Custom fields: collect the right data before day one

The conventional wisdom is simple: collect email, nothing else. Fewer fields means higher conversion. That is true as a default. But it is not the whole picture.

The founders who get the most out of their waitlist do not just have a list of email addresses. They have a structured dataset that tells them who their early audience is, what problems they are trying to solve, and which segment to prioritise for the beta.

They got that data by asking one or two targeted questions at signup — and by asking them the right way.

When extra fields are worth it

Adding a field costs you some signups. The question is whether the data is worth more than the signups you lose.

It usually is when:

• You need to segment your audience. If your product is for freelancers but you are getting interest from enterprise teams, knowing that early changes your roadmap. A simple "what best describes you?" dropdown costs maybe 5 to 10% of signups and tells you whether you are building for the right people.

• You need criteria to prioritise beta invites. If beta access is limited, you need a way to decide who gets in first. "What is your biggest pain point with [problem]?" gives you something to sort by that is far more useful than signup date.

• Onboarding requires it. Some products need a company name, a role, or a use case to set up correctly. Better to collect it upfront than ask again after someone has already committed.

When to leave it out

• When you are in pure growth mode and every signup matters equally
• When you can gather the same data from a follow-up email after signup
• When the question is interesting but will not change any decision you make

How to frame the ask

The wording matters more than most people expect. Here is what works:

Explain why you are asking

"Help us build the right product for you" beats a bare label. People are more willing to answer when they understand the purpose.

Match the field type to the data you need

Question type	Best field type
Which category fits you?	Dropdown / radio
How urgent is this for you?	1–5 scale
What are you trying to do?	Short text (optional)
Describe your situation	Long text (optional)

Use text boxes only when you genuinely need open-ended answers. A dropdown is faster to complete and easier to analyse.

Mark optional fields as optional

This reduces anxiety for people who are unsure how to answer. You lose some completions, but the ones you get are more considered.

Put the custom field after email, not before

Once someone has typed their email address, they are invested. They are more likely to complete an extra field than someone who has not yet committed to signing up.

What to actually do with the data

Data only matters if you use it. Here are four concrete ways:

1. Segment your launch emails Founders and designers care about different things. A segmented launch email that speaks to each group outperforms a generic blast. If you know who is on your list, write to them specifically.

2. Sort your beta invite list Filter by the response that best matches your ideal early user and work down from there. This alone is worth collecting the data.

3. Share aggregate results publicly "67% of people on our waitlist deal with X problem" is compelling building-in-public content and validates the problem you are solving to future signups.

4. Feed it into your roadmap A dozen people saying they need a specific integration is a stronger signal than one customer request in a meeting. Custom field data turns anecdote into evidence.

A simple starting point

If you are unsure where to begin, add one select field after the email input:

What best describes you?

• Founder / solo maker
• Product manager
• Designer
• Developer
• Other

That single field, completed by even half your signups, will tell you more about your audience than most user research sessions produce.