Skip to main content
CornerwaysSoftware

Jonathan LevySenior / Principal Backend & Systems Engineer · UK · LinkedIn

Senior .NET and Azure engineering for business-critical systems

Around 20 years designing, building and modernising business-critical software across financial services, payments, SaaS and regulated environments. You work directly with the engineer: hands-on delivery, architecture and technical leadership, with agentic, AI-assisted delivery under human ownership of quality.

Open to discussing suitable contract engagements, UK remote or hybrid.

Discuss an engagementSee how I can help
Core stack
C#/.NET, Azure, APIs, data and distributed backend systems
AI-assisted engineering
Claude Code, Codex, Copilot and Cursor, with review and guardrails
Sectors
FinTech, payments, SaaS and regulated environments
Leadership
Former founder and Head of Engineering

Engagements

Ways to work together

Most work starts as a contract engagement or a defined piece of technical work. Ongoing stewardship usually follows once I know the system well.

Primary

Contract engineering

Senior hands-on engineering inside your team, on new development or on systems that already carry the business.

  • Senior C# and .NET engineering, including full-stack business applications
  • Azure-based systems, APIs and systems integration
  • SQL Server and PostgreSQL data design and performance
  • Developing, stabilising and modernising existing and legacy systems
  • Architecture and technical decision-making within the team
  • Technical leadership alongside delivery
  • Agentic, AI-assisted delivery with human ownership of quality
  • Delivery in complex or regulated environments

Suited to: UK companies and consultancies that need experienced .NET or Azure contract capacity. Remote, or hybrid where it makes sense.

Discuss a contract requirement

Defined problem

Architecture and engineering interventions

Focused senior attention on a specific technical problem, without adding a permanent developer.

  • Architecture assessment and modernisation planning
  • Technical discovery before a significant development investment
  • Integration planning across systems and suppliers
  • Investigating reliability, maintainability or delivery problems
  • Assessing an inherited or poorly understood codebase
  • Recovery planning for a troubled software initiative

Suited to: CTOs, engineering leaders and founders who need an experienced, independent view and a practical plan.

The output is engineering judgement and a written recommendation. It is not a formal audit, certification or security accreditation.

Tell me about the system

Ongoing

Software stewardship

Continuing ownership of an important existing system, with reserved engineering time each month.

  • An agreed number of reserved engineering hours
  • Planned maintenance, dependency and platform updates
  • Deployment oversight and small improvements
  • Technical review, documentation and advice when decisions arise
  • A defined response time for non-urgent requests

Suited to: Organisations whose system I already understand, usually after a contract or intervention.

Scoped individually. This is planned engineering capacity, not hosting, 24-hour support or emergency cover.

Ask about stewardship

Capabilities

Experience and capabilities

Deep foundations in C#/.NET, Azure and distributed backend systems, with hands-on AI-assisted engineering and AI-enabled products on top.

Engineering

  • C# and .NET, including ASP.NET Core and Entity Framework
  • Full-stack business applications with Angular, React and TypeScript
  • APIs and systems integration
  • SQL Server and PostgreSQL
  • Legacy system development and modernisation
  • Automated testing: TDD, xUnit and Playwright

Cloud and architecture

  • Microsoft Azure: App Service, Functions, Service Bus, Azure SQL, Cosmos DB and Application Insights
  • Software and solution architecture
  • Cloud systems, integrations and automation
  • Bicep, Docker, Azure DevOps and GitHub Actions pipelines

AI and agentic engineering

  • Agentic development with AI coding agents across the whole delivery cycle
  • Implementation and reviewer-agent workflows, including adversarial PR review
  • Guardrails for AI-generated code: tests, review and human ownership of decisions
  • Prompt and agent engineering, and MCP-connected workflows
  • Multi-stage LLM workflows with structured, schema-validated outputs
  • Human-in-the-loop trust boundaries and deterministic safeguards
  • Retrieval with Azure AI Search, embeddings and vector search
  • Document processing and PII redaction with Azure Document Intelligence

Leadership and domains

  • Technical leadership and engineering management
  • Running software delivery and working with business stakeholders
  • Fintech, payments, SaaS and financial services
  • Regulated industries
  • Business applications and business automation

Experience

Recent experience

The four most recent roles, newest first.

  1. Jul 2026 – present

    Long-lived .NET platform with financially sensitive calculations

    Senior Software Engineer

    • Working on a large, long-lived .NET platform with financially sensitive calculations and business workflows, combining legacy modernisation, new functionality and regression protection
    • Working agentically with Claude Code and Codex as primary coding agents, using implementation and reviewer-agent workflows, adversarial review and guardrails around AI-generated code, while retaining ownership of architecture, technical decisions, risk, validation and acceptance
    • Delivering substantial new financial-calculation functionality across backend services, database changes, UI and automated tests, while strengthening regression coverage and shortening the test feedback loop
    • .NET
    • EF6
    • SQL
    • Angular
    • Playwright
    • Claude Code
    • Codex
    • Bicep
    • Docker
    • Azure DevOps

  2. Jan–May 2025, Aug 2025, Mar–Apr 2026

    Regulated warehouse and ordering platform

    Backend Engineer · Contract, three engagements

    • Completed three separate engagements, returning to support ongoing development and production go-live. Built C# / ASP.NET Core backend services for pharmaceutical ordering, storage, dispatch and inventory workflows in a regulated environment
    • Supported production go-live of the warehouse-management platform and delivered invoice-processing functionality using .NET Core, Playwright, SendGrid and QuestPDF. Applied TDD and xUnit across API and application development
    • C#
    • ASP.NET Core
    • EF Core
    • Playwright
    • SendGrid
    • QuestPDF
    • TDD
    • xUnit

