Your project needs technical leadership, but a permanent CTO position would be premature or is currently vacant. When you look for support, you come across the terms external CTO, interim CTO and CTO as a Service, which sound alike. In this article I sort them out and show when each model fits.
What a CTO is responsible for
CTO stands for Chief Technology Officer, the person with overall technical responsibility in a company. This person decides on architecture, stack and vendors. They set the rules by which the team writes and releases code, and they lead the developers.
A CTO also translates between management and technology. When management wants to know what a feature costs or what risk a decision carries, it needs a reliable answer.
Whoever fills this role doesn’t have to be an employee. The three terms describe ways of filling it from outside. They differ mainly in how much responsibility the person takes on and for how long.
Interim CTO as a temporary executive
The professional association Dachgesellschaft Deutsches Interim Management (in German), DDIM for short, describes interim management as the fixed-term deployment of external executives for management tasks. According to DDIM, interim managers take on positions at the first or second management level with authority to direct staff. Unlike consultants, they carry entrepreneurial responsibility and carry out the tasks themselves inside the company.
An interim CTO is therefore a temporary executive who fills the CTO position completely. According to DDIM, almost half of all assignments last between six months and a year.
This model fits when an existing position suddenly becomes vacant and someone has to take over the leadership until it’s filled again. A restructuring with a clear end can also be a reason, such as the move to a new platform. In both cases the company needs a full executive who makes decisions and leads the team.
External CTO and CTO as a Service
I use the other two terms for the same model. An external CTO takes on technical leadership without being employed by the company and without filling a full position. The term fractional CTO is also common for it. CTO as a Service stresses that this leadership is agreed as an ongoing service, with fixed tasks and a scope per month.
The difference from an interim CTO lies in the scope. An interim CTO replaces a whole position for a limited time. An external CTO takes on the part of the leadership your project needs right now, and that part can grow or shrink.
This fits a few typical situations.
- Your team is already building, but no one owns the overall technical direction.
- You’re starting or running a company and need decisions on architecture, stack and vendors.
- Your agency needs a technical partner for a client project.
How it differs from consulting
According to DDIM, consulting delivers analyses and recommendations, while decisions and implementation stay with the client. That’s enough when you need a one-off assessment, such as a code review of an existing application before further development.
An external CTO, by contrast, stays in the project after the recommendation. They make decisions with you and guide the implementation until your team can continue without them.
Which model suits you
Three rules of thumb help you decide.
- If a position is vacant and must be fully filled until it’s staffed again, you’re looking for an interim CTO.
- If you need decisions and guidance but not a full position, an external CTO fits.
- If you only need a one-off assessment, consulting or a code review is often enough.
Also clarify who carries the responsibility in the end. An interim CTO takes it on with the position for the duration of the assignment. With an external CTO, you share the responsibility, so tasks and decision-making authority should be set down in writing.
What our service covers
Under the name CTO as a Service, we take on as much technical leadership as your project needs. We define the architecture, stack and interfaces with you and document the decisions. We evaluate vendors, hosting and tools. Our criteria are cost, operational effort and dependencies.
We review code, define quality standards and set up tests and release workflows. Within your team we plan and prioritize with you and answer technical questions during day-to-day operations. We work in your tools and workflows and never make decisions without your team. We also support you with technical interviews and take-home assignments. For new developers, we automate onboarding with access, environments and checklists.
We currently own all technical decisions and the implementation for a financial advisor’s investor portal. We also run about ten client and product projects on Cloudflare®. We don’t require a move there, because we evaluate your existing environment and recommend changes only when they lower costs, simplify operations or reduce dependencies.
If you’re looking for an interim CTO, we can also take on technical leadership for an agreed period. We then agree on tasks and availability in advance.
How we work together
- We review code, infrastructure and open decisions and discuss with you where technical leadership is missing.
- We agree on tasks, availability and the scope per month, and the scope can be adjusted later.
- We join your planning sessions, review code continuously and stay available for technical questions.
- We document decisions, standards and workflows so your team can continue without us.
We work remotely with clients across Germany and internationally, and in-person meetings are possible by arrangement. You can read who is behind Ruxiom and how we work on the About Ruxiom page.
The CTO as a Service page explains how we work as an external CTO. Tell us how your team is set up and which decisions are open. Then we’ll work out the right scope.