REST API Basics for Cisco Devices – Automate Smarter, Not Harder [CCNP Enterprise]

If you’ve ever felt overwhelmed jumping between CLI screens or manually configuring the same changes across dozens of Cisco devices—then it’s time we talk automation. Today, we’re diving into the REST API basics for Cisco devices, a game-changer for anyone looking to modernize their workflow.

In this post, I’ll simplify REST APIs for you with easy language, practical examples, and a small working lab in EVE-NG. Whether you’re preparing for Cisco DevNet or just tired of repetitive configs, you’ll walk away knowing how to query, configure, and manage Cisco routers or switches through APIs—like a modern-day NetOps ninja. Let’s go!

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Theory in Brief – What is REST API?

REST (Representational State Transfer) is an architectural style for designing networked applications. It uses HTTP methods (GET, POST, PUT, DELETE) to perform operations on resources, which are often represented in JSON or XML format.

When applied to Cisco devices, REST APIs allow us to programmatically interact with routers, switches, firewalls, or even controllers—without touching the CLI. Instead of SSH or Telnet, you can now fetch interface status, configure routing, or monitor traffic with a simple HTTP request.

Why REST API Matters in Networking

Modern network engineers need to manage thousands of devices at scale. REST APIs enable:

• Automation of routine tasks
• Real-time monitoring
• Easy integration with external systems like Ansible, Python, Grafana
• Improved agility and consistency

The best part? Cisco platforms like IOS-XE, NX-OS, and DNA Center already support REST APIs out-of-the-box.

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Key REST API Concepts in Networking

Concept	Description
Endpoint	URL where a device exposes data (e.g., /interfaces or /routing)
HTTP Methods	GET (read), POST (create), PUT (update), DELETE (remove)
Headers	Metadata like Content-Type, Authorization (token/username)
Body	Payload sent to or received from API (usually JSON)
Authentication	Basic Auth or Token-based
Status Codes	200 (OK), 201 (Created), 404 (Not Found), 401 (Unauthorized), etc.

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Comparision – REST vs CLI vs NETCONF

Feature	REST API	Traditional CLI	NETCONF
Format	JSON/XML	Text	XML
Interface	HTTP(S)	SSH	SSH
Use Case	Automation, Monitoring	Manual config	Structured config mgmt
Vendor Support	Broad (Cisco, Juniper, etc.)	Universal	Limited
Security	HTTPS + Auth	SSH login	SSH login
Pros	Scalable, Simple, Programmatic	Direct access, Widely known	Schema-based, Reliable
Cons	Requires coding	Time-consuming	Complex setup

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Pros and Cons of REST APIs in Cisco

Pros	Cons
Easier integration with tools (Postman, Python, Ansible)	Requires basic scripting knowledge
Fast and scalable configuration changes	Not available on all legacy devices
Vendor-neutral standard	Limited transaction capabilities compared to NETCONF
JSON is lightweight and human-readable	APIs must be enabled and secured carefully

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Essential CLI Commands (Cisco REST API)

Purpose	Command	Description
Enable REST API	restconf	Enable RESTCONF on IOS-XE
Enable HTTP/HTTPS	ip http secure-server	Enables secure API access
Verify API server status	show platform software restconf statistics	Check REST API performance
Debug REST calls	debug restconf all	Monitor API interactions
View API access logs	`show logging	include restconf`
Generate auth credentials	username admin privilege 15 secret admin123	Basic Auth setup
Check interface config via API	Use GET on /restconf/data/ietf-interfaces:interfaces	Verify interface list in JSON

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Real-World Use Case: Automating Interface Monitoring

Scenario	Details
Environment	Enterprise with 150+ branch routers
Requirement	Automatically monitor interface status every 5 mins
Manual Effort	Previously required login to each router via SSH
Solution	Python script using REST API to GET interface data from each device
Benefit	Saved 20+ hours/week, immediate alerting enabled via monitoring tools

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Small EVE-NG LAB – REST API with Cisco IOS-XE

Lab Objective

• Enable REST API on Cisco IOS-XE router
• Use Postman or curl to perform GET/POST requests
• Simulate real-world automation

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Lab Topology Diagram

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Step-by-Step Configuration

1. Enable HTTP Server

conf t
ip http secure-server
ip http authentication local
username admin privilege 15 secret admin123

2. Enable RESTCONF

restconf

3. Verify REST API Endpoints

Use Postman:

• Method: GET
• URL: https://<router-ip>/restconf/data/ietf-interfaces:interfaces
• Auth: Basic Auth (admin/admin123)
• Headers:
  • Accept: application/yang-data+json
  • Content-Type: application/yang-data+json

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Sample JSON Output from API

{
  "ietf-interfaces:interfaces": {
    "interface": [
      {
        "name": "GigabitEthernet1",
        "type": "iana-if-type:ethernetCsmacd",
        "enabled": true
      }
    ]
  }
}

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Troubleshooting Tips

Problem	Cause	Solution
API returns 401 Unauthorized	Wrong credentials	Check username/password or token
API returns 404 Not Found	Wrong endpoint	Validate the URL path
Empty response	Feature not enabled	Check if RESTCONF is enabled
Connection refused	HTTPS not enabled	Enable ip http secure-server
JSON output unreadable	Missing headers	Ensure correct Accept header

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FAQs on REST API Basics for Cisco

1. What is a REST API and how is it used in Cisco networking?

Answer:
A REST API (Representational State Transfer) is a web-based architectural style that uses standard HTTP methods (GET, POST, PUT, DELETE) for communication. In Cisco networking, REST APIs are used to interact programmatically with devices like Cisco IOS XE, NX-OS, DNA Center, and Meraki. This enables automation, configuration, monitoring, and troubleshooting without relying on CLI or manual intervention.

