Overview

Pixexl is building the future of how people interact with the web—and we’re doing it faster than most people think is reasonable. We’re a fast-growing, self-funded SaaS platform with 4.8★ customer satisfaction and a 4.9★ team score, focused on building the next generation of website optimisation technology.

We’re hiring a Senior Software Engineer in London to help design and build planet-scale systems that power AI-driven website creation and optimisation. You’ll work on distributed backend services, agentic workflows, and large-scale infrastructure that directly shapes how real people experience the web.

This role is ideal for engineers who enjoy ownership, shipping quickly, and solving complex problems without unnecessary process.

Key Responsibilities

Platform & Systems Engineering

• Design and build distributed backend services that scale globally
• Develop and maintain high-performance systems running on Kubernetes
• Contribute to architecture decisions across core platform services

AI & Automation

• Build AI agents that orchestrate website creation and optimisation
• Develop human-simulator bots that browse, click, and behave like real users
• Work with LLMs, agentic workflows, and context-aware systems

Product-Focused Engineering

• Collaborate closely with product and design to ship meaningful improvements
• Take features from idea to production, owning outcomes end to end
• Continuously refine, refactor, and remove code that no longer delivers value

Quality, Performance & Reliability

• Ensure systems are observable, resilient, and performant at scale
• Write clean, maintainable code with a strong testing mindset
• Improve developer tooling and internal workflows

Required Skills & Experience

• 3+ years of experience building distributed backend systems
• Strong proficiency in TypeScript / JavaScript (Node.js)
• Experience designing APIs and backend services at scale
• Familiarity with cloud infrastructure, ideally AWS
• Experience working with Kubernetes and containerised systems
• Strong problem-solving skills and comfort working with ambiguity

Desired / Nice-to-Have Qualifications

• Experience with AI agents, LLMs, or agentic workflows
• Familiarity with vector databases and context engineering
• Experience with systems such as ClickHouse, MySQL, Redis, or Playwright
• Background in high-growth SaaS or developer-focused products

How We Work

• Core stack: TypeScript/Node, AWS, Kubernetes, ClickHouse, MySQL, Redis, Playwright
• AI tooling: Cursor, Codex, MCP, LLMs, agentic workflows
• Culture: ship often, own outcomes, debate ideas—not egos—and delete code that no longer serves the product

This Role Is a Great Fit If You

• Enjoy small teams, fast decisions, and high ownership
• Are comfortable shipping without perfect specs
• Value direct feedback and continuous improvement
• Prefer building and iterating over over-planning

Compensation & Benefits

• Competitive salary, based on experience
• Bonus or equity options depending on level

What’s in It for You

• Work on cutting-edge AI and web optimisation technology
• High impact role with real ownership over architecture and outcomes
• Join a highly rated, self-funded SaaS company with strong momentum
• Collaborate with experienced engineers who value speed and clarity

Perks

• Top-spec MacBook Pro
• Private health, dental, and vision insurance
• Monthly wellness allowance
• Pension contributions
• 20 days paid holiday plus UK public holidays (increasing with tenure)
• Flexible working hours, casual dress, team lunches, and regular outings