IronSoftware

Posted on Jan 22

Compare C# to Python - Which Language Should You Choose?

#dotnet #csharp

Our startup debated tech stacks. Python fans cited rapid development. C# advocates emphasized performance. Both were right. Both were wrong.

Here's the honest comparison nobody tells you.

Performance: C# Wins (Dramatically)

Benchmark: Same algorithm, both languages

// C# (compiled)
var result = numbers.Where(n => n % 2 == 0).Sum();
// Execution: 2 seconds

# Python (interpreted)
result = sum(n for n in numbers if n % 2 == 0)
# Execution: 52 seconds

C# is 10-50x faster for compute-heavy tasks. Compiled vs interpreted makes this difference.

Python's dynamic typing checks every variable at runtime. C# determines types at compile time. Less overhead, faster execution.

Development Speed: Python Wins

Write a web API:

Python (Flask):

from flask import Flask
app = Flask(__name__)

@app.route('/api/users')
def get_users():
    return {'users': []}

app.run()

5 lines. Running in seconds.

C# (ASP.NET Core):

var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();

app.MapGet("/api/users", () => new { users = new string[] { } });

app.Run();

Also concise (modern .NET), but requires project setup, SDK, more ceremony.

Python: Faster to prototype. C#: Faster to execute.

When to Use Python

Data science / Machine learning:

TensorFlow, PyTorch, scikit-learn
Jupyter notebooks
pandas, NumPy ecosystem

import pandas as pd
import tensorflow as tf

# Load data, train model, done
model = tf.keras.Sequential([...])
model.fit(data)

Python dominates ML. Period.

Scripting / Automation:

#!/usr/bin/env python3
import os

for file in os.listdir('.'):
    if file.endswith('.log'):
        os.remove(file)

Quick scripts without compilation.

Web development (non-.NET):

Django (full-featured)
Flask (microframework)
FastAPI (async, modern)

Python web frameworks are mature, easy to learn.

When development speed > execution speed:

Prototypes
Internal tools
Data analysis
Research projects

I use Python for data pipelines, one-off scripts, ML experiments.

When to Use C

Enterprise applications:

// Type safety, compile-time errors
public class Order
{
    public required int OrderId { get; set; }
    public required decimal Total { get; set; }
}

// Compiler catches errors before runtime

Large codebases benefit from static typing. Refactoring is safer.

Game development:

Unity (C# is the primary language)
3D graphics performance matters

void Update()
{
    // Runs 60+ times per second
    // Performance critical
    transform.position += velocity * Time.deltaTime;
}

Python would stutter. C# handles it smoothly.

Windows desktop apps:

WPF, WinForms, MAUI
Native Windows integration
Better performance than Electron

High-performance backends:

// ASP.NET Core handles 7M+ requests/sec
// (TechEmpower benchmarks)
app.MapGet("/", () => "Hello World");

Python (even with Gunicorn) tops out around 100K req/sec.

When execution speed > development speed:

Financial systems
Real-time processing
High-traffic APIs
Performance-critical services

I use C# for production APIs, document processing (IronPDF), enterprise SaaS.

Ecosystem Comparison

Python strengths:

ML/AI libraries (TensorFlow, PyTorch)
Data science (pandas, NumPy, Jupyter)
Scientific computing (SciPy)
Massive package repository (PyPI)

C# strengths:

.NET ecosystem (ASP.NET, EF Core, MAUI)
Unity game engine
Azure integration
Enterprise libraries
Visual Studio (best IDE, period)

Both have:

Web frameworks
Database ORMs
Testing frameworks
Package managers (pip vs NuGet)

Learning Curve

Python: Easier for beginners

# Simple, readable
def greet(name):
    return f"Hello, {name}!"

print(greet("World"))

Minimal syntax. Looks like pseudocode.

C#: Steeper initially

public class Program
{
    public static void Main(string[] args)
    {
        Console.WriteLine(Greet("World"));
    }

    public static string Greet(string name)
    {
        return $"Hello, {name}!";
    }
}

More ceremony. But scales better to large projects.

Python: 2-4 weeks to productivity
C#: 4-8 weeks to productivity

Salary & Job Market

Average salaries (2025, USA):

Python: $105k-130k
C#: $110k-140k

C# slightly higher (enterprise premium).

Job availability:

Python: More startups, data science, academia
C#: More enterprises, finance, government

Both have strong demand.

Typing Systems

Python: Dynamic

x = 5       # int
x = "hello" # now a string (allowed!)

Flexible but error-prone. Type hints help (optional):

def add(a: int, b: int) -> int:
    return a + b

C#: Static

int x = 5;
x = "hello"; // Compile error!

Catches errors early. Refactoring is safer.

Concurrency

Python: GIL (Global Interpreter Lock)

# Multithreading doesn't truly parallelize (CPython)
# Use multiprocessing instead

GIL limits Python's parallel processing. Workarounds exist but add complexity.

C#: True threading

// Parallel processing, async/await
await Task.WhenAll(tasks);

C# handles concurrency elegantly. Async/await is fantastic.

Deployment

Python challenges:

Dependency management (virtualenv, poetry)
Version conflicts ("works on my machine")
Slower startup times

C# advantages:

Self-contained executables
Docker-friendly
Native AOT (single-file, fast startup)

C# deployment is cleaner for production systems.

Real-World Use Cases

Python wins:

Data pipelines at Netflix
Instagram backend (Django)
Dropbox sync engine
Scientific research
ML model training

C# wins:

Stack Overflow (ASP.NET)
Bing search backend
Xbox Live services
Financial trading platforms
Unity games (Hollow Knight, Cuphead)

Can You Use Both?

Yes! Common pattern:

Python: Data science, ML models, prototypes
C#: Production APIs, performance-critical services

# Python: Train ML model
model.fit(training_data)
model.save('model.pkl')

// C#: Serve predictions via fast API
app.MapPost("/predict", (InputData data) =>
{
    var prediction = model.Predict(data);
    return Results.Ok(prediction);
});

Use Python for what it's good at. Use C# where performance matters.

Which Should You Learn First?

Choose Python if you're:

New to programming
Interested in data science / ML
Building prototypes / MVPs
Working in academia / research

Choose C# if you're:

Targeting enterprise jobs
Building desktop apps
Interested in game development (Unity)
Want performance-critical skills

Pro tip: Learn both eventually. They complement each other.

My Recommendation

For this decade:

Start with Python (easier, faster feedback loop)
Learn fundamentals (variables, functions, OOP)
Pick up C# when you need:
- Performance
- Enterprise features
- Windows apps
- Unity game dev

Python teaches you to think. C# teaches you to scale.

Both are valuable. Neither is "better" universally.

Written by Jacob Mellor, CTO at Iron Software. Jacob created IronPDF and leads a team of 50+ engineers building .NET document processing libraries.

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