Should you hire .NET developers in-house or outsource the work? For London businesses the answer depends on how long you need the skills, how much control you want and your budget. This guide compares the real cost of hiring vs outsourcing .NET developers in London, with a worked example, so you can choose with confidence.
- Hire in-house when .NET is core to your product and you need people full time for years.
- Outsource when you need a project delivered, specialist skills, or flexible capacity without a long recruitment process.
- Combine both when you want a small in-house core with outsourced capacity for peaks and specialist work.
- Long-term product ownership
- Deep business knowledge
- Daily, close collaboration
- Fixed projects and deadlines
- Fast start and flexible team size
- Specialist or short-term skills
1. Your Options Explained
| Option | How it works | Best for |
|---|---|---|
| Permanent in-house hire | You employ .NET developers directly | Long-term product teams |
| Contractors | Individual developers on fixed-term contracts | Short-term gaps; check IR35 |
| Dedicated .NET development team | An outsourcing partner provides developers who work only on your product, usually for a monthly fee | Ongoing development without recruiting |
| Project outsourcing | A partner delivers an agreed scope, fixed price or time and materials | Defined projects with clear outcomes |
"Outsourcing" doesn't have to mean offshore. Outsourced .NET developers can be UK-based, offshore, or a blended team with UK-hours project management.
2. The Cost of Hiring .NET Developers in London
Salary is only the starting point. According to ITJobsWatch, the median advertised salary for .NET developer roles in London was £77,500 in the six months to January 2026, with the 25th percentile at £60,000 and the 75th percentile at £93,750 (ITJobsWatch). These are advertised salaries, so actual offers vary by seniority and skills.
Costs on top of salary
- Employer National Insurance: 15% on earnings above the secondary threshold of £5,000 a year (GOV.UK).
- Pension: at least 3% employer contribution on qualifying earnings under auto-enrolment (GOV.UK).
- Recruitment: agency fees are usually a percentage of first-year salary, plus your team's time interviewing.
- Equipment, software and licences: laptop, Visual Studio or JetBrains licences, Azure and tooling.
- Benefits, training and management time.
- Time to hire: weeks or months before a new developer is productive.
3. The Cost of Outsourcing .NET Development
Outsourcing costs depend on where the team is based, seniority and the engagement model. As a reference, our own published rates for hiring .NET developers are around £60 to £120 an hour for UK-based developers and £25 to £50 an hour for a blended team with UK-hours management and offshore developers.
With outsourcing, the rate usually includes recruitment, equipment, employment costs and replacement cover. You pay for the time or scope you agree, and can scale the team up or down.
4. Worked Cost Comparison: One Mid-Level .NET Developer for a Year
This illustrative example uses the London median advertised salary. Your figures will differ.
| In-house cost item | Annual cost |
|---|---|
| Salary (London median advertised) | £77,500 |
| Employer NI: 15% of (£77,500 − £5,000) | £10,875 |
| Pension: 3% of qualifying earnings (£6,240 to £50,270) | £1,321 |
| Core employment cost | £89,696 |
Add recruitment fees, equipment, licences, benefits and management time, and the true first-year cost is higher still.
| Outsourced option (about 140 billable hours a month) | Annual cost |
|---|---|
| UK-based developer at £60 an hour | £100,800 |
| Blended team developer at £35 an hour | £58,800 |
Illustrative only, excluding VAT. Rates from our hire .NET developers page; hours and rates vary by engagement.
What this shows
- For a full-time, long-term role, a UK-based outsourced developer can cost more than an employee once you compare core costs alone.
- A blended team is often cheaper than hiring in London, with UK-hours coordination.
- For short projects or part-time needs, outsourcing usually wins, because you only pay for the time you use and avoid recruitment and notice periods.
Tell us what you're building and for how long. We'll compare hiring, outsourcing and a hybrid model, and send an itemised GBP estimate.
