Quick answer: Network engineers use Python because it is easy to read, runs everywhere, and has a mature ecosystem built specifically for networks β Netmiko and NAPALM for SSH, requests for REST APIs, ncclient for NETCONF, Nornir for running jobs across hundreds of devices, and pyATS for testing. Every major vendor (Cisco, Juniper, Arista, Palo Alto, Fortinet) ships Python SDKs, and Ansible itself is written in Python. Learning it turns repetitive CLI work into scripts that run in seconds and makes you far more employable.
This article covers the concrete benefits of Python for networking, the use cases teams automate first, which libraries map to which jobs, how Python compares with the alternatives, and the mistakes that slow down engineers moving from the CLI to code.
The problem Python solves for network teams
A mid-sized company might run 300 switches, 40 routers and a dozen firewalls. Changing the NTP server or auditing for a security advisory means touching every box. Manually, that is a week of copy-paste with a real chance of a typo taking down a site. In Python, it is a loop over an inventory file that finishes during a coffee break and logs exactly what changed.
That shift β from “operate devices” to “program the network” β is what the industry calls NetDevOps, and Python is its default language.
Eight reasons Python fits network engineering
- Readable syntax. Python looks like structured English. An engineer with no programming background can read a 40-line Netmiko script on the first pass, which matters when the whole team reviews scripts.
- Purpose-built libraries. Netmiko, NAPALM, Nornir, Scapy, PySNMP, ncclient and pyATS exist because the networking community built them. No other language has this depth.
- Vendor support. Cisco DevNet, Juniper PyEZ, Arista eAPI, Meraki, Palo Alto’s
pan-os-pythonand Fortinet all publish official Python SDKs and free sandboxes. - Interpreted and interactive. No compile step. Open a REPL, connect to a lab switch, try a command, see the result.
- Runs everywhere. Linux jump hosts, Windows laptops, macOS, containers, and even on the devices themselves β Cisco IOS-XE, NX-OS and Arista EOS have on-box Python interpreters.
- Data handling built in. JSON, YAML and CSV are one import away. Device inventories, API responses and configuration templates (via Jinja2) all become native Python structures.
- Integrates with everything. Ansible modules, Git hooks, CI/CD pipelines, Slack bots, ServiceNow, Grafana β Python glues them together.
- Huge community and job market. Tutorials, Stack Overflow answers and open-source examples are everywhere, and “Python” appears in the majority of network automation job descriptions in India and abroad.
Real use cases teams automate first
| Use case | What the script does | Typical libraries |
|---|---|---|
| Configuration backup | Nightly show running-config from every device, committed to Git |
Netmiko, GitPython |
| Bulk configuration changes | Render config from a Jinja2 template per device and push it | Jinja2, Netmiko or NAPALM |
| Compliance audit | Check every device for required ACLs, SNMPv3, logging and banner text | Netmiko, TextFSM, pandas |
| Monitoring and alerting | Poll interface counters and post to Slack or Teams when errors rise | PySNMP, requests |
| Pre/post change validation | Snapshot routing tables before and after a change and diff them | pyATS/Genie, NAPALM |
| API-driven controllers | Create sites, VLANs and policies in Meraki, DNA Center or cloud VPCs | requests, vendor SDKs, boto3 |
For a deeper look at the monitoring row, read Network Monitoring with Python: Using PySNMP and Netmiko.
Hands-on: two scripts that show the payoff
Both examples use Python 3.9+. Install the dependencies with pip install netmiko jinja2. Credentials come from environment variables β never hard-code them.
Example 1 β audit NTP and logging across many devices in parallel:
import os
from concurrent.futures import ThreadPoolExecutor
from netmiko import ConnectHandler
REQUIRED = ["ntp server 10.0.0.10", "logging host 10.0.0.20"]
hosts = ["10.1.1.1", "10.1.1.2", "10.1.1.3", "10.1.2.1"]
creds = {"username": os.environ["NET_USER"], "password": os.environ["NET_PASS"]}
def audit(host):
try:
with ConnectHandler(device_type="cisco_ios", host=host, **creds, conn_timeout=10) as conn:
config = conn.send_command("show running-config | include ntp|logging")
missing = [line for line in REQUIRED if line not in config]
return host, "OK" if not missing else f"MISSING: {missing}"
except Exception as exc: # one bad device must not stop the audit
return host, f"ERROR: {exc.__class__.__name__}"
with ThreadPoolExecutor(max_workers=10) as pool:
for host, result in pool.map(audit, hosts):
print(f"{host:<14} {result}")
Ten threads audit ten devices at once; 300 devices finish in about the time it takes to log into three by hand.
