7Sigma

Posted on Aug 28 • Edited on Sep 30

Why We Choose Rust for Modern Systems

#rust #distributedsystems #coding #development

Speed, safety, & seamless integration. We've built production systems in most major languages; but when correctness and resilience matter, Rust often wins.

TL;DR: Ecosystem often drives language choice, with TypeScript or Python winning for their rich libraries. But for critical infrastructure, Rust stands out: fast, predictable, safer by design, and portable across APIs, CLIs, and bindings, while protecting intellectual property from reverse engineering.

Rust is known for speed, safety, and compiling to machine code. That is the foundation. After building production systems in nearly every major language, we have seen Rust deliver advantages that go beyond its headline features. This is not about picking a favorite language. It is about choosing the right tool for systems that must be fast, safe, and resilient.

Well Known Advantages

Predictable performance: No garbage collector ensures steady latency under load.
Safety without compromise: Ownership and borrowing eliminate entire bug classes before runtime.
Smaller attack surface: Compiler guarantees reduce many vulnerability classes.
Compiled to machine code: Small optimized binaries start instantly, ideal for serverless, short-lived workers, and long-running services.

Cold Starts in Serverless: Rust vs TypeScript vs Python

Cold start latency matters for APIs, event processors, and other workloads that need to scale to zero and respond instantly.

Rust: Independent benchmarks show Rust to be among the fastest AWS Lambda runtimes.
- Scanner.dev measured Rust cold starts in the 20–50 ms range, sometimes as low as ~43 ms for small binaries (Serverless Speed — Rust vs Go, Java, Python in AWS Lambda Functions).
- FourTheorem reports Rust Lambdas typically cold start in 10–50 ms under real conditions (High Performance Lambdas with Rust).
TypeScript (Node.js): Cold starts vary widely with package size and initialization code.
- Xebia’s AWS Lambda benchmarking observed 200–600 ms cold starts for typical Node.js functions, increasing with larger dependencies (AWS Lambda Benchmarking).
- AWS notes that JavaScript runtimes can have noticeably longer initialization when bundles grow large (AWS Lambda Runtime Environment).
Python: Often slower to spin up due to interpreter load and dependency import time.
- Xebia found 300–700 ms cold starts were common for Python, sometimes exceeding a second for heavier packages (AWS Lambda Benchmarking).
- AWS documentation states cold starts can range “from under 100 ms to over 1 s” depending on runtime and package size (AWS Lambda Runtime Environment).

Cold starts are highly workload-dependent, but across multiple independent tests Rust reliably sits at the low end of latency compared to garbage-collected or dynamically typed languages.

Practical Strengths in Production

Mature tooling: Cargo and crates.io rival Node.js with a robust package manager, built-in testing, and documentation.
Operations-ready: Single static binaries create small containers, streamline deployments, and simplify scaling.
Reusable cores: One library powers services, CLIs, and workers without duplicating logic.

Calculations That Stay Fast and Correct

Rust excels in real-time, high-integrity computations:

Trading engines and risk models with predictable performance.
Data pipelines leveraging zero-copy parsing and SIMD acceleration for high throughput.
Cryptography, hashing, and security primitives with compile-time correctness.

This ensures performance is reliable and bugs are caught before runtime, reducing production issues.

Always Ship a CLI

Every Rust core includes a CLI interface:

Developers: Call flows locally, replay events, and seed data for testing.
Operations: Run migrations, backfills, and production runbooks.
Consistency: One code path for library, CLI, and API.

This approach accelerates development and empowers operations teams.

Capabilities That Change How We Architect

Rust enables flexible, secure, and interoperable system designs.

