Formatting Phone Numbers in Genesys Cloud Architect

What You Will Build

• A working Genesys Cloud Architect expression that converts an E.164 formatted phone number (e.g., +14155551234) into a standard US display format (415) 555-1234.
• This tutorial uses the Genesys Cloud Architect Expression Builder syntax and the Genesys Cloud API to validate the logic via the /api/v2/architect/expression-builder/evaluate endpoint.
• The implementation covers Python for API validation and provides the exact expression syntax required for the Architect canvas.

Prerequisites

• OAuth Client: A Genesys Cloud OAuth application with the architect:expression-builder:read scope.
• Platform: Genesys Cloud CX (formerly Pure Cloud).
• Language/Runtime: Python 3.8+ with the requests library.
• Concept: Familiarity with Genesys Cloud Architect expressions, specifically string manipulation functions like substring, concat, and replace.

Authentication Setup

Before evaluating expressions, you must obtain a valid OAuth 2.0 access token. The following Python script demonstrates the standard client credentials flow.

import requests
import json
from typing import Optional

class GenesysAuth:
    def __init__(self, client_id: str, client_secret: str, region: str = "us-east-1"):
        self.client_id = client_id
        self.client_secret = client_secret
        # Map region to the correct base URL
        self.region_map = {
            "us-east-1": "https://api.mypurecloud.com",
            "us-east-2": "https://api.us-east-2.mypurecloud.com",
            "us-west-2": "https://api.us-west-2.mypurecloud.com",
            "eu-west-1": "https://api.eu-west-1.mypurecloud.com",
            "ap-southeast-2": "https://api.ap-southeast-2.mypurecloud.com",
            "ca-central-1": "https://api.ca-central-1.mypurecloud.com"
        }
        self.base_url = self.region_map.get(region, "https://api.mypurecloud.com")
        self.access_token: Optional[str] = None
        self.expires_at: Optional[int] = None

    def get_token(self) -> str:
        """
        Retrieves an OAuth 2.0 access token using client credentials.
        Implements simple caching to avoid unnecessary requests.
        """
        import time
        if self.access_token and self.expires_at and time.time() < self.expires_at:
            return self.access_token

        url = f"{self.base_url}/oauth/token"
        headers = {
            "Content-Type": "application/x-www-form-urlencoded",
            "Authorization": f"Basic {requests.utils.quote(f'{self.client_id}:{self.client_secret}', safe='')}"
        }
        data = {
            "grant_type": "client_credentials",
            "scope": "architect:expression-builder:read"
        }

        response = requests.post(url, headers=headers, data=data)
        response.raise_for_status()

        token_data = response.json()
        self.access_token = token_data["access_token"]
        self.expires_at = time.time() + token_data["expires_in"] - 60 # Buffer 60 seconds

        return self.access_token

# Usage Example
# auth = GenesysAuth(client_id="YOUR_CLIENT_ID", client_secret="YOUR_CLIENT_SECRET")
# token = auth.get_token()

Implementation

Step 1: Understanding the Expression Logic

Genesys Cloud Architect expressions do not have a native format_phone function. You must construct the formatted string using substring extraction and concatenation.

The target format is (XXX) XXX-XXXX.
The input format is +1XXXXXXXXXX (E.164, 11 characters total).

The logic breakdown:

1. Extract Country Code: Characters 0-1 (+1). We ignore this for the final display but must account for it in indexing.
2. Extract Area Code: Characters 2-4 (3 digits).
3. Extract Prefix: Characters 5-7 (3 digits).
4. Extract Line Number: Characters 8-11 (4 digits).
5. Concatenate: Combine with parentheses, spaces, and hyphens.

The expression syntax uses 1-based indexing for the substring function in many legacy contexts, but Genesys Cloud Architect uses 0-based indexing for the substring function when used in modern expression builders. However, the syntax substring(string, start, length) is the standard.

The Core Expression:

concat(
    "(", 
    substring(phoneNumber, 2, 3), 
    ") ", 
    substring(phoneNumber, 5, 3), 
    "-", 
    substring(phoneNumber, 8, 4)
)

• phoneNumber: The variable containing the E.164 string.
• substring(phoneNumber, 2, 3): Starts at index 2 (skipping +1), takes 3 chars. Result: 415.
• substring(phoneNumber, 5, 3): Starts at index 5, takes 3 chars. Result: 555.
• substring(phoneNumber, 8, 4): Starts at index 8, takes 4 chars. Result: 1234.

Step 2: Handling Edge Cases and Validation

Phone numbers in contact centers are often messy. They may contain:

1. Non-US country codes (e.g., +44...).
2. Missing digits.
3. Existing formatting (e.g., (415) 555-1234 passed in as input).

To make this robust, we must first normalize the input to ensure it is a raw 11-digit E.164 string for US numbers, or handle the logic conditionally.

For this tutorial, we will assume the input is strictly a US E.164 number (+1XXXXXXXXXX). If the input might vary, you must wrap the formatting logic in an if statement checking the length and prefix.

