Front-end Developer

The Firm

XTX Markets is a leading algorithmic trading company partnering with counterparties, exchanges and e-trading venues globally to provide liquidity in the Equity, FX, Fixed Income and Commodity markets. We provide consistent liquidity, helping market participants throughout the world obtain the best prices in the various assets classes we cover, regardless of changing market conditions.

At XTX Markets technology is our business and we are a diverse organisation which attracts outstanding talent from across all industry backgrounds. We are focused on teamwork and our people collaborate on all aspects of the business, working openly and with respect for each other, our clients and the market. Our culture is non-hierarchical and one where everyone is valued. We strive for excellence in everything we do.

The Role

You will be part of a small team which has responsibility within XTX for web-based GUI tools, which are a mixture of external and internal webapps. XTX is framework-agnostic when it comes to the development of web tools, and a lot of our simpler GUIs are written in vanilla Javascript (or Typescript), though familiarity with one or more common web frameworks is a plus.

You'll work alongside your team lead, as well as other engineers and Quants, developing and improving internal tools and frameworks. There are multiple development teams at XTX, but this role is within a central team that may provide assistance and development resource to these teams on a per-project basis.


  • Working on improvements to internal tooling libraries used by teams to deliver web-based GUIs
  • Using those libraries to create, maintain and improve our GUIs
  • Providing assistance to other developers and teams within XTX who use those libraries to manage their own GUIs
  • Helping end-users document bugs, and determining whether it lies within the framework, the team's implementation, or an upstream component
  • Collaborating with Team Lead to add/prune framework features
  • Working with the Infrastructure team to improve the way internal GUIs are served and secured
  • Advocating for GUI best-practice (security, design) across different teams

Essential Attributes

  • A pragmatic and approachable developer capable of working autonomously
  • High confidence using plain Javascript to handle and display real-time events
  • Have used at least one common JS framework (eg. React, Angular) on a project in production
  • Be familiar with common layout/design patterns for flows like data entry, analysis and export
  • Understand some basic UX research techniques; you have watched users use your GUIs and improved them as a result

Desirable Attributes

  • Have worked in a multi-disciplinary team on a project, including liaising with back-end or full stack developers on the design of an API for a client to consume
  • Have experience developing internal tools, and taking feedback from users of those tools
  • Have a brief portfolio of work, preferably with redacted screenshots or mockups
  • Be familiar with the Canvas API, D3, or similar.
  • Have used websockets in the client, and potentially a websocket library in the server
  • Have used Puppeteer or Selenium for automated E2E testing
  • Be comfortable with nginx or similar
  • Have used a client/server federated auth library eg. OAuth/OpenID, perhaps Kerberos
  • Be capable of creating simple backend applications in Node or Python, for testing or to proxy events


  • Flexible working options
  • Onsite gym, sauna, and fitness classes at no charge
  • Extensive medical benefits including an on-site doctor and therapist at no charge
  • Breakfast and lunch provided Tues, Weds and Thurs
  • Various supports for caregivers, including emergency dependent care
  • Beautiful Kings Cross office:
  • 25 days paid holiday per year + statutory holiday and paid sick days