DeFi Software Engineer

Fionics; Greater London; On-site; GBP 90,000 - 130,000; Full time

Job summary

Fionics in London is seeking talented DeFi Software Engineers to help power live trading systems in a fast-moving market. This is an on-site role in a lean engineering team where you own features end-to-end and contribute to scalable production systems.

We welcome engineers from traditional tech firms or crypto, with strong systems programming skills in C++, Java, C#, Rust, or similar languages.

Qualifications

• Strong software engineering experience with production systems.
• Proficiency in C++, Java, C#, Rust, or similar systems languages.
• Track record of shipping real systems.
• Open to engineers from non-crypto backgrounds meeting the bar.

Responsibilities

• Build and ship production DeFi trading systems.
• Tackle technically demanding problems in a fast-moving market.
• Own your work end-to-end as a core team member.

Skills

C++

Java

C#

Rust

Tools

Docker

Kubernetes

Git

Linux

Job description

We're hiring DeFi Software Engineers for one of the leading DeFi trading operations in the world.

The team is small, technical, and operates at the top of the DeFi space. These are pure individual-contributor roles, with a genuine path toward trader/developer hybrid positions for those who want it.

What you'll do

• Build and ship production systems that power live DeFi trading


• Work on technically demanding problems in a fast-moving market


• Own your work end to end as a core member of a lean engineering team

What we're looking for

• Strong software engineering experience, ideally with production systems in a trading, fintech, or high-performance environment


• Proficiency in C++, Java, C#, Rust, or similar systems languages (this role does not use Python)


• A track record of shipping real systems, demonstrated through either professional experience or technical achievement


• Candidates currently within a short notice or non-compete period are well placed for this search


• Engineers from outside crypto (including top technology firms) are welcome where the engineering bar is met

Location

This role is fully on‑site in London. The full team is based there. Remote arrangements are not available for this position.

Compensation

Competitive with the top of the market, commensurate with experience.