  3. Aug 2024 – Dec 2024

    Card payments and telecoms provisioning

    Backend Engineer · Contract

    • Built .NET Core services for a remote card-payment platform supporting phone and payment-link transactions, integrating Opayo, Worldpay and Barclays Payment Services
    • Also built a TypeScript / Node.js telecoms-provisioning service processing bulk CSV/XLSX data from Azure Blob Storage, with validation, account and service mapping, asynchronous provisioning via Azure Service Bus and persistence to PostgreSQL
    • Worked across Azure Functions, Redis and SignalR, with retries, telemetry, logging and failure handling built into the workflow
    • .NET Core
    • TypeScript
    • Node.js
    • Azure Functions
    • Service Bus
    • PostgreSQL
    • Redis
    • SignalR

  4. Mar 2024 – Jul 2024

    Conversational document search and redaction on Azure AI

    Lead Application Developer · Contract

    • Designed and delivered an enterprise document-search and conversational platform using .NET and Azure AI services. Built SharePoint ingestion workflows using Azure Logic Apps and Azure Storage and implemented embeddings / vector retrieval across tens of thousands of internal documents using Azure AI Search
    • Built the application using .NET APIs, SignalR and Cosmos DB-backed conversation history. Also delivered an automated PII-redaction system using Azure Document Intelligence, together with Angular / .NET user management, permissions and document-level access control. Both solutions progressed through client UAT
    • .NET
    • Azure AI Search
    • Embeddings
    • Document Intelligence
    • Logic Apps
    • Cosmos DB
    • SignalR
    • Angular

See the full career history

Built by Cornerways

RL Engineering

Website and quotation-workflow revamp for a South Wales precision-engineering company

Revamped an established WordPress website for an external client, restructuring it around the company's CNC machining capabilities, quality credentials and real manufactured work.

  • Reworked the content and enquiry journey, expanded the project portfolio with real production work and introduced clearer calls to action
  • Upgraded the quotation form so customers can submit drawings, CAD models and supporting documents, with file validation and spam protection
  • Improved technical SEO, analytics and English/Welsh navigation, delivered incrementally against the live site rather than as a rebuild
  • WordPress
  • Theme customisation
  • JavaScript
  • CSS
  • Gravity Forms
  • Secure file uploads
  • Technical SEO
  • Multilingual content

Visit rl-engineering.co.uk

Accrue

Options trade tracking and UK tax reporting, launched in 2025

A subscription product Cornerways designed, built and ran for UK investors, covering trade workflows, reporting and tax-aware exports.

  • .NET REST API, React and TypeScript, PostgreSQL and a Next.js marketing site
  • UK tax rules such as Section 104 pooling and the 30-day rule
  • Authentication with ASP.NET Identity, subscription billing with Stripe, hosted on Azure with Bicep
  • .NET
  • React
  • TypeScript
  • Next.js
  • PostgreSQL
  • ASP.NET Identity
  • Stripe
  • Azure
  • Bicep
Accrue home page, showing the product summary and a dashboard preview

CareerOS

AI-enabled work evidence recorder, in development since Jul 2026

A local-first system for recording the work I do, because the detail of what was built, decided and delivered is easy to forget. Raw notes, documents and existing CVs become structured, human-approved facts, each linked back to its source.

  • Staged LLM workflow that extracts and organises work evidence, with structured, schema-validated outputs
  • Explicit human-in-the-loop trust boundaries, provenance on every fact and adversarial claim verification, so unverified AI output is never silently promoted
  • Durable, restartable orchestration with SQLite-backed stage state, retries and immutable artefacts, covered by 115 automated tests
  • .NET 10
  • ASP.NET Core
  • EF Core
  • SQLite
  • GitHub Copilot SDK
  • OpenAI SDK
  • Structured outputs
  • xUnit

About

Working directly with a senior engineer

Cornerways Software Ltd is my contracting company. When you engage Cornerways, you work with me directly. There is no account manager and no delivery team behind the scenes: the person you speak to is the person doing the work.

I'm a senior / principal backend and systems engineer with around 20 years' experience designing, building and modernising business-critical software across financial services, payments, SaaS and regulated environments. My foundation is C#/.NET, Azure, APIs, data, integration and distributed backend systems, and my experience spans hands-on engineering, architecture, technical leadership, engineering management and end-to-end product ownership.

I particularly enjoy building and evolving complete systems: taking a business problem from requirements and architecture through backend services, integrations, data, testing, deployment and operation. I've built products from scratch, modernised long-lived platforms and worked across financially sensitive systems where reliability, correctness and commercial judgement matter.

My current focus is AI-assisted engineering: working agentically while keeping ownership of architecture, risk and acceptance, and building AI-enabled software such as enterprise search on Azure AI and CareerOS. The experience section has the detail.

As a former founder and Head of Engineering, I'm most effective where I can combine hands-on engineering with architecture, product thinking and responsibility for getting useful software into users' hands.

Process

How an engagement begins

Engagements are scoped and priced according to the work and the engagement model. There are no packaged prices.

  1. An initial conversation

    Send a short message about the role, project or system. If it looks like a fit, we arrange a call. There is no obligation.

  2. Agree the shape of the work

    For contracts: scope, duration, working arrangements and IR35 status. For defined work: the question to answer, what you receive and the timescale.

  3. Terms in writing

    Contract work is usually on a day rate. Interventions are usually a fixed or capped fee. Stewardship is a monthly arrangement agreed in advance.

  4. Work begins

    Regular, direct communication, with progress, risks and decisions made visible as the work goes.

Contact

Start a conversation

Tell me about the role, project or system. A few lines is enough to start. I read every enquiry and reply by email.

Prefer email? Write to jon@cornerways.software.