Lead the Blazor front ends behind long-lived business systems

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Senior Blazor Developer · Bournemouth or remote, UK Lead the Blazor front ends behind long-lived business systems

We have built with Blazor since its first release and run it in production for insurance, travel, health and the trades, alongside our own products. This role leads that work on .NET 10 and ASP.NET Core: component architecture, performance, accessibility and the release engineering that keeps a front end safe to change every week for years.

How to apply Certification required Blazor Server, WebAssembly, Hybrid Blue-green releases on Azure 5+ years .NET, 2+ Blazor AZ-204 required Before you apply Open

Microsoft Certified: Azure Developer Associate Held and current on the day you apply.Exam AZ-204 · required

• Two paragraphs about you and your work
• Your CV, Word or PDF
• Proof of AZ-204: Microsoft Learn transcript or Credly badge link
• Email Sign in to view email

LocationBournemouth or remote, UK ContractContract, £300–£600 a day Experience5+ years .NET, 2+ years Blazor in production CertificationAZ-204 required on application The work

What you will work on

Blazor on .NET 10

Server, WebAssembly and .NET MAUI Blazor Hybrid applications with ASP.NET Core APIs behind them.

Performance and accessibility

Component libraries, state management, rendering performance, virtualisation and WCAG across large line-of-business screens.

Render modes, chosen deliberately

Static server rendering, streaming and interactive modes per page, not by default.

Release engineering

Blue-green slots on Azure App Service, regression suites that gate every swap, rollback in seconds.

Modernisation

Web Forms, MVC and WPF front ends moved onto Blazor release by release, without a big-bang rewrite.

Mentoring

Reviewing code across the team and raising the bar without raising your voice.

Microsoft Certified: Azure Developer Associate Exam AZ-204 · required for this role

Held and current on the day you apply. Every engineer applying for a role at Assemblysoft needs a current Microsoft Azure certification, and we verify it on Microsoft Learn or Credly before the first conversation. Include a link to your transcript or badge with your application.

• Microsoft Certified: DevOps Engineer Expert (AZ-400): Preferred; funded within your first year if not yet held.
• Microsoft Certified: Azure Solutions Architect Expert (AZ-305): Held and current on the day you apply, with its prerequisite AZ-104.

What we need from you

• A current Microsoft Certified: Azure Developer Associate (AZ-204), with proof included in your application.
• 5+ years of C# and ASP.NET, with at least 2 years of Blazor in production.
• Deep ASP.NET Core knowledge: middleware, authentication, minimal and controller APIs, SignalR.
• Azure App Service, Azure DevOps pipelines and infrastructure as code (Bicep or Terraform).
• Automated testing across unit, component (bUnit) and end-to-end (Playwright) levels.
• The judgement to say when a rewrite is not needed, and to explain why to a client.

Nice to have

• Microsoft Certified: DevOps Engineer Expert (AZ-400) or Azure Solutions Architect Expert (AZ-305).
• Oqtane or other modular Blazor frameworks; Telerik, Syncfusion or Radzen component suites.
• Experience bringing AI-generated codebases up to a production standard.

What we offer

In return

Certification funding

Exams, study time and annual renewals for the Microsoft credentials your role needs, and the next tier when you are ready for it.

Remote-first, UK

Work from home across the UK with a Bournemouth base to meet in; contract roles, full or part time.

Day rate

£300–£600 a day depending on role and experience, and a non-corporate team of senior engineers who review each other's work.

Systems that matter

Regulated, business-critical and long-lived: healthcare, insurance, transport, trades. Not throwaway builds.

How to apply for this role

Applications without proof of the required certification are not progressed, so please include it first time.

Apply for Senior Blazor Developer Azure certification, required for every role

Azure-certified engineers, verified before we talk

Every engineer applying for a role at Assemblysoft needs a current Microsoft Azure certification. You apply with proof of it, we verify it before the first conversation, and once you join we fund the exams, the study time and the annual renewals for the next tier.

Expert

Azure Solutions Architect Expert

Exam AZ-305. Required for our architect role and for anyone who signs off an Azure design.

DevOps Engineer Expert

Exam AZ-400. Preferred for engineers who own pipelines, environments and releases.

Associate

Azure Developer Associate

Exam AZ-204. The minimum for every developer role: ASP.NET Core and Blazor on Azure.

Azure Administrator Associate

Exam AZ-104. The prerequisite for the Solutions Architect Expert certification.

Fundamentals

Azure Fundamentals

Exam AZ-900. A useful start, but on its own it does not meet the requirement for any of our roles.

Badge artwork Microsoft Corporation, shown to identify the certifications required. Verify any credential on Microsoft Learn. Proof means a link to your Microsoft Learn transcript or your Credly badge; a PDF certificate is accepted if it carries a verification code.

Other roles

Also open

ASP.NET Core & Blazor Developer · AZ-204 required Azure Solutions Architect · AZ-305 required All roles