What is Algo Trading and how is it changing the financial market?
Algorithmic trading is completely changing today’s financial market. In this, trading is done with the help of computer programs and quantitative techniques, which allow traders to make decisions very quickly and accurately. Especially when you talk about high frequency trading (HFT), every microsecond is precious.
In this blog, we have explained the importance of tools like Python and Freqtrade in Algo Trading and how they make trading more effective and profitable.

What are Python Decorators and why is their use important in Algo Trading?
Decorators in Python are a technique that takes a function as input and adds some additional functions (such as logging, timing, etc.) to it and then returns it by creating a new function. Since functions in Python are First Class Objects, we can pass, return or store them as a variable.
Python Decorators are used in several important tasks in Algo Trading:
1. Logging – Track function calls
Algo Trading has thousands of trading strategies. If any error occurs in a strategy, it can be difficult to track it. With the help of Python Decorators, we can do automatic logging, so that we can easily know which function failed when and how.
2. Timing – Measure the execution time of the function
Timing is everything in Algo Trading, especially HFT. Every microsecond can change the outcome of trading. With Decorators in Python, we can measure the execution time of a function and optimize it so that our system can trade faster.
3. Retry Mechanism – Automatic Retry on temporary failure
Sometimes API or network may fail in Algo Trading. In such a situation, it is not possible to retry manually again and again. With the help of Python Decorator, you can create a mechanism that automatically retries the function when a specific exception occurs.
4. Access Control – Give permission only to Authorised Users
There are many types of users in Algo systems – like Admin, Analyst, Viewer etc. With the help of Decorators, you can add such conditions to the function so that only Authorised users can access certain functions.
5. Resource Management – Use resources properly
Algo trading systems often have database connections, file handling or API calls. If these are not managed properly, resource leakage can occur. With Decorators, you can ensure that resources are opened and closed properly.
A simple example of Python Decorators in Algo Trading
Suppose you have a function trade_details() which prints trading details. Now you want that when this function runs, stars or any other design should be printed above and below it, so that the output looks good. For this, you can create a decorator that first prints stars, then calls trade_details() and finally prints stars again.
This is a basic visual decoration, but in reality, you can also do logging, timing, exception handling, etc. with this logic.
Decorate a Strategy using Freqtrade and Python
Suppose you are creating a function called sma_strategy(trade_data) that calculates the SMA (Simple Moving Average) of a stock. Now suppose you have 1,000 such strategies, and you want to add logging or timing to each one.
It is better to create a decorator once and apply it to all the strategies rather than changing each function separately. This will not only make your code easier to maintain, but if you want to make any changes in the future, then all the functions can be affected by making changes in one place.
Why are Python Decorators important in Algo Trading?
- Makes code clean and maintainable
- Helps with automatic logging and debugging
- Helps track execution time
- Makes user access control and resource management easier
Supports scalable and modular system development
Time and performance are everything in Algo Trading, and Python Decorators are a tool that helps you improve your code. Whether it is measuring execution time, logging or retry mechanism — decorators prove to be helpful everywhere.
If you are learning Algo Trading with Python and tools like Freqtrade, then it is important for you to understand Decorators well. In the coming days, we will discuss more Python Libraries like Pandas, NumPy and TA-Lib, which can take Algo Trading to the next level.
Watch this Day 19 video tutorial
Day 19: Decorators