Staff Software Engineer in London

When you join G2, you’re joining the team that helps businesses reach their peak potential by powering decisions and strategies with trusted insights from real software users. G2 is the world’s largest and most trusted software marketplace. More than 100 million people annually — including employees at all Fortune 500 companies — use G2 to make smarter software decisions based on authentic peer reviews.

As we continue on our growth journey, we are striving to be the most trusted data source in the age of AI for informing software buying decisions and go‑to‑market strategies.

At G2, we have big goals but we stay grounded in our PEAK (P + E + A + K) values. You’ll be part of a value‑driven, growing global community that climbs PEAKs together. We cheer for each other’s successes, learn from our mistakes, and support and lean on one another during challenging times. With ambition and entrepreneurial spirit we push each other to take on challenging work, which will help us all to grow and learn.

You will be part of a global, diverse team of smart, dedicated, and kind individuals—each with unique talents, aspirations, and life experiences. At the heart of our community and culture are our people‑led ERGs, which celebrate and highlight the diverse identities of our global team. As an organization, we are intentional about our DEI and philanthropic work (like our G2 Gives program) because it encourages us all to be better people.

G2 is looking for a Staff Software Engineer specializing in AI/Generative technologies. You will be a hands‑on technical leader building sophisticated AI‑powered features within our product suite. This role suits an engineer who views AI as a powerful collaborator and is ready to drive high‑impact generative AI initiatives. You will implement AI‑first solutions, develop prompt‑engineering best practices, and mentor team members on AI‑augmented development.

In This Role, You Will:

• Build AI‑first features: Design and implement intelligent features from concept to production within our Ruby on Rails/Python platform. Drive technical decisions for your projects and ensure solutions are scalable, maintainable, and aligned with product requirements.
• Develop prompt‑engineering solutions: Create, test, and refine prompts for production use cases including data synthesis, content generation, and workflow automation. Build automated prompt‑testing frameworks and measure model performance to optimize results.
• Champion AI‑augmented development: Serve as the go‑to expert on AI coding assistants within your team. Demonstrate best practices for integrating tools like GitHub Copilot and Claude Code into daily workflows, and help teammates increase their productivity through effective AI collaboration.
• Implement AI integrations: Evaluate and integrate third‑party and open‑source AI models into our backend (Ruby on Rails/Python) and frontend (JavaScript, Hotwire, React) systems. Build reliable, production‑grade implementations that solve real customer problems using LLM APIs.
• Build agentic architectures: Design and implement agent‑based patterns that effectively combine LLM autonomy with human oversight, tool use, and multi‑step reasoning workflows.
• Enable AI with quality data: Build data pipelines and ensure data quality for AI‑driven features. Apply expert‑level SQL and PostgreSQL skills to support model training, fine‑tuning, and inference.
• Collaborate on AI initiatives: Work closely with product managers, designers, and data scientists to deliver AI‑powered features. Provide technical input on feasibility, effort, and approach for AI projects on your team.
• Ensure quality and reliability: Implement comprehensive testing strategies (unit, integration, functional) for AI features. Champion code quality, performance optimization, and operational reliability in production.
• Mentor team members: Guide other engineers on your team in AI technologies and best practices. Share knowledge through code reviews, pair programming, and technical discussions.

Minimum Qualifications:

• 8 to 10 years of professional programming experience in web application environments.
• Expert‑level proficiency in Ruby on Rails and/or Python; strong working knowledge of modern JavaScript frameworks.
• Hands‑on experience building agentic AI systems and implementing multi‑step reasoning patterns with LLMs.
• Direct experience working with LLM APIs from providers such as OpenAI, Anthropic, or Google, including prompt engineering and response handling.
• Regular use of AI coding assistants (e.g., GitHub Copilot, Claude Code) as part of your daily development workflow.
• Solid understanding of the generative AI landscape, including strengths and limitations of major models.
• Experience with agile development practices including CI/CD, code reviews, and feature flags.
• Bachelor’s degree in Computer Science or related field; advanced degree preferred.

What Can Help Your Application Stand Out:

• Experience with AI frameworks such as Langchain, LlamaIndex, Ollama, FastMCP, or similar agent orchestration tools.
• Experience fine‑tuning or deploying open‑source models for specific use cases.
• Contributions to open‑source AI/ML projects or relevant publications.
• Advanced PostgreSQL skills including performance tuning and query optimization.
• Experience with Hotwire and Tailwind CSS within a design system.

At G2, we are committed to creating an inclusive and diverse environment where people of every background can thrive and feel welcome. We consider applicants without regard to race, color, creed, religion, national origin, genetic information, gender identity or expression, sexual orientation, pregnancy, age, or marital or veteran or physical or mental disability status.

G2 incorporates AI‑powered technology to enhance our candidate evaluation process. These tools may assist with initial application screening, skills assessment analysis, and identifying candidates whose qualifications align with specific role requirements. While AI technology supports our recruitment workflow, all final hiring decisions remain under human oversight and judgment.