Founding Rust Engineer

Founding Rust Engineer

Paris or Remote (Europe)

About Twin

Twin is building fully autonomous AI agents that run real business operations.

You give a goal.

Twin figures out the steps.

It executes them end-to-end through APIs when they exist and through the browser when they don't.

This is not another chatbot.This is not another workflow builder.

We are building systems that can operate companies.

In the first months of beta, users have already deployed more than 100,000 agents running lead generation, customer support, operations, trading systems, e-commerce workflows, reporting, and entire service businesses.

Twin was founded by Hugo Mercier , CEO (founder of Dreem, $60M raised, 150+ employees, acquired) and João Justi, CTO (cryptography, compilers, virtual machines, distributed systems, ex-Zama) but also Julius de Bruijn, creator of Tiberius (3.3M downloads) and Patrick Tourniaire

We raised a $10M seed round led by LocalGlobe and are building with a small team of senior engineers.

Why join Twin?

• Work on one of the hardest problems in software: making AI agents reliable enough to run real businesses.

• Build from first principles: many of the core abstractions don't exist yet.

• Small team, massive ownership: your decisions directly shape the product, architecture, and company.

• Rust at the core, product at the center: not infrastructure for infrastructure's sake.

• Design systems for both humans and AI agents: a new software paradigm that barely exists today.

• Early enough to matter: every engineer has outsized impact on what Twin becomes.

What you'll work on

Most AI companies are focused on generating text or code.

We are focused on making AI systems reliably execute real work.

You will work on some of the hardest problems in autonomous agents:

• Browser execution at scale

• Low-latency communication between agent subsystems

• Reliable orchestration of long-running workflows

• Memory systems that improve over time

• Self-healing execution architectures

• Agent infrastructure that survives failures

• Product features used directly by customers

• Internal systems that AI coding agents can understand, operate and extend

Part of the challenge is not simply writing software.

The challenge is designing systems that remain understandable and modifiable by AI coding agents themselves. The way we build software internally increasingly assumes that both humans and coding agents will interact with the codebase.

What we're looking for

We're not looking for a "Rust developer".

We're looking for engineers who can own problems from idea to production.

You should probably have:

• Significant production Rust experience

• Strong systems thinking

• Experience building and operating real products

• High autonomy

• Ability to navigate ambiguity

• Interest in AI systems and LLMs

• Curiosity across the entire stack

You may come from:

• Infrastructure

• Databases

• Distributed systems

• Developer tools

• Browsers

• Networking

• Compilers

• Runtime systems

• AI infrastructure

What matters most is your ability to build robust systems and make good product decisions.

What tends to work well here

The engineers who thrive at Twin usually:

• Ship fast

• Take ownership without waiting for permission

• Care deeply about product outcomes

• Prefer building over discussing

• Enjoy working close to users

• Can move between infrastructure and product work

Many of the strongest engineers we know have backgrounds as founders, open-source maintainers, systems engineers, or product-minded infrastructure builders.

What won't work

This role is probably not for you if:

• You need detailed specifications before starting

• You prefer working on isolated technical components

• You only want to work on backend infrastructure

• You are uncomfortable making product decisions

• You dislike ambiguity

• You expect large-company processes

Examples of backgrounds we find exciting

• Engineers who built widely-used open-source infrastructure

• Early engineers from highly technical startups

• Systems engineers who became product builders

• Founders who built technical products from scratch

• Developers who combine deep technical expertise with strong product intuition

Compensation

Package 200 - 250 K

We're building for the long term and want people who think like owners.