Robust Expression:

if(
    and(
        equals(substring(phoneNumber, 0, 2), "+1"),
        equals(length(phoneNumber), 11)
    ),
    concat(
        "(", 
        substring(phoneNumber, 2, 3), 
        ") ", 
        substring(phoneNumber, 5, 3), 
        "-", 
        substring(phoneNumber, 8, 4)
    ),
    phoneNumber
)

This expression checks:

1. Does the string start with +1?
2. Is the total length 11 characters?
   If yes, format it. If no, return the original string to prevent breaking non-US numbers or malformed data.

Step 3: Validating via the Expression Builder API

You do not need to deploy a flow to test this. You can use the Expression Builder API to evaluate the expression in real-time. This is critical for debugging syntax errors before they hit production.

The endpoint is: POST /api/v2/architect/expression-builder/evaluate

Request Body Structure:

{
  "expression": {
    "type": "function",
    "name": "if",
    "arguments": [
      {
        "type": "function",
        "name": "and",
        "arguments": [
          {
            "type": "function",
            "name": "equals",
            "arguments": [
              {
                "type": "function",
                "name": "substring",
                "arguments": [
                  { "type": "variable", "name": "phoneNumber" },
                  { "type": "number", "value": 0 },
                  { "type": "number", "value": 2 }
                ]
              },
              { "type": "string", "value": "+1" }
            ]
          },
          {
            "type": "function",
            "name": "equals",
            "arguments": [
              {
                "type": "function",
                "name": "length",
                "arguments": [
                  { "type": "variable", "name": "phoneNumber" }
                ]
              },
              { "type": "number", "value": 11 }
            ]
          }
        ]
      },
      {
        "type": "function",
        "name": "concat",
        "arguments": [
          { "type": "string", "value": "(" },
          {
            "type": "function",
            "name": "substring",
            "arguments": [
              { "type": "variable", "name": "phoneNumber" },
              { "type": "number", "value": 2 },
              { "type": "number", "value": 3 }
            ]
          },
          { "type": "string", "value": ") " },
          {
            "type": "function",
            "name": "substring",
            "arguments": [
              { "type": "variable", "name": "phoneNumber" },
              { "type": "number", "value": 5 },
              { "type": "number", "value": 3 }
            ]
          },
          { "type": "string", "value": "-" },
          {
            "type": "function",
            "name": "substring",
            "arguments": [
              { "type": "variable", "name": "phoneNumber" },
              { "type": "number", "value": 8 },
              { "type": "number", "value": 4 }
            ]
          }
        ]
      },
      { "type": "variable", "name": "phoneNumber" }
    ]
  },
  "variables": {
    "phoneNumber": {
      "type": "string",
      "value": "+14155551234"
    }
  }
}

Note that the API requires the expression in JSON format, not the shorthand string syntax used in the UI. The shorthand substring(phoneNumber, 2, 3) translates to the nested object structure shown above.

Complete Working Example

The following Python script automates the validation of the phone number formatting expression. It constructs the JSON payload programmatically to ensure correctness, sends it to the Genesys Cloud API, and prints the result.

import requests
import json
from typing import Dict, Any

# Reusing the GenesysAuth class from Step 1
# class GenesysAuth: ... 

def build_expression_json(phone_number_value: str) -> Dict[str, Any]:
    """
    Constructs the JSON payload for the Expression Builder API.
    Implements the logic: If US E.164, format as (XXX) XXX-XXXX. Else, return original.
    """
    
    # Helper to create variable reference
    def var(name: str) -> Dict[str, Any]:
        return {"type": "variable", "name": name}

    # Helper to create string literal
    def str_lit(value: str) -> Dict[str, Any]:
        return {"type": "string", "value": value}

    # Helper to create number literal
    def num_lit(value: int) -> Dict[str, Any]:
        return {"type": "number", "value": value}

    # Helper to create function call
    def func(name: str, args: list) -> Dict[str, Any]:
        return {"type": "function", "name": name, "arguments": args}

    # Define the substring functions
    sub_country = func("substring", [var("phoneNumber"), num_lit(0), num_lit(2)])
    sub_area = func("substring", [var("phoneNumber"), num_lit(2), num_lit(3)])
    sub_prefix = func("substring", [var("phoneNumber"), num_lit(5), num_lit(3)])
    sub_line = func("substring", [var("phoneNumber"), num_lit(8), num_lit(4)])
    
    # Define the length check
    len_check = func("length", [var("phoneNumber")])

    # Define the condition: starts with +1 AND length is 11
    condition = func("and", [
        func("equals", [sub_country, str_lit("+1")]),
        func("equals", [len_check, num_lit(11)])
    ])

    # Define the true branch: Formatting
    formatted_result = func("concat", [
        str_lit("("),
        sub_area,
        str_lit(") "),
        sub_prefix,
        str_lit("-"),
        sub_line
    ])

