[Day#1c PyATS Series] Why pyATS? Why not just stick to Netmiko / NAPALM / Paramiko which are easier? [Python for Network Engineer]

Many network engineers ask: “Why should I learn pyATS when simpler options like Netmiko or NAPALM already exist?”

Let’s break it down.

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What Netmiko and NAPALM Offer

Netmiko and NAPALM are excellent tools for:

• Connecting to network devices over SSH
• Sending CLI commands (like show ip int brief)
• Retrieving raw text output

These libraries are lightweight and ideal for ad-hoc automation or one-off scripts.

However, when moving towards production-grade, large-scale network validation, they start to show limitations.

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What pyATS Brings to the Table

Feature	Netmiko/NAPALM	pyATS
Multi-vendor Support	Limited, driver-dependent	Extensive (Cisco, Arista, Juniper, Palo Alto, Fortinet)
Structured Output	Raw text, manual parsing	Genie parsers provide structured JSON-like data
Testing Framework	Must build from scratch	Built-in testing with Easypy jobs and reusable scripts
Parallel Connections	Requires threading setup	Native support for concurrency
Reusable Testbeds	Not abstracted	Testbed abstraction via testbed.yml
Reporting and Logs	Print to console	Generates HTML, JSON, and CLI reports out of the box
Scalability	Complex to scale	Designed for hundreds of devices simultaneously

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Why pyATS is Worth Learning

pyATS is Cisco’s official network automation testing framework, built to handle vendor-agnostic validation across enterprise and service provider networks.

With pyATS, you can:

• Diff pre- and post-change configurations automatically
• Validate routing protocols, interface statistics, or any state across hundreds of devices
• Produce professional-grade HTML and JSON reports for NOC or management teams

This level of automation is not practical with raw Netmiko/NAPALM scripts unless you build significant scaffolding yourself.

from pyats.topology import loader
import os

# Load testbed
testbed = loader.load('testbed.yml')

# Clean up old known_hosts entries
for dev in testbed.devices.values():
    ip = dev.connections['cli']['ip']
    os.system(f'ssh-keygen -f "~/njsagar/.ssh/known_hosts" -R "{ip}"')

# Proceed with connection
device = testbed.devices['R01']
device.connect()

# Ping test
result = device.ping('8.8.8.8')
print("Ping result:", result)

device.disconnect()

testbed:
  name: my_testbed
devices:
  R01:
    os: iosxe
    type: router
    connections:
      defaults:
        class: unicon.Unicon
      cli:
        protocol: ssh
        ip: 192.168.1.1
    credentials:
      default:
        username: admin
        password: cisco

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Is pyATS Harder to Use?

Yes, pyATS has a steeper initial learning curve:

• Requires setting up virtual environments and dependencies
• Needs understanding of testbed abstractions (testbed.yml)

But once set up, you spend less time writing repetitive code and more time automating actual network validations.

In contrast, Netmiko scripts often grow unwieldy as network size increases.

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Real-World Example

Task: Validate OSPF neighbor states on 400 routers and flag any failures.

• Netmiko Approach: Write scripts to connect to each router, send commands, parse text, and manually compare outputs.
• pyATS Approach: Load testbed.yml, run pyats learn ospf, get structured data instantly, and assert states.

Result: With pyATS, the same validation takes a fraction of the code and time.

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Why It Matters

As networks grow in size and complexity, traditional manual validation and even basic automation scripts struggle to keep up. Organizations today demand vendor-agnostic, scalable, and reliable automation frameworks that can handle hundreds or thousands of devices efficiently.

This is where pyATS stands out. Unlike lightweight libraries such as Netmiko or NAPALM, pyATS provides:

• A unified API for managing devices across multiple vendors
• Built-in testing workflows to catch issues before they impact production
• Structured data output for seamless integration with dashboards and reports
• Scalability from small labs to large enterprise networks

For network engineers, adopting pyATS means moving beyond ad-hoc scripts toward enterprise-grade automation practices. It enables faster validation cycles, reduces human errors, and supports DevNet-style CI/CD pipelines for network changes.

If you’re serious about network automation, pyATS is not just another tool—it’s a mindset shift. It prepares you for the future of infrastructure as code, where testing and validation are no longer optional.

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Ready to Level Up?

Stop writing one-off scripts that don’t scale. Start building automation workflows that deliver real business impact. Learn pyATS today and future-proof your career in the world of network automation.

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FAQS

1. Why should I choose pyATS over Netmiko or Paramiko for network automation?

Netmiko and Paramiko are great for basic SSH-based automation but pyATS offers a complete testing framework with built-in parsers, robust test harness, multi-vendor support, and the ability to perform pre/post-change validations automatically.

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2. Can pyATS do everything that Netmiko or NAPALM can?

Yes, and more. While Netmiko focuses on sending CLI commands and NAPALM abstracts config/state retrieval, pyATS combines device connectivity, parsing, structured outputs, test suites, job management, and integration with CI/CD workflows.

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3. Is pyATS harder to learn compared to Netmiko or Paramiko?

Initially, pyATS may feel more complex because it introduces a testing framework mindset. However, its automation-first design reduces long-term maintenance and manual scripting efforts, making it easier for large-scale projects.

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4. How does pyATS handle multi-vendor environments compared to NAPALM?

pyATS, combined with Genie parsers, auto-detects OS types and parses command outputs into vendor-agnostic Python dictionaries. NAPALM supports multiple vendors but with limited feature parity across platforms.

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5. Can I use pyATS and Netmiko/NAPALM together?

Yes. pyATS can coexist with Netmiko or NAPALM scripts. For example, you can use Netmiko for ad-hoc configuration pushes and pyATS for structured testing and validation.

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6. Does pyATS support API-based interactions like RESTCONF/NETCONF?

Yes. pyATS supports multiple connection types, including CLI, NETCONF, RESTCONF, and gNMI. This makes it future-proof compared to purely SSH-based libraries like Paramiko.

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7. Is pyATS suitable for CI/CD network automation pipelines?

Absolutely. pyATS was designed for continuous testing, allowing network engineers to integrate automated health checks, rollback validations, and compliance testing into CI/CD workflows.

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8. What advantages does pyATS bring for Python for Network Engineer learners?

pyATS provides structured learning for network testing, parsing, and automation that scales from small scripts to enterprise test suites. It’s an essential skill for network engineers transitioning to DevNet roles.

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YouTube Link

Watch the Complete Python for Network Engineer: Why pyATS? Why not just stick to Netmiko / NAPALM / Paramiko which are easier? [Python for Network Engineer] Lab Demo & Explanation on our channel:

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Join Our Training

Learning how to build pyATS testscripts is just the beginning. To become proficient in Python for Network Engineer automation, you need structured guidance and real-world practice.

Trainer Sagar Dhawan offers a 3-month instructor-led training covering Python, Ansible, API integrations, and Cisco DevNet skills. This program is designed for network engineers who want to master automation tools and advance their careers.

Join the training here and take your first step towards becoming a network automation expert.

Enroll Now & Future‑Proof Your Career
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