When your CTO is leaving your startup, the first two jobs are locking down access and deciding who covers engineering leadership. Searching for a replacement comes later. This plan assumes your CTO is working a notice period and runs over 30 days. If they walked out without notice, do steps 1 and 2 today and pick the rest up as you can.
It's written for a non-technical founder or CEO, or a founder deciding cover for a team they only half-run. For wider reading on this stage, see startup CTO guides on leadership, diligence and the first hires.
What you need before day 1
Three things, and none of them take long.
- One owner of the plan. Usually the CEO. If the departing CTO is also a co-founder, pick someone else on the board or leadership team to run the process, because the leaver shouldn't coordinate their own exit.
- A list of who holds admin on what: cloud accounts, source control, domains, app store accounts, payment and email providers.
- The CTO's employment contract, your shareholder agreement and any option or vesting documents, found and printed or saved in one folder.
How to run the 30-day plan
The ordering below is judgment, not a rule. It puts irreversible risks (access, equity, messaging) before the slower work of covering the role.
1. Secure access and rotate shared secrets (day 1)
List every account where the CTO signs in with a personal login, then move ownership to a company role or a second admin. Rotate the shared secrets they know: database root credentials, cloud root credentials and deploy keys. Kompella, a fractional CTO firm, advises doing this within the first hour of the resignation conversation.
Kompella also advises against revoking the CTO's own access yet while they work their notice. Our recommendation, separate from Kompella's, is to rotate the shared secrets, leave their personal login alone, and cut it on their last day.
2. Read the equity and leaver terms before you talk about them (days 1-3)
Open the shareholder agreement and the option or vesting documents. Look for the vesting schedule, any cliff, the good leaver and bad leaver definitions, and the repurchase price. The section below explains the general mechanics. Terms depend on your shareholder agreement, articles and jurisdiction, so get a lawyer to read yours. This article is general information, not legal advice.
Severance is separate. Kompella notes it depends on the contract and the circumstances, and recommends consulting employment counsel.
3. Tell the team before they hear it elsewhere (days 1-2)
Kompella's guidance is to brief the engineering team within 24 hours. Rumours move faster than announcements, and your engineers will start doing their own career maths the moment they suspect something. Keep the message to three items: what is known, who decides what in the interim, and what does not change (roadmap priorities, pay dates, team structure). Don't promise a successor you haven't chosen.
4. Inventory in-flight work and commitments (days 1-3)
Within the first 48 hours, per Kompella, write down what the CTO has promised or owns: roadmap commitments, vendor contracts and renewals, customer promises with technical dependencies, and hiring in progress. This list becomes your risk register for the next four weeks. Anything with a date on it goes to the top.
5. Tell the board and investors (days 1-3)
Kompella puts the board brief at 24-48 hours for Series A and later companies. Don't walk in with only the news. Bring the interim leadership plan, the access status, the risk list from step 4 and the date you'll decide on a backfill.
6. Capture what only the CTO knows during notice (days 3-21)
Skip the general documentation drive and target what lives only in the CTO's head: why the architecture looks the way it does, relationships with security auditors and key vendors, the hiring pipeline and any deadlines nobody wrote down. Schedule these as recorded sessions with a named engineer in the room. For the pairing, runbook and teach-back method, use the 30-day knowledge transfer plan for a key engineer rather than reinventing it.
7. Put interim leadership in place (week 1)
Someone has to make technical decisions the day after the CTO leaves. Alexis Delaporte, who runs an interim CTO service, lists the risks of an empty seat as weakened leadership, slow or conflicting decisions, a team without guidance, growing technical debt, and pressure on management and investors. You have four realistic options: a senior engineer from the team with a clear decision mandate, a fractional CTO, a full-time interim CTO, or you and the board covering it temporarily. The comparison table below shows what each covers. For what an interim costs and when it's justified, read interim CTO cost and when you need one.
8. Cover the delivery gap and decide the backfill (weeks 2-4)
Most guides stop at leadership. In many startups the CTO is also one of your best coders and your main code reviewer. List what they merged and reviewed over the last quarter. Whoever steps in as interim leader will not also do that work, so decide who takes the review queue and which tickets slip. A short-term senior engineer can absorb delivery while a leader handles direction.
Then set a decision date for the permanent backfill, no later than the end of week 4, and write down the criteria. The next sections give you the options.
What happens to the departing CTO's equity?
It depends on whether they hold shares or options, and on what your documents say. The general mechanics below come from Ashfords, a UK law firm, and its note on leaver provisions published in December 2025.
