Principal Developer

  • Square One Resources
  • 03/02/2026
Full time Information Technology Telecommunications

Job Description

Job Title: Principal Developer
Location: London
Salary/Rate: £480-£530 a day
Start Date: Mid Feb
Job Type: Contract

Core Responsibilities
  • Help Define, document, and govern architecture, development, and data standards across engineering teams.
  • Design and evaluate architectural solutions, identifying risks, trade-offs, and alternative approaches.
  • Create Pocks and technical spikes to validate architecture decisions, technologies, and non-functional requirements.
  • Provide architectural design input across products within the Bankers Almanac portfolio.
  • Maintain accurate, up-to-date architecture artefacts and clearly communicate their implications to technical and non-technical stakeholders.
Engineering Excellence
  • Lead architectural reviews and provide actionable guidance to improve design quality and consistency.
  • Challenge assumptions and continuously evolve architecture patterns and operating models.
  • Act as a technical escalation point for complex engineering and architectural issues.
  • Promote sound engineering practices and contribute to a culture of technical excellence.
Collaboration & Stakeholder Engagement
  • Collaborate with senior architects, engineering leads, product owners, and business stakeholders to align designs and resolve cross-domain.
  • Serve as the primary technical point of contact for external technology partners, vendors, and suppliers.
  • Ensure architecture decisions support agreed SLAs, security, quality, cost, and delivery objectives.
Systems Reliability & Data Architecture
  • Assess and improve system health, performance, scalability, and resilience, proposing preventative and corrective actions.
  • Design and oversee complex data models, ensuring consistency, performance, governance, and regulatory compliance.
  • Contribute to the evolution of data architecture standards, modelling practices, and knowledge representation.
Required Experience
  • Experience in software engineering and/or solution architecture within enterprise environments.
  • Demonstrated experience operating at Senior or Principal level, providing architectural leadership across teams or systems.
  • Proven ability to design and deliver distributed, cloud-native, and data-intensive systems.
  • Strong background in data modelling and data architecture, across relational and non-relational technologies.
  • Experience identifying architectural risks, evaluating trade-offs, and guiding technical decision-making.
  • Experience working in high-availability or regulated environments (e.g., financial services) is highly desirable.
Education
  • Bachelor's degree in Computer Science, Software Engineering, or a related technical discipline, or equivalent practical experience.
  • Ongoing professional development and engagement with industry trends and emerging technologies.
Architecture & Engineering
  • Expert understanding of software architecture principles, patterns, views, and modelling techniques (logical, physical, deployment, data).
  • Strong experience with distributed systems design, including scalability, fault tolerance, resiliency, and eventual consistency.
  • Deep knowledge of modern software development practices including Agile, CI/CD, TDD, and trunk-based development.
  • Proven ability to lead architectural decision-making, assess trade-offs, and guide teams through complex technical challenges.
Programming & Frameworks
  • Expert-level proficiency in Java and Spring Boot, with strong experience building RESTful and event-driven services.
  • Strong working knowledge of Angular and Node.js for building modern web applications and APIs.
  • Experience across multiple programming paradigms, including object-oriented, functional, and event-driven approaches.
  • Strong command of Git and modern source control workflows.
Cloud, DevOps & Platform Engineering
  • Strong hands-on experience with AWS, including core infrastructure and cloud-native services.
  • PracticalexperiencewithDevOps practices, including:
    • CI/CD pipeline design and optimization Infrastructure as Code (e.g. Terraform, CloudFormation or equivalent)
    • Automated testing and deployment strategies
    • Environment management across development, test, and production
  • Experience working with containerization and orchestration technologies (e.g. Docker, Kubernetes or managed equivalents).
  • Exposure to observability and operational tooling, including logging, monitoring, tracing, and alerting.
  • Understanding of security-by-design, including identity, access management, and secure deployment practices.
Data & Systems
  • Expert-level knowledge of data modelling, design, and optimization, including schema evolution and performance tuning.
  • Strong experience with a variety of data storage and access technologies, such as:
    • Relational databases
    • Distributed and cloud-native data stores
    • Key/value, graph, and indexing-based systems
  • Understanding of data architecture concerns, including governance, standards, lineage, and data quality.
  • Experience designing systems that support high availability, disaster, and regulatory compliance.
Application & System Management
  • Experience with application lifecycle management, including deployment, monitoring, and operational support.
  • Ability to assess and improve system reliability, performance, and resilience in production environments.
  • Familiarity with incident management and root-cause analysis, contributing to preventative engineering improvements.
Professional Skills
  • Strong communication and presentation skills, with the ability to explain complex technical concepts clearly.
  • Proven ability to influence technical direction across teams and stakeholders.
  • Leadership mindset with a pragmatic, delivery-focused approach.