Example 2 β generate configuration from a template and data:
from jinja2 import Template
template = Template("""\
{% for vlan in vlans %}
vlan {{ vlan.id }}
name {{ vlan.name }}
{% endfor %}
interface {{ uplink }}
description Uplink to {{ core }}
switchport mode trunk
switchport trunk allowed vlan {{ vlans | map(attribute='id') | join(',') }}
""")
site = {
"core": "core1",
"uplink": "GigabitEthernet1/0/48",
"vlans": [{"id": 10, "name": "USERS"}, {"id": 20, "name": "VOICE"}, {"id": 99, "name": "MGMT"}],
}
config_lines = template.render(**site).splitlines()
print("\n".join(config_lines))
# Push with Netmiko: conn.send_config_set(config_lines)
Separating data (the site dictionary, usually loaded from YAML) from the template means a new branch office is a 10-line data file, not a 200-line hand-typed config.
Python versus the alternatives
| Option | Strengths | Limitations for networking |
|---|---|---|
| Python | Readable, richest network library ecosystem, vendor SDKs, data handling | Slower than compiled languages (rarely matters for automation) |
| Ansible | Agentless, declarative YAML, large module library, no coding required | Hard to express complex logic; you still end up writing Python modules |
| Bash / Expect | Available everywhere, quick for one-liners | Fragile parsing, poor error handling, no structured data |
| Go | Fast, single binary, used in gNMI tooling and some controllers | Steeper learning curve, far fewer network libraries and examples |
| PowerShell | Excellent on Windows and for Microsoft infrastructure | Limited network-vendor support outside Windows |
Python and Ansible are complementary: teams run Ansible playbooks for standard changes and Python for anything with logic, loops or data processing.
Six mistakes network engineers make when learning Python
- Trying to learn “all of Python” first. You need variables, lists, dictionaries, loops, functions,
withblocks and exception handling. Start automating within the first week. - Screen-scraping with regex when a parser exists. Netmiko’s
use_textfsm=True, Genie parsers and vendor APIs give you structured data for free. - Hard-coding passwords. Use environment variables, a
.envfile ignored by Git, or a vault. - Testing on production. Build a lab with CML, EVE-NG, GNS3 or Containerlab, or use Cisco DevNet’s free sandboxes.
- Not using version control. Scripts and configs belong in Git. It is your audit trail and your undo button.
- Ignoring error handling. One unreachable device must not crash a 300-device job. Catch exceptions per device and report them.
Frequently asked questions
Do I need a computer science degree to learn Python for networking?
No. Most network automation engineers learned Python on the job. Your networking knowledge is the hard part; Python is the easier skill to add on top.
Will automation replace network engineers?
It replaces repetitive tasks, not the people who understand the network. Engineers who can also script are the ones designing the automation, and they are paid accordingly.
Should I learn Ansible or Python first?
Python. Ansible is easier to start with, but when a playbook cannot do what you need, the solution is a Python module. Understanding Python makes you effective with both.
Key takeaways
- Python is the default language of network automation because of readability, vendor support and a library for every job.
- Start with high-value, low-risk tasks: backups, audits and read-only API queries.
- Separate data from logic with YAML and Jinja2, keep secrets in the environment, and store everything in Git.
- Python plus networking knowledge is one of the strongest skill combinations in today’s infrastructure job market.
Ready to add Python to your networking career? The Techknowledgehub Python & Data Science course starts from zero and takes you through Python fundamentals, APIs, JSON, data handling and real automation projects with live mentor support and placement assistance. For free tutorials, subscribe to our YouTube channel.