Get my free estimate5. In-House vs Outsourced .NET Developers: Side by Side
| Factor | In-house | Outsourced |
|---|---|---|
| Time to start | Weeks to months of recruitment | Often 1 to 2 weeks |
| Cost structure | Fixed salary plus employment costs | Pay for agreed time or scope |
| Flexibility | Hard to scale up or down quickly | Scale with notice in the contract |
| Skills range | Limited to the people you hire | Access to wider .NET, Azure and DevOps skills |
| Business knowledge | Builds deep knowledge over time | Needs good onboarding and documentation |
| Control | Direct day-to-day management | Managed through agreed processes and reporting |
| Continuity risk | Notice periods and resignations | Partner covers absences and replacements |
| Admin | Payroll, HR, equipment, training | One contract and invoice |
6. When to Hire .NET Developers In-House
- .NET software is your core product and competitive advantage
- You need developers full time for several years
- Your work depends on deep, constant contact with business teams
- You have engineering leadership to recruit, manage and develop people
- You handle data or systems you prefer to keep fully within your own staff
7. When to Outsource .NET Development
- You have a defined project, such as a new portal, API or integration
- You need to start quickly and can't wait for recruitment
- You need specialist skills, such as migrating from .NET Framework, Azure or DevOps
- Your workload goes up and down
- You don't have in-house technical leadership yet
Modernising an older .NET application? See our legacy app modernisation services. Building something new? See our .NET development services.
8. The Hybrid Option: In-House Core, Outsourced Capacity
Many London businesses don't choose one or the other. A common model is a small in-house team that owns the product and architecture, supported by a dedicated .NET development team from a partner for extra capacity, specialist work or deadlines.
- Keeps knowledge in-house through your own lead developer or architect.
- Adds capacity quickly without permanent headcount.
- Reduces risk if someone leaves or is unavailable.
Learn more about dedicated developers and co-development.
9. Risks of Each Option and How to Manage Them
| Risk | How to manage it |
|---|---|
| In-house: slow or failed hires | Use clear role specs and practical assessments; plan for cover while recruiting |
| In-house: key-person dependency | Document systems and share knowledge across the team |
| Outsourced: communication gaps | Agree a named contact, UK-hours overlap and regular demos |
| Outsourced: quality concerns | Ask for relevant .NET work, code reviews and automated tests |
| Outsourced: lock-in | Make sure you own the code and repositories from day one |
| Contractors: IR35 | Check the off-payroll working rules (GOV.UK) or engage through a company under a service contract |
10. How to Decide: Five Questions
- How long do you need .NET skills? Months suggests outsourcing; years suggests hiring.
- How defined is the work? A clear scope suits project outsourcing.
- Who will lead the technical work? Without a technical lead, outsourcing to a managed team is safer.
- How fast do you need to start? Recruitment takes time; outsourcing can start in weeks.
- What's your total budget, not just salary? Compare full employment costs with outsourced rates.
Choosing a partner? Read our guide on how to choose a software development company in the UK, and compare broader costs in our software development cost guide.
11. Frequently Asked Questions
Is it cheaper to hire or outsource .NET developers in London?
It depends on how long you need them. For a full-time role over several years, hiring can cost less than a UK-based outsourced developer once you compare core employment costs. For projects, part-time needs or short-term capacity, outsourcing is usually cheaper because you avoid recruitment, employment costs and idle time. A blended outsourced team is often cheaper than hiring in London.
How much does it cost to hire a .NET developer in London?
ITJobsWatch reported a median advertised salary of £77,500 for .NET developer roles in London in the six months to January 2026. On top of salary, employers pay National Insurance at 15% above the £5,000 threshold, at least 3% pension on qualifying earnings, and recruitment, equipment, training and management costs.
How much does outsourcing .NET development cost?
It depends on location, seniority and engagement model. Our published rates are around £60 to £120 an hour for UK-based .NET developers and £25 to £50 an hour for a blended team with UK-hours management. Projects can also be quoted at a fixed price after discovery. Prices exclude VAT.
What is a dedicated .NET development team?
A dedicated .NET development team is a group of developers provided by an outsourcing partner who work only on your product, usually for a monthly fee. You set priorities while the partner handles recruitment, employment and replacement cover.
How quickly can outsourced .NET developers start?
Outsourced developers can often start within 1 to 2 weeks of approving profiles, compared with weeks or months for permanent recruitment.
Can I combine in-house and outsourced .NET developers?
Yes. Many businesses keep a small in-house team that owns the product and architecture, and add outsourced developers for extra capacity, specialist skills or deadlines.
Sources
- ITJobsWatch: .NET Developer jobs in London (salary data, six months to January 2026)
- GOV.UK: Rates and thresholds for employers 2025 to 2026
- GOV.UK: Workplace pensions, what you, your employer and the government pay
- GOV.UK: Understanding off-payroll working (IR35)
Book a free consultation. We'll look at your project, timeline and budget, and tell you honestly whether hiring, outsourcing or a hybrid model makes most sense.
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