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2. Which Cisco platforms support REST APIs?

Answer:
Cisco has enabled REST APIs across multiple platforms, including:

• IOS XE – via RESTCONF and NETCONF (e.g., Catalyst 9000)
• NX-OS – via NX-API REST
• DNA Center – full-featured REST API for SDN management
• Meraki Dashboard – cloud-managed REST API for configuration and monitoring
• Webex, ACI, and Umbrella – also support REST APIs for programmability
  Each platform may have different authentication methods and capabilities.

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3. What’s the difference between RESTCONF, NETCONF, and NX-API?

Answer:

• RESTCONF – A RESTful protocol using YANG models over HTTPS, ideal for IOS XE platforms
• NETCONF – XML-based RPC protocol for configuration, often used with automation tools like Ansible
• NX-API REST – REST interface specific to NX-OS, often JSON or XML based
  All serve the purpose of device programmability but differ in syntax, flexibility, and performance.

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4. How do I authenticate to a Cisco device’s REST API?

Answer:
Authentication methods depend on the platform:

• Basic Auth (username/password) – Common on RESTCONF and NX-API
• Token-Based Auth – Used by Cisco DNA Center and Meraki
• OAuth2.0 – Used in Webex and some advanced integrations
  Ensure HTTPS is enabled and credentials are secured. Most platforms support secure TLS communication.

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5. What tools can I use to test and explore Cisco REST APIs?

Answer:
Popular tools for testing include:

• Postman – Ideal for manual REST API testing with GUI
• cURL – Command-line tool for scripting HTTP requests
• Python + Requests Library – For writing automation scripts
• Cisco API Console & API Docs – For platform-specific REST API documentation
  These tools help you send API requests, inspect responses, and automate workflows.

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6. What is a typical REST API call format to a Cisco device?

Answer:
A REST API call generally follows this format:

GET https://<device-ip>/restconf/data/native/interface
Headers:
  Content-Type: application/yang-data+json
  Accept: application/yang-data+json
  Authorization: Basic <Base64EncodedCreds>

You may receive a JSON or XML response, depending on headers. RESTCONF requires authentication and proper headers to succeed.

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7. What are some real-world use cases for REST APIs in Cisco networks?

Answer:

• Automated configuration of interfaces, VLANs, routing protocols
• Monitoring device status and operational data (e.g., CPU, memory, interface stats)
• Automating firmware upgrades or config backups
• Bulk provisioning of access points or switches
• Integrating with CI/CD pipelines for NetDevOps workflows
  These use cases save time, reduce human error, and scale operations.

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8. What’s the benefit of using JSON vs XML in Cisco REST APIs?

Answer:
While Cisco supports both JSON and XML, JSON is:

• Lighter and easier to read
• More Python-friendly and widely used in web applications
• Supported by most REST clients like Postman and Python scripts
  XML is still used in NETCONF and some legacy systems but JSON is preferred for REST-based automation.

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9. Are there any security risks with using REST APIs, and how can I mitigate them?

Answer:
Yes, security is a concern when exposing APIs on network devices. Key risks and mitigations:

• Credential Leakage – Always use HTTPS, avoid hardcoding passwords
• Unauthorized Access – Use role-based access control (RBAC) and tokens
• Rate Limiting/DoS – Apply API rate-limiting features where supported
• Logging & Auditing – Enable detailed logs for API access
  Security best practices are critical when using APIs in production.

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10. How do REST APIs relate to network automation tools like Ansible or Python scripts?

Answer:
REST APIs serve as the underlying communication channel for many automation tools:

• Python scripts use libraries like requests to send HTTP REST calls
• Ansible modules (like ios_config) may use RESTCONF under the hood
• Cisco DNA Center Ansible Collection uses REST APIs to control SDN fabric
  By learning REST APIs, you’re building foundational skills for scalable, tool-agnostic automation.

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YouTube Video Link

Watch the Complete CCNP Enterprise: RREST API Basics for Cisco Devices – Automate Smarter, Not Harder Lab Demo & Explanation on our channel:

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Final Note

Understanding how to differentiate and implement REST API Basics for Cisco Devices – Automate Smarter, Not Harder is critical for anyone pursuing CCNP Enterprise (ENCOR) certification or working in enterprise network roles. Use this guide in your practice labs, real-world projects, and interviews to show a solid grasp of architectural planning and CLI-level configuration skills.

If you found this article helpful and want to take your skills to the next level, I invite you to join my Instructor-Led Weekend Batch for:

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