Before investors call your customers, interview those customers yourself using the questions an investor will ask: how central your product is to their work, what would break if it disappeared, whether they looked at alternatives at renewal, and what they would honestly tell a peer. Run it as a short AI-moderated interview with 15 to 30 customers a few weeks before you raise. You will learn what diligence is going to hear while there is still time to fix it, you will know which customers are genuinely strong references, and you will have a customer evidence report you can share with investors, with consent.
Why customer calls decide more rounds than founders expect
Founders prepare the deck, the model and the data room. The customer calls often get a two-line email to "a few happy customers" the night before. That is backwards, because investors weight them heavily.
- Investors spend real time on diligence and talk to references. In one of the largest surveys of venture capitalists (885 VCs at 681 firms), Gompers, Gornall, Kaplan and Strebulaev found firms spend an average of 118 hours on due diligence per investment, and summaries of the paper report around 10 reference calls per deal.
- The product and the market matter alongside the team. The same survey found 95% of firms rate the management team as an important factor, but 83% also name the business model, 74% the product and 68% the market. Customer calls are where investors test the last three.
- Rounds are hard to come by, so each one carries more weight. Carta's data puts the median time between seed and Series A at 1.9 years in Q4 2025, after several years of the gap growing. A process that stalls on weak customer calls can cost months you may not have.
The uncomfortable part is that founders often do not know what their own customers will say. Your champion may love you while their manager is evaluating a cheaper tool. The customer you consider your best reference may describe you as "fine, but we could switch". Investors will find that in a 20-minute call. You should find it first.
What investors are listening for
Most customer reference calls in venture diligence boil down to five questions, whatever the wording:
- How did you come to use this, and what were you doing before? This tests whether the problem was real and painful.
- What would break if it went away tomorrow? This tests dependency. "We'd go back to spreadsheets and it would hurt" is strong. "We'd probably find something else" is not.
- Did you evaluate alternatives at renewal? This tests switching risk and how competitive the category is.
- How has your usage changed? Growing usage and expansion across teams signal retention. Shrinking usage is a warning even if the customer is polite.
- What would you tell a peer, honestly? This is where the caveats come out: support, missing features, price.
Good investors also listen for what is not said. A customer who cannot name a specific moment the product came through is a weak reference, however warm they sound.
How to run your own pre-diligence customer study
Interview broadly, not just your favourites. Include your largest accounts, a few smaller ones, recent signups and at least a couple who reduced usage. Many investors ask for a full list and pick for themselves, or find customers through their own networks. A study of only your champions tells you nothing you do not already know.
Use the investor's questions, not friendlier ones. If you soften the questions, you get a softer picture than the one diligence will see.
Do it four to eight weeks before you raise. That leaves time to fix a support issue, close a feature gap a key account keeps mentioning, or have a direct conversation with an account at risk.
Never script or coach customers. The point is to learn, not to rehearse their answers. Investors can tell when a reference has been coached, and it damages trust far more than an honest caveat. Ask customers' permission before you name them as references, and before you quote them anywhere.
Questions to use
- "Take me back to before you used [product]. What were you trying to solve, and what were you doing instead?"
- "How central is it to your work today? What would actually break if it disappeared?"
- "On a scale of 1 to 10, how dependent is your team on it day to day?" (scale, then probe the number)
- "Tell me about a specific time in the past six months when it really came through, or really fell short."
- "When your contract last came up for renewal, did you look seriously at alternatives?" (yes/no, then probe)
- "If a peer at another company asked whether to use it, what would you tell them, including the parts that aren't in the case study?"
Reading the results
Sort what you hear into three buckets:
- Strong references. Specific stories, high dependency, growing usage. Ask these customers if they would be willing to take an investor call.
- Fixable concerns. A missing integration, slow support, an onboarding gap. Fix what you can before the raise and be ready to explain the rest. Raising a known weakness yourself, with a plan, lands better than an investor discovering it.
- Real risk. An account evaluating a competitor, or a champion who has left. You need to know about these before an investor does, both for the raise and for the business.
How to set it up in Koji
- Start from the Pre-Investment Customer Due Diligence template. It is the study an investor would run on your customers: it asks what they did before, what would break if the product disappeared, how dependent they are on a 1 to 10 scale, whether they evaluated alternatives, how usage has changed and what they would tell a peer. Running it on your own customers shows you what diligence will hear. Change the company name to yours and set the decision to "which customers to offer as references, and what to fix before the raise".
- Keep the hard questions. Koji supports open-ended, scale, single choice, multiple choice, ranking and yes/no questions, each with its own follow-up depth. Keep the dependency scale and the renewal yes/no so you get comparable numbers across accounts, and let the interviewer probe the answers. See the structured questions guide.
- Preview it. Take the interview yourself on the Preview tab, by text or voice. Previews are free and never appear in the report.
- Send each customer their own link. Import your customer list from a CSV and every contact gets a personal invite link, so answers show up against their name and you can see who has not started (Interviews and Enterprise plans). Offer text or voice; voice needs the Interviews or Enterprise plan.
- Read the report. It opens with what you learned and the reasons behind it, and every finding is one click from the interviews it came from. The analysis drawer gives each interview its own summary, themes, quotes and quality score, which makes it quick to sort accounts into strong, fixable and at risk.
- Share it, with consent. You can publish the report and send investors a public link, no login needed. Only do this if customers agreed to their answers being shared, and say clearly that you ran the study yourself. Investors will still run their own calls; your report shows you know your customers and are not hiding anything.
What it costs
A text interview costs 1 credit and a voice interview 3. Free includes a one-time grant of 10 credits, enough to try it on a handful of friendly accounts. Insights is €29 a month with 29 credits. Interviews is €79 a month with 79 credits, and includes personal invite links and voice. Interviews that score under 3 out of 5 on quality do not use credits and stay out of the report. Check the pricing page for current figures.
What you walk into the raise with
- A reference list you have tested. Not the customers you hope will say nice things, but the ones whose stories you have already heard.
- A short list of known weaknesses with a plan. Investors expect weaknesses. They do not expect to find them first.
- Customer language for the deck. The way customers describe the problem and the dependency in their own words is stronger than any slide you write.
- Early warning on accounts at risk. Even if you do not raise, knowing which customers are wavering is worth the effort.
Why Koji for pre-diligence customer research
| What a founder weighs | Calling customers yourself | Survey | Koji |
|---|---|---|---|
| Customers speak candidly | Hard when the founder asks | Short answers | They talk to an interviewer, not to you |
| Uses the investor's questions | Easy to soften | Only fixed answers | Due diligence template, with follow-up |
| Covers 15 to 30 accounts | Weeks of calls | Yes | Days, in parallel |
| Comparable across accounts | Varies | Yes | Same questions, dependency scores charted |
| Shareable evidence | Your notes | A chart | A report with quotes and a public link |
Koji does not replace the calls you make yourself to your most important accounts, and it does not replace the investor's own diligence. It makes sure the first time you hear a customer's honest view is not in a partner meeting.
Start before the round
Create a study from the Pre-Investment Customer Due Diligence template, add your name and your customer list, and preview it. You can start free with 10 credits, and Koji for founders covers the other studies founders run.
For more on the method, read the guides to customer reference interviews, customer research for investors and commercial due diligence interviews, which show the same process from the investor's side. On the blog, product-market fit research and the pivot decision playbook cover the questions that come before a raise.