    # Define the false branch: Return original
    original_result = var("phoneNumber")

    # Assemble the full IF expression
    full_expression = func("if", [condition, formatted_result, original_result])

    # Assemble the full payload
    payload = {
        "expression": full_expression,
        "variables": {
            "phoneNumber": {
                "type": "string",
                "value": phone_number_value
            }
        }
    }
    
    return payload

def evaluate_phone_format(auth: GenesysAuth, phone: str) -> str:
    """
    Sends the expression to Genesys Cloud and returns the evaluated result.
    """
    url = f"{auth.base_url}/api/v2/architect/expression-builder/evaluate"
    headers = {
        "Authorization": f"Bearer {auth.get_token()}",
        "Content-Type": "application/json"
    }
    
    payload = build_expression_json(phone)
    
    try:
        response = requests.post(url, headers=headers, json=payload)
        response.raise_for_status()
        
        result_data = response.json()
        
        # The API returns a 'result' object containing the 'value'
        if "result" in result_data and "value" in result_data["result"]:
            return result_data["result"]["value"]
        else:
            return "Error: Unexpected response structure"
            
    except requests.exceptions.HTTPError as e:
        print(f"HTTP Error: {e}")
        if e.response.text:
            print(f"Response Body: {e.response.text}")
        return "Failed"
    except Exception as e:
        print(f"General Error: {e}")
        return "Failed"

# Execution
if __name__ == "__main__":
    # Initialize Authentication
    # Replace with your actual credentials
    auth = GenesysAuth(
        client_id="YOUR_CLIENT_ID", 
        client_secret="YOUR_CLIENT_SECRET",
        region="us-east-1"
    )

    # Test Cases
    test_numbers = [
        "+14155551234",      # Valid US E.164
        "+442071234567",     # Non-US (should remain unchanged)
        "4155551234",        # Missing +1 (should remain unchanged)
        "+1415555123",       # Too short (should remain unchanged)
    ]

    print(f"{'Input':<15} | {'Output':<15}")
    print("-" * 35)
    
    for number in test_numbers:
        result = evaluate_phone_format(auth, number)
        print(f"{number:<15} | {result:<15}")

Common Errors & Debugging

Error: 400 Bad Request - Invalid Expression Structure

Cause: The JSON structure for the expression does not match the Genesys Cloud schema. Common mistakes include missing "type" fields or incorrect nesting of arguments.
Fix: Ensure every function call includes "type": "function" and every variable includes "type": "variable". Use the build_expression_json helper in the complete example to guarantee structural integrity.

Error: 401 Unauthorized

Cause: The OAuth token is expired or invalid.
Fix: Check the GenesysAuth class. Ensure the expires_at buffer is sufficient. If using the API directly, regenerate the token.

Error: Result is null or Original String

Cause: The input number did not meet the if condition (length != 11 or prefix != +1).
Fix: Verify the input data source. If you are testing with a number that includes spaces or dashes (e.g., +1 415-555-1234), the length will be greater than 11. You must strip non-numeric characters before formatting.

Enhanced Expression for Dirty Data:
If your input contains spaces or dashes, you must clean it first. Genesys Cloud expressions do not have a native replace for multiple characters easily, but you can chain replace functions.

// First, clean the number: remove spaces, dashes, and parentheses
let cleanedNumber = replace(replace(replace(replace(phoneNumber, " ", ""), "-", ""), "(", ""), ")", "")

// Then apply the format logic to cleanedNumber
if(
    and(
        equals(substring(cleanedNumber, 0, 2), "+1"),
        equals(length(cleanedNumber), 11)
    ),
    concat(
        "(", 
        substring(cleanedNumber, 2, 3), 
        ") ", 
        substring(cleanedNumber, 5, 3), 
        "-", 
        substring(cleanedNumber, 8, 4)
    ),
    phoneNumber
)

Note: The let syntax is not valid in the standard Expression Builder JSON API. In the JSON API, you must nest the replace calls inside the substring calls, which makes the JSON extremely deep and hard to read. For complex cleaning, consider using a Script node in Architect (JavaScript) rather than pure expressions, as JavaScript offers replaceAll and regex support.

Error: 429 Too Many Requests

Cause: Hitting the rate limit on the Expression Builder API.
Fix: Implement exponential backoff in your Python client. The requests library does not handle this automatically.

import time

def post_with_retry(url, headers, json_data, retries=3):
    for attempt in range(retries):
        try:
            response = requests.post(url, headers=headers, json=json_data)
            if response.status_code == 429:
                wait_time = 2 ** attempt
                print(f"Rate limited. Waiting {wait_time} seconds...")
                time.sleep(wait_time)
                continue
            response.raise_for_status()
            return response.json()
        except requests.exceptions.RequestException as e:
            if attempt == retries - 1:
                raise e
            time.sleep(1)
    return None

Official References

• Genesys Cloud Expression Builder API Documentation
• Architect Expression Syntax Guide
• OAuth 2.0 Authorization Guide