A CTO, or chief technology officer, is the senior executive responsible for the technology a business builds and sells. The CTO sets technical strategy and architecture, leads the engineering team and makes sure the product can scale securely, reliably and at a sensible cost.
What the role covers
The CTO faces outwards, towards the product and the customer. Responsibilities include choosing the technology stack, designing the architecture, hiring and leading engineers, setting development practices, and managing technical debt, security and uptime.
In technology businesses the CTO also explains the product's technical strength to investors and acquirers, and often leads the technical part of due diligence.
How it works in a UK business
In UK SaaS businesses and tech-enabled scale-ups, the CTO is frequently a co-founder who wrote the first version of the product. As the company grows, the role shifts from coding to leadership, process and hiring, which not every founding engineer wants to do.
Outside technology companies, the internal systems side of technology is usually owned by a CIO or IT director rather than a CTO.
The fractional option
Early-stage and growing businesses often need senior technical judgement before they can justify a full-time CTO. A fractional CTO provides architecture decisions, team leadership and investor-ready technical credibility on a part-time basis. Leadership Services provides fractional CTOs from its bench of senior directors, from £1,795 per month.
Frequently asked questions
What is the difference between a CTO and a CIO?
A CTO focuses on the technology the business sells, such as its software product or platform. A CIO focuses on the internal systems the business runs on, such as ERP, CRM, infrastructure and data. Product companies tend to need a CTO first, while most other businesses need a CIO or IT director.
Does a startup need a CTO from day one?
Not always. Many startups build an early product with a technical co-founder, a development agency or a fractional CTO. A full-time CTO becomes important when the engineering team grows, the architecture must scale, or investors want a dedicated technical leader.
Last updated: 5 November 2026