one or more output connectors on the right. These connectors allow you to connect nodes together to create flows and logical relationships.
Add nodes to the Call Flow by dragging them from the left-hand panel and dropping them onto the canvas. Starting with the Handle Call node, you can connect a node by clicking and dragging from the output connector (right side of node) to the input connector (left side of node) of another node. You will see an arrow connecting the two nodes, indicating that they are connected.
Configuring Nodes
Some nodes have configuration options that can be set by clicking on the node. This will open a configuration panel where you can set the options for that node. For example, the Play Audio or TTS node allows you to select an audio file or enter text to be played to the caller.
Deleting Nodes
To delete a node, you can click on the delete icon located on the right side of the node.
Additionally, you can delete a node if they have configuration options open by clicking the Delete node button in the configuration panel.
Versioning Call Flows
Call Flow Builder offers built-in versioning to which enables the user to create multiple versions of a call flow. The benefit of versioning is that it allows you to test different configurations of a call flow without affecting the live version, or to revert to a previous version if needed.
Once a call flow has been created, you can click on the Version History button located in the top left corner of the Call Flow Builder interface.
This will open a panel showing all the versions of the call flow, along with a timestamp of when the version was created.
Deploying a new version
If you wish to make edits to a call flow, you can create a new version making any changes you need.
Once you are satisfied with the new version, you can click the Deploy button to make the new version the live version of the call flow.
When a new version is saved, it will add a new entry to the version history. The name of the
version will be +1 from the previous version. E.g. Version 1.0, Version 2.0, Version 3.0, etc.
Reverting to a previous version
If you need to revert to a previous version of a call flow, you can open the version history panel
by clicking the Version History button and selecting the version you wish to revert to.
Once you have the desired version selected, a Restore button appear that will allow you to revert back to that version.
Nodes
A call flow consists of a series of nodes, which represent different actions that can be taken during a call. Each node has a specific purpose, and you can connect nodes together to create a flow that guides the caller through the call process.
Starting Node
Starting nodes are the first nodes in a call flow and are used to handle incoming calls.
| Node Type | Description |
|---|---|
| Handle Call | Handles an incoming call. Starting point in the Call Flow |
Action Nodes
Action nodes perform specific actions during a Call Flow, such as playing audio, answering/hanging up a call, or sending an SMS.
| Node Type | Description |
|---|---|
| Answer Call | Answers an incoming call. |
| Hang Up Call | Hangs up the call. |
| Play Audio or TTS | Plays an audio file or text-to-speech message to the caller. |
| Send SMS | Sends an SMS message to the caller. |
Forward Nodes
Forward nodes transfer the call to another number.
| Node Type | Description |
|---|---|
| Forward to Phone | Forwards the call to a phone number. |
Record Nodes
Record nodes record the caller's/callee's voice/voicemail.
| Node Type | Description |
|---|---|
| Start Call Recording | Starts recording the call. |
| Stop Call Recording | Stops recording the call. |
| Voicemail Recording | Records a voicemail. |
Input Nodes
Input nodes collect input or http requests from the caller.
| Node Type | Description |
|---|---|
| AI Agent | Connects the call to an AI agent. |
| Gather Input | Collects input from the caller. |
| Request | Sends an HTTP request. |
Decision Nodes
Decision nodes make decisions based on the conditions specified.
| Node Type | Description |
|---|---|
| Conditions | Evaluates conditions and branches the call flow accordingly. |
| Execute SWML | Executes SWML code. |
| Set Variables | Switches variables based on conditions. |
| Unset Variables | Unsets a variable. |
Using Variables
Variables allow you to create a dynamic Call Flow that responds to user input and other outside information.
While the Set Variables node allows you to manually create your own variables at any time,
you can also use variables from Request nodes or even get variables from the inbound call.
All variables must be in the following format to signal to the Call Flow Builder that it should process a variable: %{<variable>}.
Inbound Call Variables
The following variables exist for all inbound calls. At this time, the direction is always inbound, but the other values are very useful and can be referenced throughout the whole Flow.
| Variable Name | Description |
|---|---|
%{call.from} | The phone number of the caller. |
%{call.to} | The phone number the call was made to. |
%{call.direction} | The direction of the call. |
%{call.call_id} | The unique identifier for the call. |
%{call.state} | The state of the call. |
%{call.type} | The type of call. |
Variable Example
Request Variables
Variables that you get from a Request node can be accessed using %{request_response.<object_field>}.
For example, if we send a GET request to timeapi.io, the response we’ll receive will look like this:
{
"year": 2023,
"month": 7,
"day": 27,
"hour": 16,
"minute": 9,
"seconds": 9,
"milliSeconds": 640,
"dateTime": "2023-07-27T16:09:09.640945",
"date": "07/27/2023",
"time": "16:09",
"timeZone": "America/Chicago",
"dayOfWeek": "Thursday",
"dstActive": true
}
To reference the “hour”, “date” and “dayOfWeek” from this response as variables in the Call Flow, we would format the variables like this:
%{request_response.hour}
%{request_response.date}
%{request_response.dayOfWeek}
Please note that response values that are strings will need special formatting to be used with conditional expressions or JavaScript operators.
Use the format %{vars.request_response.<object_field>'} to use the value of the string.
In the example above, the response parameter "dayOfWeek" has a string value of "Thursday". The following condition will only be met when the day of the week is Thursday:
%{vars.request_response.dayOfWeek == 'Thursday'}
You can also use slice() to remove everything from the string after the third character to give you a shortened day of the week (Fri, Sat, Mon):
Key: short_day
Value: %{vars.request_response.dayOfWeek.slice(0,3)}
Variables with JavaScript Operators
You can use variables along with standard Javascript operators. This can be useful if you need to alter a variable or pass a condition that matches an expression.
For example, you can use the slice() method
to remove everything from the %{call.from} variable except for the area code of an inbound caller.
Within a Set Variables node, you can set the following:
Key: area_code
Value: %{call.from.slice(2,5)}
You can even combine this with a Conditions node as in the example below. Condition 1 uses the OR operator to check if the area code is 321 or 407.
If either of those is true, the call is forwarded to +15552223333. A second condition in the same node checks for a 419 area code and forwards the call to +15553334444.
Condition 1: %{area_code}==321||%{area_code}==407
Condition 2: %{area_code}==419
slice() method to alter a variable.