--- title: Expatriate Payroll Articles, Insights and Resources | Certino | Aaron Parfitt description: Aaron is Head of Engineering at Certino, where he leads the team that builds and runs the platform and the country tax engines behind every calculation. He focuses on making Certino's calculations fast, secure and reliable, whether clients use the platform or connect through the API. He's based in Cardiff, UK. --- [Skip to content](https://www.certino.com/blog/author/aaron-parfitt#main-content) [![Certino Ltd. Logo](https://www.certino.com/hubfs/march-2021/globals/certino.svg)](https://www.certino.com/blog/) ![](https://cdn2.hubspot.net/hubfs/234700/_nov_2019/globals/nav.svg) - [Home](https://www.certino.com) - [Platform](https://www.certino.com/platform) - [Managed service](https://www.certino.com/managed-service) - [About us](https://www.certino.com/about-us) - [Blog](https://www.certino.com/blog) - [Book a call](https://www.certino.com/book-a-consultation) Author # Aaron Parfitt ![Aaron Parfitt](https://www.certino.com/hubfs/aaron-parfitt-no-shadow.jpeg) ## Posts by Aaron Parfitt Aaron is Head of Engineering at Certino, where he leads the team that builds and runs the platform and the country tax engines behind every calculation. He focuses on making Certino's calculations fast, secure and reliable, whether clients use the platform or connect through the API. He's based in Cardiff, UK. [All](https://www.certino.com/blog) [Shadow Payroll](https://www.certino.com/blog/tag/shadow-payroll) [International Tax](https://www.certino.com/blog/tag/international-tax) [Global Mobility](https://www.certino.com/blog/tag/global-mobility) [Technology](https://www.certino.com/blog/tag/technology) [![](https://www.certino.com/hubfs/where-ai-shouldnt-do-the-maths-cover.png)](https://www.certino.com/blog/why-we-dont-let-ai-do-our-maths) Shadow Payroll ### [Why we don’t let AI do our maths](https://www.certino.com/blog/why-we-dont-let-ai-do-our-maths) It’s an odd thing for a tech company to admit in 2026, but we don’t let AI anywhere near our maths. That isn’t because we’re sceptical of ... 9 Oct 2026 [Read →](https://www.certino.com/blog/why-we-dont-let-ai-do-our-maths) [![](https://www.certino.com/hubfs/the-api-the-product-cover.png)](https://www.certino.com/blog/the-api-the-product) Technology ### [The API is the product: how Certino plugs into the systems you already use](https://www.certino.com/blog/the-api-the-product) Most businesses that deal with international employees already have their systems in place. An HR system, a mobility platform, a payroll ... 7 Oct 2022 [Read →](https://www.certino.com/blog/the-api-the-product) Book a call ## Talk to a shadow payroll specialist A short call to look at how you run shadow payroll today and where Certino fits. No obligation. [Book a call](https://www.certino.com/book-a-consultation) Your payroll data, properly protected Independently audited security, built for sensitive pay data. ![iso-27001-1](https://www.certino.com/hubfs/iso-27001-1.png) ISO 27001:2022 ![AICPA SOC 2](https://www.certino.com/hubfs/march-2021/globals/aicpa.png) SOC 2 Type II ![gdpr](https://www.certino.com/hubfs/gdpr.png) GDPR Compliant ![certino-white](https://www.certino.com/hubfs/march-2021/globals/certino-white.svg) ###### Links - [Shadow payroll guide](https://www.certino.com/shadow-payroll) - [Siemens case study](https://www.certino.com/siemens) - [Platform](https://www.certino.com/platform) - [Managed shadow payroll](https://www.certino.com/managed-service) - [Research & insights](https://www.certino.com/blog) - [Book a demo](https://www.certino.com/book-a-consultation) ###### Contact - [+44 (0) 207 118 1405](tel:+44(0)2071181415) - [enquiries@certino.com](mailto:enquiries@certino.com) - [![linkedin](https://www.certino.com/hubfs/linkedin.svg)](https://www.linkedin.com/company/certino/) © 2026 Certino Ltd. All rights reserved. Company no. 10810451. Registered at 25 Moorgate, London EC2R 6AY - [Cookie policy](https://www.certino.com/cookie-policy) - [Terms & Conditions](https://www.certino.com/terms-conditions) - [Privacy policy](https://www.certino.com/privacy-policy)