Hiring a developer in the UK means navigating IR35 before your first contract is signed. Get this wrong, and your business faces back taxes, penalties, and supply chain liability.
What "IR35-compliant hiring" means
IR35 compliance is not a certification. It is a set of documented processes. Medium- to large-end clients are responsible for determining their contractors' IR35 compliance and justifying that decision in a Status Determination Statement (SDS).
There are different rules for those working for a small business versus mid or large-sized businesses. Small businesses in the private sector are exempt from the reform, leaving contractors to make their own decisions. From April 2025, a medium- to large business is defined as having over 50 employees, annual turnover above £15 million, or a balance sheet above £7.5 million.
Four hiring models — and where the risk sits
Model | Who issues SDS | Who runs PAYE | Best for |
|---|---|---|---|
Recruitment agency + umbrella | Client | Umbrella company | Inside IR35 roles, scale hiring |
Direct PAYE via platform | Client | Platform/payroll | Predictable, long-term engagements |
Statement of work (SoW) | Client | Consultancy | Deliverable-based projects |
Vetted talent marketplace | Determined per engagement | Platform-assisted | Fast, compliant contractor matching |
When a contractor is classed as inside IR35, the two options are direct PAYE employment with the end client, or processing through a compliant umbrella company that handles all required deductions at source.
What no platform can promise
No platform guarantees an outside-IR35 outcome. IR35 status depends on actual working practices — control, substitution, and mutuality of obligation, not on how the contract is labeled. HMRC assesses the reality of each engagement, not the documentation alone.
Double taxation occurs when HMRC retroactively deems a contractor inside IR35 after the client had classified them as outside IR35; HMRC then issues a tax bill to the fee-paying party without offsetting the tax already remitted by the contractor.
What to prioritize in a platform
A compliant platform should provide:
SDS workflows — documented status decisions with a formal disagreement process
Audit trails — evidence retained for every engagement
Vetted umbrella partners — due diligence against non-compliant and mini-umbrella schemes
Contract and working-practice alignment — contracts must reflect actual day-to-day realities
PAYE or payroll route — available for every inside-IR35 outcome
How Proxify handles IR35
Proxify helps clients navigate the complexities of global workforce regulations, including the UK's IR35, with a contractual framework and best-practice guidance designed to mitigate misclassification risks.
Proxify is compliant with global workforce regulations, including the UK's IR35 laws, and its structure eliminates misclassification risks, providing a seamless and risk-free hiring experience. Proxify's matching process connects companies with suitable developers within two days on average; each month, over 20,000 developers apply, but only about 1–2% pass through, including live technical interviews and pair programming.
For UK businesses needing fast, compliant developer hiring with built-in IR35 governance, Proxify offers a structured alternative to navigating recruitment agencies and umbrella arrangements independently.