REST APIs in ServiceNow provide a powerful way to interact with the platform programmatically, enabling integration with external systems and applications. REST (Representational State Transfer) is an architectural style that uses standard HTTP methods to perform operations on resources.
ServiceNo…REST APIs in ServiceNow provide a powerful way to interact with the platform programmatically, enabling integration with external systems and applications. REST (Representational State Transfer) is an architectural style that uses standard HTTP methods to perform operations on resources.
ServiceNow offers two main types of REST APIs:
1. **Inbound REST APIs**: These allow external systems to communicate with ServiceNow. The platform provides several out-of-box APIs including the Table API, Aggregate API, Import Set API, and Attachment API. The Table API is most commonly used, allowing CRUD (Create, Read, Update, Delete) operations on ServiceNow tables using HTTP methods: GET (retrieve), POST (create), PUT/PATCH (update), and DELETE (remove).
2. **Outbound REST APIs**: These enable ServiceNow to call external web services. You can configure REST Messages in ServiceNow to define endpoints, authentication, and HTTP methods for communicating with third-party systems.
**Key Components**:
- **Endpoints**: URLs that identify specific resources (e.g., /api/now/table/incident)
- **HTTP Methods**: Define the action to perform
- **Headers**: Contain metadata like Content-Type and authentication tokens
- **Request/Response Body**: Data exchanged, typically in JSON or XML format
**Authentication Methods**:
ServiceNow supports Basic Authentication, OAuth 2.0, and API keys to secure REST communications.
**Scripted REST APIs**:
For custom requirements, administrators can create Scripted REST APIs, defining custom endpoints and logic using server-side JavaScript.
**Best Practices**:
- Use appropriate authentication mechanisms
- Implement proper error handling
- Apply access controls through ACLs
- Monitor API usage through transaction logs
- Use pagination for large data sets
REST APIs are essential for ServiceNow administrators and developers as they facilitate seamless data exchange between ServiceNow and other enterprise systems, supporting automation and workflow integration across the organization.
REST APIs in ServiceNow
Why REST APIs Are Important in ServiceNow
REST APIs are fundamental to modern ServiceNow development because they enable seamless integration between ServiceNow and external systems. In today's connected enterprise environment, organizations rarely use ServiceNow in isolation. REST APIs allow data to flow between ServiceNow and other applications such as HR systems, financial software, monitoring tools, and custom applications. Understanding REST APIs is essential for any ServiceNow developer or administrator who needs to build integrations or expose ServiceNow data to other systems.
What Are REST APIs?
REST (Representational State Transfer) is an architectural style for designing networked applications. REST APIs use HTTP methods to perform operations on resources identified by URLs. In ServiceNow, there are two main types of REST functionality:
Inbound REST APIs: These allow external systems to interact with ServiceNow. ServiceNow provides both the Table API (for standard table operations) and Scripted REST APIs (for custom endpoints).
Outbound REST: This allows ServiceNow to call external REST services using REST Messages and the RESTMessageV2 API.
How REST APIs Work in ServiceNow
HTTP Methods: - GET - Retrieves data from ServiceNow - POST - Creates new records - PUT - Updates existing records (replaces entire record) - PATCH - Partially updates records - DELETE - Removes records
Table API: The Table API is a built-in REST API that provides CRUD operations on any ServiceNow table. The endpoint format is: /api/now/table/{tableName}
Scripted REST APIs: These allow developers to create custom REST endpoints with specific logic. They are defined in the Scripted REST APIs module and consist of: - API definition (namespace, name, version) - Resources (individual endpoints) - Scripts that process requests and return responses
REST Messages: For outbound integrations, REST Messages define the connection to external systems including: - Endpoint URL - Authentication method - HTTP methods available - Request headers and parameters
- Request Headers: Include Content-Type (usually application/json) and Accept headers - Response Codes: 200 (Success), 201 (Created), 400 (Bad Request), 401 (Unauthorized), 404 (Not Found) - sysparm parameters: Used with Table API to filter, limit, and format responses (sysparm_query, sysparm_limit, sysparm_fields) - Access Control: REST API access is governed by ACLs and user roles
Exam Tips: Answering Questions on REST APIs in ServiceNow
1. Know the difference between Table API and Scripted REST API: Table API is built-in and works with any table; Scripted REST APIs are custom-built for specific use cases.
2. Memorize HTTP methods and their purposes: Questions often ask which method to use for specific operations. Remember GET retrieves, POST creates, PUT/PATCH updates, DELETE removes.
3. Understand REST Message components: Know that REST Messages are used for outbound calls and contain endpoint definitions, HTTP methods, and authentication settings.
4. Focus on sysparm parameters: The exam may test your knowledge of query parameters like sysparm_query for filtering and sysparm_display_value for returning display values.
5. Remember authentication options: Be familiar with Basic Auth and OAuth 2.0 as common authentication methods for REST integrations.
6. Pay attention to response formats: ServiceNow REST APIs typically return JSON by default. Know how to specify the desired format using Accept headers.
7. Access control matters: Questions may address who can access REST APIs based on roles and ACLs. Remember that proper permissions are required even for API access.
8. Practice with real scenarios: Many exam questions present integration scenarios. Think about whether the question describes inbound (external to ServiceNow) or outbound (ServiceNow to external) communication.