Services · Mobile app development · Payroll apps
Codeeo provides payroll software development across the UK for employers, payroll bureaux and software businesses that need more control than a packaged product gives. We build the PAYE and National Insurance engine, Real Time Information filing to HMRC, auto-enrolment duties, every statutory payment, Bacs payment files and a payslip app, with the rules for England, Scotland, Wales and Northern Ireland handled in one system. The result is a payroll you can audit, extend and own.
We work with UK clients remotely and have no office in the UK. A team of 80+ in Dubai, Riyadh and Karachi runs discovery, design reviews and test sign-off by video call. Codeeo has delivered 200+ projects across the UAE and the US and holds a 4.7 rating from 23 Google reviews.
200+ companies servedFrom a first store to an ADX listed developer
Core capabilities
Payroll in the UK is governed nationally but not uniformly. HMRC runs PAYE and expects a Full Payment Submission on or before every payday. The Pensions Regulator oversees automatic enrolment. Statutory pay schemes have their own qualifying tests and recovery rules. Income tax bands differ for Scottish taxpayers, Welsh rates are set separately even when they match England's, and Northern Ireland has its own employment law alongside the same tax system. National Minimum Wage enforcement sits with HMRC, and data protection with the ICO under UK GDPR.
An employer with staff in Glasgow, Cardiff, Belfast and Leeds has to get all of that right in the same run. So does a bureau running hundreds of client payrolls, or a software company whose customers expect payroll inside its HR platform. The capabilities below form the national core; we add the sector rules your business needs on top, and we test each against HMRC's published guidance and your own historic payslips.
The engine applies rest of UK, Scottish and Welsh tax bands according to the code prefix HMRC issues, which follows where an employee lives rather than where they work. Student loan plans, including the plan used for Scottish borrowers and postgraduate loans, are deducted from HMRC notices, so a move from Edinburgh to Bristol is handled by a code change, not a manual fix.
Each employee is taxed under the right nation's rules automatically.
Full Payment Submissions and Employer Payment Summaries are built to HMRC's technical specifications and tested through HMRC's developer and test services before live filing. If you plan to sell the software, we prepare for HMRC's recognition process so it can be listed for other employers to use.
Submissions are accepted first time and every response is stored.
Workers are assessed every period as eligible jobholders, non-eligible jobholders or entitled workers. The system handles postponement, enrolment letters, opt-outs and refunds, re-enrolment and contribution files for the schemes you use, and keeps the evidence behind your declaration of compliance to The Pensions Regulator.
Pension duties are met with a full record for any review.
Statutory sick pay, maternity, paternity, adoption, shared parental, parental bereavement and neonatal care pay are calculated with their qualifying checks, notice dates and average weekly earnings rules. Recoveries, including small employers' relief where it applies, are totalled for the Employer Payment Summary.
Every statutory scheme is calculated and reclaimed consistently.
For each pay reference period, the system works out pay that counts towards the National Minimum Wage or National Living Wage, subtracts deductions that reduce it, and compares the result with the rate for the worker's age. Salaried staff on long hours are checked too, since they are a common source of underpayment.
Underpayments are caught before the run is approved, not after an inquiry.
Company cars, private medical cover and other benefits can be payrolled, with taxable values spread across periods, and salary sacrifice arrangements are modelled with their effect on pay, tax and pensions. Reporting is kept ready for year end, and the design leaves room for changes HMRC makes to how benefits are reported.
Benefits are taxed in year rather than corrected later.
Apprenticeship levy, Employment Allowance claims and employer National Insurance are calculated across connected companies where the rules require it, and reported on the Employer Payment Summary. Finance teams see employer cost per entity, region and cost centre.
Employer liabilities are visible before the payment to HMRC is due.
Approved runs produce Bacs Standard 18 files for submission through your bank's channel or a Bacs approved bureau, with dual approval, bank detail change controls and alerts for unusual payments. Faster Payments handle urgent corrections outside the normal cycle.
Payments go out on time with protection against fraud.
