Selecting a Tech Stack for Time-Critical Apps

"It’s not just about being fast."
When we talk about "Low Latency" in software engineering, we usually mean raw speed—how fast can I get a packet from A to B? But in algorithmic trading, there is a second, equally critical metric: Temporal Precision.
If a signal says "Execute CALL at 18:40:00," executing at 18:40:01 is a failure. Executing at 18:39:59 is a disaster.

I recently started building a "headless" trading bot—one that ignores charts and indicators entirely in favor of strict, text-based signals from Telegram. Here is how I approached the tech stack selection for a system where timing is everything, and why I eventually landed on Go

Before picking a language, I broke down exactly what the bot needed to do. It wasn't just "buying stocks." The requirements were:

1. Signal Parsing
2. The "Wait"
3. Concurrency
4. State Recovery (The Martingale Logic)

The Contenders: Python vs. Node.js vs. Go

1. Python Pros: The king of finance. Great libraries (Pandas, TA-Lib) and easy syntax.

The Dealbreaker: The Global Interpreter Lock (GIL) and Threading. While Python can do concurrency, managing precise microsecond-level timers while processing heavy logic in other threads can get messy. time.sleep() is blocking, and asyncio adds complexity when you need absolute precision rather than just "non-blocking" I/O

1. Node.js Pros: Amazing I/O handling. Perfect for listening to Webhooks.

The Dealbreaker: It's single-threaded by default. If the CPU gets busy calculating a Martingale recovery for one trade, it might block the event loop just long enough to delay the execution of another trade by a few milliseconds. In this game, those milliseconds cost money.

1. Go (The Winner) Why it won: Go combines the compilation speed of C with the ease of Python, but its superpower is Goroutines

In the end, Go won this round because it treated "Time" as a first-class citizen. It allowed me to build a bot that sleeps efficiently and wakes up aggressively.

But software engineering is about trade-offs. I’m writing this to document my thought process, but I’m eager to learn from yours.

So, a question for the comments: If you were building a system that had to execute a task at an exact millisecond, what stack would you pick today, and why?