Senior Python Developer

Tech4 Ltd; City Of London; Hybrid; GBP 90,000 - 130,000; Full time

Job summary

Tech4 Ltd in London embraces AI-native development to evolve its platform. You will be a hands‑on Senior Python Developer guiding technical direction while mentoring engineers and collaborating with Product and Design from discovery through production.

Responsibilities include architecting scalable cloud services, enforcing secure AI outputs, and driving reliability and performance. Hybrid London-based role with strong growth potential.

Qualifications

• Hands-on senior engineer with product mindset and strong AI awareness.
• Experience leading or mentoring teams and shaping technical direction.
• Proven ability to design scalable, secure cloud systems.

Responsibilities

• Architect and implement scalable cloud-based services using AI-native workflows.
• Lead feature delivery, coordinating with Product and Design teams.
• Define guardrails for AI-generated code with security and cost controls.
• Improve platform reliability, performance, and user experience via observability.
• Shape architecture for AI tooling, LLM integrations and human-in-the-loop controls.

Skills

Python

React

Azure

GCP

Tools

GitHub Actions

GitLab CI

Docker

Datadog

Grafana

Job description

Senior Python Developer - PYTHON / REACT / AZURE / GCP - is required by fast growing and highly successful international organisation.

They are seeking an experienced Senior Python Developer to help evolve and extend their platform while guiding technical direction and supporting team development. This role centres on solving real‑world problems and making thoughtful technical decisions that balance business impact with engineering trade‑offs. You will work closely with Product Managers, Designers, and engineers to take ideas from inception through to production, ensuring they build the right solutions for their customers. You will act as both a senior technical contributor and a product‑minded engineer, someone who doesn’t just implement requirements but actively shapes them. You will challenge assumptions, ask the right questions, and help ensure we are solving meaningful problems in the most effective way. You will contribute to technical strategy by identifying opportunities to improve system reliability, performance, and user experience within our current architecture, while also supporting the evolution of their strategic platform. This role will play a key part in driving the adoption of AI across engineering, leveraging emerging technologies and embedding AI‑native workflows to improve how they design, build, and deliver software.

This role is predominantly hands‑on, with around 20–30% of time on technical leadership: architecture, mentoring, and shaping how the team works.

Key Responsibilities

• Help the team move faster by adopting AI‑native workflows and the shift to an agentic development lifecycle, without compromising the architectural qualities that make their platform reliable, scalable, and maintainable over the long term.
• Define guardrails, review practices, and validation gates that hold AI‑generated code to our standards for security, reliability, and cost‑efficiency (FinOps). These are first‑class concerns in agentic pipelines, not afterthoughts.
• Design, build, and operate software across our platform, applying the same rigour to AI‑augmented work as to anything else you ship.
• Embed deeply with Product and Design from the earliest stages of discovery, using rapid prototyping and iteration to compress the gap between idea and validated solution.
• Act as feature lead on a rotating basis, taking accountability for the development and delivery of a feature from shaping through to production. This means partnering with Product and Design on the approach, breaking the work down, coordinating the engineers contributing to it, removing blockers, and being the person who knows the state of the feature at any point.
• Shape platform architecture with an architectural lens, contributing to long‑term decisions about how AI tooling, LLM integrations, and human‑in‑the‑loop controls evolve across the stack.
• Continuously identify and exploit opportunities to improve performance, reliability, and user experience, using observability and analysis to find signals in noisy systems.
• Navigate confidently across legacy and greenfield contexts, applying AI tooling pragmatically to modernise where it matters most.
• Set the engineering standard, demonstrating through your own work what excellent looks like when much of the code is AI‑generated.
• Grow the team's capability and confidence with AI‑native practices, coaching more junior engineers to think critically about model outputs, prompt design, and the boundaries of automation.
• Define and evolve best practices for code quality, testing, documentation, and delivery in a world where much of the first draft is AI‑generated.
• Evolve CI/CD pipelines to incorporate agentic workflows, automated testing, AI‑assisted code review, and intelligent deployment gates.

About you

You’re a hands‑on senior engineer with a product mindset and the judgement to know which trade‑offs matter. You care about business impact as much as engineering quality, and you’ve been building with AI tools long enough to know how to use them effectively.

You’ll likely bring:

• Deep experience building scalable, secure, cloud‑based systems, giving you the foundation to confidently guide and validate agentic workflow outputs.
• Proven ability to work across both legacy and greenfield codebases, using modern tooling to improve reliability and evolve architecture pragmatically.
• Strong system design fundamentals across scalability, performance, and distributed systems, including API design (REST, GraphQL).
• Hands‑on experience with observability tooling (Datadog, Grafana, or similar) and a data‑informed approach to system health and reliability.
• Solid SQL and data management skills, with an appreciation for AI‑enabled, data‑driven systems.
• Familiarity with CI/CD, containerisation (GitHub Actions, GitLab CI, Docker), and DevSecOps practices in modern AI development environments.
• A pragmatic approach to testing, knowing what to cover, what to skip, and how to use AI to improve efficiency.
• Experience mentoring engineers and supporting the adoption of modern tools and AI‑native workflows.
• Strong communication skills and the ability to articulate technical decisions and trade‑offs clearly.

You’ll stand out if you:

• Ask "what problem are we solving and why?" before reaching for a solution.
• Act as a genuine partner to Product and Design, shaping the problem, not just delivering against a spec.
• Balance technical debt and feature delivery with long‑term business value in mind.
• Make confident decisions with incomplete information and thrive in fast‑moving, evolving environments.
• Bring curiosity and hands‑on experience with agentic workflows, using them to raise the bar for engineering.

Excellent training and career development opportunities exist for the role right candidate.

Basic salary £(phone number removed) + excellent benefits

Based London / hybrid