Ethereum / Web3 Developer - Onsite/Hybrid Contractor (Krakow)

Senior Individual Contributor · Onsite/Hybrid Contractor · Kraków, Poland
 

Project description (direct hire)

We're a small, technically driven team building automated trading infrastructure on Ethereum. Our system detects arbitrage opportunities, routes trades across multiple third-party venues, and submits transactions to block builders for inclusion within a single block.

We're not a pre-revenue experiment. We're profitable, backed by world-class investors, and funded by our own live trading operations. That gives us the freedom to focus on what actually matters: expanding our strategies, sharpening execution, and building infrastructure that holds up when real money is on the line.

About the role

We're looking for a senior engineer to share ownership of our core trading logic and infrastructure. This is a hands-on individual-contributor role — no managing tickets, no proxy work. You'll be equally at home writing high-performance Rust, debugging a bundle-inclusion failure on-chain, and shipping services to Kubernetes in production.

You'll work across the full lifecycle of a trade: opportunity detection and scoring → quote aggregation across multiple routers → bundle construction → submission to block builders. Because the system handles real money, correctness, safety, and reliability are non-negotiable. You'll also own the risk-management layer — the automated short circuits and kill switches that monitor P&L in real time and pull trading back when thresholds are breached.

If you think about failure modes, rollback plans, and kill switches before the first line of code, you'll fit in well here.
 

What you'll own

• Trading strategy & execution. Design and implement arbitrage detection, opportunity scoring, and execution logic inside a Rust actor architecture that processes every new block in real time.
• Liquidity routing. Build and maintain integrations with aggregator APIs and self-hosted routers — quote collection, comparison, and optimal route selection across multiple liquidity sources.
• MEV bundle construction. Build and submit bundles to block builders, optimizing for gas efficiency, inclusion probability, and profit extraction, while interacting with multisig wallets and custom smart contracts.
• Automated risk controls. Develop systems that monitor balances, detect anomalies, and autonomously scale trading deployments down via the Kubernetes API when something looks wrong.
• Production infrastructure. Operate and evolve the platform end-to-end: deploy to AWS EKS, manage multi-account environments with Terraform, build Grafana dashboards, query logs through Loki, and own production troubleshooting.
   

Our stack

Rust · tokio · revm / Foundry · alloy / ethers-rs · PostgreSQL · Kubernetes (EKS) · AWS · Terraform · Grafana · Loki · Solidity / Gnosis Safe
 

What we're looking for

• 5+ years of software engineering experience, with a track record on complex backend systems and real ownership of technical domains from concept to production.
• Strong, demonstrable Rust expertise — async, concurrent code with tokio, trait-based abstractions, solid error-handling patterns, and comfort in performance-sensitive code paths.
• A real understanding of Ethereum's architecture: transactions, blocks, gas mechanics, ERC-20s, DEX mechanics, and the MEV supply chain (searchers, builders, relays). You understand why things are designed the way they are, not just how to call them.
• Experience building or operating systems that handle real money or critical infrastructure — you reason about failure modes, monitoring, kill switches, and rollback as a default.
• PostgreSQL proficiency: writing and optimizing queries, designing schemas for high-throughput time-series data, and managing migrations.

Nice to have

• Prior MEV experience: Flashbots, block builders, bundle submission, or searcher-strategy development.
• Hands-on work with Rust Ethereum libraries (alloy, ethers-rs) or EVM simulation tools (revm, Foundry/Anvil).
• Production Kubernetes (EKS) and AWS experience — deployments, secrets management, VPC networking, Terraform.
• Smart-contract development (Solidity/Foundry), especially Gnosis Safe modules or DeFi protocol integrations.
• Familiarity with DEX aggregator APIs and the trade-offs between on-chain and off-chain routing.

Location & engagement

This is a long-term contractor / subcontractor engagement. The role is anchored in Kraków — ideally you're based there. We'll also consider strong candidates elsewhere in Poland who can travel to Kraków regularly (roughly once a month, for a few days). Several of our team members are already on the ground there.

Why this one's worth your time

Most "Web3 developer" roles are CRUD with a wallet connect button. This isn't that. You'll own a real data and execution plane, ship to production, and see the direct P&L impact of your code on a system that's already live and profitable — with the autonomy of a senior contributor and none of the big-company bureaucracy.

If that sounds like your kind of problem, get in touch and we'll share the deeper technical details and terms.