Sites in different cities, companies with separate PAYE schemes and groups with regional allowances are set up as structured data, so adding a new office or acquired business is configuration rather than new code. Each entity files under its own employer reference.
Growth across the UK does not mean a new payroll each time.
Employees get itemised payslips, P60s, P45s and P11D information in an app or web portal, with hours shown where pay varies by time worked. They can update personal details within limits you set, and changes route to payroll for approval.
Employees across every site see the same clear information.
Who this is for
Custom payroll software development in the UK is a significant decision, because payroll carries legal duties every single payday. We recommend it when a packaged product forces repeated workarounds, when payroll must sit inside a wider system you already own, or when payroll is part of the product you sell. As a payroll software development company working remotely with UK clients, we see four situations most often. Each begins with discovery by video call, where we read recent payslips, submissions and exception reports to find the rules that cause the most manual effort today.
Retail chains, care providers, utilities and service companies often employ people from Aberdeen to Plymouth. Different tax bands, regional allowances, shift patterns and several pension schemes push a standard product to its limits. We build one payroll with consistent rules, nation-aware calculations and reporting by region, connected to your HR and time systems so starters and hours arrive without rekeying. Regional managers approve hours for their own sites, while one central team owns the rules.
Northern Ireland employment law is reviewed separately where it affects pay.
Bureaux run many client payrolls on different calendars, each under its own employer reference, with client approvals and Bacs output to manage. We build multi-client platforms with strict data separation, client portals for sign-off and bulk processing for the busiest days of the month. Each client's pension scheme, pay calendar and approval contacts are held separately, and staff permissions can be limited to the clients they serve, so a new payroll officer sees only their own portfolio.
If your customers already use your platform for HR, rota or time, payroll is a natural addition, but it brings HMRC filing, recognition and annual legislative updates. We build the payroll module to sit inside your product, prepare it for HMRC testing and recognition, and can stay on to deliver each April's changes.
Recognition is granted by HMRC, not by us; we prepare the software for it.
Organisations with pay scales, incremental progression, multiple pension schemes and grant-funded posts need payroll that reflects national pay agreements and funding rules. We model pay spines, increments and cost allocations to funds, and produce reports that satisfy trustees, auditors and funders. Where staff belong to public service pension schemes, contribution tiers and employer rates are configured per scheme, and returns are produced in the format each scheme administrator expects.
How we work together
Employers usually begin with a fixed scope build for one entity or region, then roll out across the rest of the business once parallel runs prove the numbers. Software companies and bureaux tend to prefer a dedicated team, because payroll becomes a product that changes every year. A retainer suits organisations that own a finished system and want annual updates and support. Every engagement has written scope and acceptance tests, and collaboration runs entirely by video call and shared tools. Because UK payroll has a fixed annual rhythm, we plan major releases away from tax year end and from your own busiest pay periods.
A defined build with a deadline
We agree what the product has to do, write it down with a price and a date, and build exactly that. Changes are priced before they are made, not discovered on the invoice.
A product that keeps evolving
Named engineers who work your hours, join your standups and stay on the codebase. You direct the backlog; we own the quality of what ships.
Something live that needs looking after
A monthly block of hours for improvements, fixes and the small requests that otherwise wait months. Unused hours carry for a quarter.
Technology
We choose technology for calculation accuracy, full audit history, secure hosting and long-term maintainability. Where payroll data sits is agreed during discovery to fit your UK GDPR position and any public sector or client requirements. Architecture and rule documentation are handed over so another team can maintain the system.
01Mobile
02Data and cloud
03Marketing and tracking
When workarounds, integration needs or your business model make a package the harder option.
A standard product is often right for salaried staff on one scheme. Custom work earns its keep when you employ people across several nations with complex pay rules, run payroll for many clients, need payroll inside your own platform, or plan to sell payroll as a product. Cost depends on pay groups, statutory scope, integrations, data migration and whether HMRC recognition is needed. We explain each factor in discovery.
Schedule a free consultation and get a written recommendation, with costs, before you commit to anything.
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