---
title: Principles | SevenLabs
description: How we build financial systems: correctness, performance and operability, and what each one means in practice.
url: https://www.sevenlabs.org/principles
---

# Our engineering principles

Every system we build has to get three things right. This is what each one means, and how we hold ourselves to it.

## Correctness

It does what it should, including under failure and attack.

In financial software a bug costs money, and other people see it happen. So we design the failure cases first, then build the system to handle them.

### How we do it

- We write down the system’s invariants before writing code.
- We test against real data, not only fixtures.
- We test failure deliberately.
- We review existing systems the same way.
- Formal verification on the parts where an error would be unrecoverable.

## Performance

It holds up under real load, where latency costs money.

Speed claims mean little without numbers, so we measure before and after every change, on real traffic.

### How we do it

- We find the actual bottleneck before optimizing anything.
- Under load, nothing is silently dropped.
- Every performance change comes with its measurements.

## Operability

Your team can run it, monitor it, debug it and change it.

A system only one firm understands is a risk. We build it so your engineers can own it.

### How we do it

- Every system ships with metrics and tracing.
- Recovery is defined up front.
- The code is written to be read and changed.
- We hand over properly.

---

SevenLabs, an engineering firm for onchain finance. [Talk to an engineer](https://calendly.com/sevenlabs_/intro-call), or see the [site map](https://www.sevenlabs.org/llms.txt).