Interim CTO
A full-time but temporary CTO who runs engineering through a transition, usually 3 to 12 months, until the permanent hire takes over.
An interim CTO is a full-time, temporary executive who runs engineering during a transition, usually for 3 to 12 months. The trigger is a vacuum: the previous CTO resigned mid-fundraise, was let go, or the company outgrew them before a succession plan existed. The interim steps in at full capacity, stabilises the org, and hands over to the permanent hire they often help recruit.
The difference to a fractional CTO is commitment shape, not seniority. Fractional means 1 to 3 days a week, ongoing, for a company that needs CTO-level authority without a full-time presence. Interim means five days a week with a planned end date, for a company that has a full-time-sized hole right now. Pick by the size of the hole, not by which title sounds more senior.
Worked example: a scale-up loses its CTO eight weeks before a technical due diligence. Forty engineers, three teams, no deputy. A fractional operator at two days a week cannot absorb that. The org needs someone in every leadership meeting, every escalation, every diligence call, and that is an interim mandate. The mirror case, a seed startup with four engineers and a slipping roadmap, has a two-day-a-week problem. Paying a full-time interim there burns runway on presence nobody needs.
The Austrian legal nuance mirrors the fractional model: an interim CTO is normally engaged as a Dienstvertrag or freier Dienstvertrag, because the deliverable is ongoing judgement and availability, not a fixed work product. The honest trade-off of interim is the cliff: everything the interim learned walks out at handover, so the mandate must include documenting decisions and recruiting the successor. An interim who is vague about their own exit plan is planning to stay, and that is a different, more expensive product.
Wavect’s engagements are fractional by design, 1 to 2 days a week with two founders on every engagement. If you have a true vacuum that needs five days a week, hire interim, and we will tell you exactly that on the first call. Where the two shapes overlap is covered in Fractional CTO Austria.