A good leaver generally left for reasons beyond their control, such as illness, death, redundancy or retirement. A bad leaver was typically dismissed for cause, for example gross misconduct or breach. For both, unvested shares are typically forfeited. Vested shares differ. A good leaver may keep them or sell them at fair market value. A bad leaver's shares are typically repurchased at nominal value (Ashfords gives GBP 0.01 per share as an example).
Resignation is the grey area. Ashfords notes the BVCA model articles no longer treat voluntary resignation as an automatic bad leaver event. Your own articles may still say otherwise.
Ashfords' page covers shareholder leaver clauses. Whether your CTO holds shares, reverse-vested shares or options changes the answer, so check each document.
One consequence for the backfill: a replacement CTO usually expects equity, so the leaver outcome sets what is left to grant. That's judgment, not a sourced figure, and it's worth a quick look at your cap table before you open a search.
Interim, fractional, full-time or a senior engineer: which backfill?
| Option | Covers | Time to start | When it fits |
|---|---|---|---|
| Interim CTO | Leadership, full-time | Within 48 hours (a vendor claim from Alexis Delaporte) | Active crisis or a hard-dated commitment |
| Fractional CTO | Leadership, part-time | Within 5 business days (Kompella's claim for an emergency start) | You need direction but not a full-time seat |
| Full-time CTO | Leadership and ownership | 6-9 months to search, plus 3-6 months to ramp (Kompella) | Long-term owner of engineering strategy |
| Senior engineer | Delivery | HighCircl shortlists in 72 hours | The coding and review gap from step 8 |
Treat the start times as vendors' own claims, not market data. They tell you the order of magnitude: days for part-time or interim cover, roughly 9 to 15 months by Kompella's figures for a permanent CTO who is fully productive.
Kompella suggests about 60 days to evaluate internal candidates, running both paths in parallel for the first 30 days. If you want a permanent search, see how to hire a full-time CTO for the process; this article only covers when to decide.
Mistakes that cost founders the most
Alexis Delaporte names three. The first is recruiting a replacement immediately. The second is naming the lead developer CTO by default. Delaporte's reasons are a legitimacy gap, overload and the risk of a rushed hire. The third is waiting for things to settle. They don't settle on their own, and the team drifts without a decision-maker.
All three share a root: treating the departure as a hiring problem when it's first a leadership and delivery problem.
What this means for your next hire
The decision in front of you is which cover to buy now and when to commit to a permanent hire. Our rule, and it's judgment: buy leadership cover first, delivery cover second, and the permanent hire last.
Leadership cover is quick to start. Kompella puts a fractional start at about 5 business days, against 6-9 months for a full-time search plus 3-6 months of ramp. Alexis Delaporte warns against both reflexes, hiring immediately and promoting by default. So set the backfill decision for week 4, with the cap table and the risk list in front of you, not week 1.
If a lead engineer is covering the CTO's coding, give them a deputy now so review doesn't become the bottleneck. To keep investors informed after the handover, see what to put in an engineering update to the board.
Hiring cover for a departing CTO through HighCircl
HighCircl matches companies with vetted senior engineers across seven European countries in 72 hours, with a shortlist of three to five candidates. There's no minimum hour commitment, so you can add delivery cover now and change it once you've picked a permanent CTO. If an engagement isn't working, HighCircl replaces the engineer at no additional recruitment cost. For leadership cover, see hiring a fractional CTO through HighCircl.
FAQ
What should a founder do first when the CTO resigns?
Secure access. List accounts held under personal logins, rotate shared secrets such as database root, cloud root and deploy keys, and, as Kompella advises, don't revoke the CTO's own access yet (we'd cut it on their last day). Then read the equity documents and brief the team within 24 hours, following Kompella's guidance.
What happens to a CTO's equity when they leave a startup?
It depends on your documents. Per Ashfords, a UK law firm, unvested shares are typically forfeited. Vested shares are usually kept or sold at fair market value by a good leaver, and repurchased at nominal value from a bad leaver. Check your shareholder agreement, articles and jurisdiction with a lawyer.
How long does it take to replace a CTO?
Kompella puts a full-time CTO search at 6-9 months, plus 3-6 months for the new CTO to ramp up. It also claims a fractional CTO can start within 5 business days, so most founders bridge the gap with interim or fractional cover while the search runs.
Should I promote the lead developer to CTO?
Not by default. Alexis Delaporte lists naming the lead developer CTO by default as a mistake to avoid. Kompella suggests about 60 days to evaluate internal candidates, running both paths in parallel for the first 30 days. Run a proper assessment, and consider interim leadership meanwhile so you aren't forced to decide in week one.