Multi-language export:
- WebAssembly (WASM): Run Rust in browsers and at the edge with near-native speed. Unlike JavaScript, logic ships compiled, harder to skim or copy.
- Swift bindings (UniFFI): Power native iOS and macOS apps with Rust engines.
- TypeScript/Node add-ons: Handle heavy compute in JavaScript environments.
IP protection: Shipping WASM or native code raises the barrier for competitors, safeguarding sensitive algorithms from reverse engineering.
Contract-first development: Using serde with JSON schemas, we define data contracts once, validate them at every boundary, and auto-generate tests and documentation.
Unified tools: A single Rust core includes a CLI for development and operations, ensuring consistency.

// Rust core
#[wasm_bindgen]
pub fn calculate_risk(portfolio: &str) -> f64 {
    // Complex risk calculations
    // Runs in browser, Node, or native
}

// TypeScript consumer
import { calculate_risk } from './rust_core';
const risk = calculate_risk(portfolio);

Rust in Action at 7Sigma

At 7Sigma, we use Rust to build high-performance, secure systems. Examples include:

Orbital mechanics and star position engines for high-precision spatial math.
Volatility Taker, a trading engine capturing opportunities within volatility bands.
JSON-first APIs and libraries with schema validation and serde integration.
Cross-platform libraries exported as WASM and Swift bindings for browser, edge, and mobile.
High-throughput data processing, including real-time sentiment analysis with zero-copy parsing and SIMD acceleration.
Embedded large language models (LLMs) for inference and data-driven pipelines.

Adoption Realities

Rust has a learning curve. Its ownership and lifetime concepts require a shift in thinking, but compiler guidance, clear documentation, and strong community support make onboarding faster than expected. The ecosystem is smaller than Python or JavaScript but growing rapidly. Cargo simplifies dependency and build management, driving Rust’s momentum.

Developers are taking notice. The 2025 Stack Overflow Developer Survey ranks Rust as the most admired language, with 72 percent of developers wanting to work with it, followed by Gleam (70 percent), Elixir (66 percent), and Zig (64 percent). Cargo is the most admired cloud development tool, with 71 percent approval.

Where Rust Fits and Where Other Stacks Lead

Rust excels in specific domains but is not a universal solution.

Ideal for:
- Trading engines and risk models requiring predictable performance.
- Low-latency APIs and secure gateways with minimal vulnerabilities.
- High-throughput ETL and streaming data with zero-copy efficiency.
- Cryptography and security primitives with compile-time guarantees.
- AI infrastructure, including vector math, streaming I/O, and embedded LLMs.
- Serverless workloads needing fast cold starts.
Better elsewhere:
- Python for rapid ML and AI prototyping with rich libraries.
- TypeScript for complex UI and web backends with robust frameworks.
- Elixir for fault-tolerant, highly concurrent domains such as payments and banking.
- Go for simple, networked services with straightforward concurrency.

Rust is for the core you must trust: fast to start, safe to run, resilient under load, and portable across platforms.

The Balance

Rust does not replace every tool. Sometimes Python’s rich libraries, TypeScript’s front-end frameworks, or Go’s simplicity are the better choice. Anchoring critical systems in Rust ensures safer, faster code with clean interoperability, delivering fewer production surprises and greater confidence in scaling. Rust is a reliable primitive you can wrap as JSON APIs, CLIs, bindings, and libraries that integrate seamlessly with your stack.

Ecosystem where it matters. Rust where it counts.

Rust isn't just another systems language. It's a reliable primitive you can wrap as JSON APIs, CLIs, bindings, and libraries that play well with the rest of your stack.

That balance, ecosystem where it matters, Rust where it counts, is how we ship systems that don't just run, but last.

About 7Sigma

7Sigma was founded to close the gap between strategy and execution. We partner with companies to shape product, innovation, technology, and teams. Not as outsiders, but as embedded builders.

From fractional CTO roles to co-founding ventures, we bring cross-domain depth: architecture, compliance, AI integration, and system design. We don’t add intermediaries. We remove them.

We help organizations move from idea → execution → scale with clarity intact.

Don't scale your team, scale your thinking.

Learn more at 7sigma.io

Original post at 7Sigma Blog

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