String Questions at ServiceNow: What to Expect

String manipulation is a core skill for ServiceNow developers because the platform fundamentally deals with text-based data. Workflow names, configuration item identifiers, user input in forms, API payloads, and script logic all revolve around strings. Whether you're writing a Business Rule in GlideScript (JavaScript), processing an integration, or debugging a client script, efficient string handling is non-negotiable. With 22 out of 78 total coding questions tagged for strings, ServiceNow's interview process reflects this reality. Mastering these questions demonstrates you can handle the day-to-day data transformations and validations that keep the platform running.

What to Expect — types of problems

ServiceNow's string problems tend to be practical and align with platform tasks. You won't typically see abstract, purely algorithmic string puzzles. Instead, expect problems grounded in data processing.

Common themes include:

• Validation and Parsing: Checking if a string (like an email, ticket number, or configuration item ID) matches a required format, or extracting specific substrings from a structured format (e.g., log lines, sys_ids).
• Transformation: Reformatting strings from one convention to another (e.g., camelCase to snake_case), encoding/decoding simple patterns, or building strings based on rules.
• GlideRecord-like Operations: Simulating queries or filters on string data, such as finding records where a field contains a substring or matches a pattern.
• Efficiency with Built-ins: While you need to know fundamental algorithms, ServiceNow heavily utilizes the built-in string and array methods of JavaScript (its primary scripting language). Knowing how to use .split(), .join(), .slice(), .indexOf(), and regular expressions effectively is often more important than implementing a complex algorithm from scratch.

How to Prepare — study tips with one code example

Focus on applied problem-solving rather than theory. Practice by taking common string algorithms and framing them as ServiceNow-related tasks. For example, instead of just "check if a string is a palindrome," think "validate that a configuration change number reads the same forward and backward for a specific approval workflow."

A key pattern is the two-pointer technique, essential for problems involving reversal, in-place manipulation, or checking palindromes without extra space.

def is_valid_service_tag(tag):
    """Check if a service tag is alphanumeric and a palindrome."""
    # Clean the tag: alphanumeric only, lowercased
    cleaned = ''.join(ch.lower() for ch in tag if ch.isalnum())
    # Two-pointer palindrome check
    left, right = 0, len(cleaned) - 1
    while left < right:
        if cleaned[left] != cleaned[right]:
            return False
        left += 1
        right -= 1
    return True

Recommended Practice Order

1. Master the Fundamentals: Start with basic operations—reversal, anagram checks, and palindrome detection (like the example above). Ensure you can implement these with loops and two-pointers.
2. Practice Built-in Methods: Solve problems that require efficient use of language-specific string APIs, especially JavaScript's. Practice parsing with .split() and .slice(), and pattern matching with simple regular expressions.
3. Tackle Parsing & Validation: Move to problems that mimic real data: extracting the user from an email, validating a sys_id format, or parsing a query string.
4. Simulate Platform Tasks: Finally, work on problems that combine string manipulation with other concepts, like iterating through an array of string "records" to filter or transform them based on given conditions.

This progression builds from core concepts to the applied skills you'll use on the platform.

Practice String at ServiceNow