7Sigma

Posted on Aug 28

Why We Choose Rust for Modern Systems

#rust #distributedsystems #coding #development

TL;DR: We've built production systems in most major languages. Each has strengths. Ecosystem often drives the choice; sometimes TypeScript or Python wins because of rich surrounding libraries and frameworks. But when we're building critical infrastructure, Rust consistently comes out ahead: fast, predictable, safer by design, and a portable primitive we can wrap with APIs, CLIs, and bindings - while raising the bar for reverse engineering and copycatting.

1) Why Rust Beats the Rest

Predictable performance: No GC pauses. Low, steady latency under load.
Safety without compromise: Ownership/borrowing kills entire bug classes before runtime.
Smaller attack surface: Stricter compiler guarantees = fewer exploits.
Ops friendly: Tiny static binaries, instant cold starts, easy to containerize and deploy.
Cross-platform by default: The same Rust core can be exported across ecosystems:
- WebAssembly for browsers and edge runtimes
- Swift bindings (via UniFFI) for iOS/macOS
- TypeScript bindings for Node or web apps
IP protection by design: Rust compiles to optimized machine code, not human-readable scripts. Unlike JavaScript, you’re not shipping raw logic into the browser for anyone to view-source and copy. Sensitive algorithms can ship as WASM or native binaries, raising the bar against reverse engineering.

Instead of rewriting critical logic in every stack, Rust lets you write once and reuse everywhere, a portable primitive that anchors the system while still playing well with others. Rust isn't always the right tool, but when correctness and resilience matter, it's the best bet.

2) Where Ecosystem Matters

Languages like TypeScript and Python thrive in certain domains:

TypeScript: Unmatched front-end frameworks, Node.js ecosystem, and community tooling.
Python: ML/AI research, data science, quick scripting with rich scientific libraries.
Go: Networking and infra teams with well-understood concurrency models.

We lean on these when ecosystem accelerates delivery more than raw performance or safety. But we anchor the system's critical core in Rust; where bugs or downtime cost real money.

3) Calculations That Stay Fast (and Correct)

Rust shines in real-time, high-integrity math:

Trading engines and risk models
Data pipelines with zero-copy parsing and SIMD acceleration
Crypto, hashing, and security primitives

Performance is predictable and correctness is enforced at compile time, less firefighting at runtime.

4) JSON Contracts as First-Class Citizens

Everything starts with the contract, and in our systems, the contract lives in Rust first.

Serde as the source of truth: We define schemas and data models directly in Rust using serde. This becomes the canonical contract that governs every API, event, and internal library call.
Validate at every boundary: Requests, responses, and events are checked against these serde-derived schemas to prevent drift and enforce consistency.
Docs and tests from the schema: We auto-generate documentation, fixtures, and regression tests so the contract stays synchronized.
Interop for free: From the serde definitions, we emit bindings and SDKs (TypeScript, Python, Swift, etc.), so consumers in other ecosystems align to the Rust-defined contract without duplication.

This approach flips the usual pattern: instead of JSON schemas bolted onto apps as an afterthought, Rust + serde defines the standard once, and every consumer plugs into it. The result is less drift, faster onboarding, and safer integrations.

5) Always Ship a CLI

Every Rust core gets a CLI interface:

Dev: Call flows locally, replay events, seed data
Ops: Migrations, runbooks, backfills in production
Consistency: One code path; library → CLI → API

Developers get speed, operators get power tools.

6) One Core, Many Faces

Rust makes it natural to export the same primitive across platforms:

Swift bindings (UniFFI): Native iOS/macOS apps powered by Rust engines
WebAssembly: Safe, near-native code in the browser and on the edge. Rust-to-WASM isn’t just about portability; it’s also about safety and opacity. Your core logic is shipped as a compiled module, not easily skimmed source, making it harder to clone or tamper with.
TypeScript bindings: Node apps call into Rust for heavy compute

Instead of rewriting core logic in every language, we write once, bind everywhere.

// 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);

7) Use Cases Where Rust Wins

Financial systems & trading infrastructure
Low-latency APIs and gateways
High-throughput ETL and streaming data
Security/crypto primitives
AI infra: preprocessing, vector math, streaming I/O

The Balance We Strike

We don't pretend Rust replaces everything. Ecosystem gravity is real; and sometimes the right choice is Python for quick ML prototyping or TypeScript for a rich UI layer.

But anchoring the system in Rust means:

Critical code is safer and faster
We can still interop cleanly with the ecosystems that matter
We get fewer production surprises and more confidence scaling

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.

Originally posted on the 7Sigma Blog

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

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