.NET Developers in the UK

About .NET Developers

Senior C# engineers for ASP.NET Core APIs, Blazor front ends, Entity Framework data layers, and Azure workloads, available as a dedicated developer or a small product team. This is a newer service line for us, so we will be honest about where our shipped experience is deepest and back every .NET build with written scope, tests, and CI. Flat INR quotes, W-8BEN and LUT on file, and a reply within 24 hours.

What the engagement includes

• Senior engineers only, no interns, and one named owner for the whole engagement.
• Modern .NET by default: .NET 8 or the current LTS .NET 10, ASP.NET Core, and EF Core, not a fresh WebForms project.
• Tests and CI are part of the build, not a later cleanup: xUnit or NUnit, integration tests, and a green pipeline before merge.
• You own the GitHub or Azure DevOps repo, the cloud accounts, and the IP from day one, with full transfer on payment.
• Flat INR quotes with GST for Indian clients, and USD, GBP, CAD, or AED via Wise for overseas teams, with W-8BEN and LUT on file.
• A 24-hour response including weekends, and a paid trial sprint on request so you can judge the work before a longer commitment.

Visitor rules, the Service Supplier route the India deal opened, and National Insurance for on-site .NET work

.NET estates in the UK still run on servers in a client's own building more often than most stacks do, IIS farms, SQL Server clusters and Active Directory joined to everything, and that brings requests a remote team rarely gets: come and sit with us for the cut-over weekend, or walk the server room before the migration plan is signed. Indian nationals need a visit visa before travelling, and what a visitor may do here is set by Appendix Visitor: Permitted Activities, which draws its lines more tightly than buyers expect. A business visitor may attend meetings, carry out site visits and inspections, and be briefed on a UK customer's requirements, but the rule adds that any work for the customer is done outside the UK. The intra-corporate provisions do not rescue a supplier in our position: an overseas employee may advise and work with clients only where the project is delivered by the UK branch of the employer, and not where it is delivered directly to the UK client by the employer overseas. The provision that does fit some .NET work is the one written for suppliers. An employee of an overseas company may install, dismantle, repair, service or advise on computer software or hardware, or train UK staff to do so, where there is a contract of purchase, supply or lease with a UK organisation and the overseas company is the supplier, or where after-sales service was agreed at the time of the sale. So a discovery visit to map the estate, and deploying and configuring software we supplied onto your Windows servers under that contract, can sit within the rules, while writing new features at a desk in your office does not. The practical consequence is planning. Every on-site day is listed in advance with its purpose, the invitation letter describes those activities and nothing broader, and development stays in India. Which activities a particular visit covers is for an immigration adviser to confirm.

For longer stints the route changed this summer. The UK-India Comprehensive Economic and Trade Agreement entered into force on 15 July 2026, and the Home Office's table of sectors for the Service Supplier visa, updated on 1 September 2026, now marks computer-related services as covered for India, both for employees of an overseas service provider and for independent professionals, where the general WTO commitment column leaves that sector blank. The government's explainer says contractual service suppliers under the agreement can come for up to 12 months. It is a sponsored route, and the sponsor is the UK business receiving the service. Under the Immigration Rules the sponsor needs a licence, must be A-rated, and must hold a contract with the overseas service provider that is registered with the Home Office and covered by a trade agreement in force; the certificate of sponsorship names that contract. The engineer needs at least 12 months working for the employer outside the UK, a degree or equivalent technical qualification, and a job in an eligible occupation code. Two refusal grounds shape how the engagement is written. The job must not amount to hiring the worker out to fill a position with a third party, or routine ongoing work for someone other than the sponsor, and the rules require the job to comply with the National Minimum Wage and Working Time Regulations. A defined piece of on-site work, such as moving an on-premises estate from .NET Framework onto current .NET with its databases and identity integration, is described in the contract as a deliverable with an end date, while the remote team carries on around it. The sponsor licence is the long pole, so a client expecting to need engineers on site for months starts that application well before the work is due, rather than after the plan is approved. Whether your organisation should sponsor, and under which code, is for an immigration adviser.

National Insurance changed on the same day. The UK and India's Double Contributions Convention came into force on 15 July 2026, and HMRC's guidance says employees sent to work temporarily in the UK by their Indian employer on or after that date stay under Indian social security if their UK work is not expected to exceed 60 months. Neither they nor their employer pay UK contributions, and the evidence is a certificate of coverage from India's Employees' Provident Fund Organisation. The transition caught people mid-visit. Anyone already working here for an Indian employer immediately before 15 July 2026, part way through the 52 week exemption that applied before the Convention, is not treated as a detached worker under it, and has been liable to UK contributions from that date. HMRC also points UK businesses that have employees of an Indian employer working for them, which it calls host employers, to its further guide to PAYE and National Insurance, CWG2, to check whether they have obligations of their own, secondary contributions included. That makes the certificate a document you will want to see rather than one we simply hold. So for any engineer travelling to work on site, whether a fortnight for a SQL Server cut-over or a Service Supplier assignment of several months, the certificate of coverage should be applied for before departure, a copy sent to you with the travel dates, and the days actually spent in the UK logged, because the expected length of the posting is what the Convention measures and the record is what shows it was right. Income tax is a separate question with separate rules, and the two are not settled by the same document. How the Convention and CWG2 apply to your own payroll is for your accountant.

How we work with UK clients

UK engagements tend to start with procurement questions rather than technical ones. Who holds the data, which law governs the contract, whether you can produce a record of processing if the ICO asks. We answer those in the proposal instead of leaving them to a legal review three weeks in, because that review is where UK projects usually stall.

Invoicing is the other thing worth settling early. We are outside the UK, so services we supply generally fall under the reverse charge and your finance team accounts for the VAT rather than paying it to us. Our invoices say so explicitly. We quote in pounds, the figure does not move with the exchange rate mid-project, and payment by bank transfer avoids the card fees that make a five-figure invoice unnecessarily expensive.

Questions UK clients ask

.NET Developers: common questions

Other markets we work in