The Dev Log › Startup & Business

Validating Your Startup Idea Before Writing a Single Line of Code

By Jezer Niel Blanca, Full Stack Developer · July 28, 2026 · 6 min read

Code is the most expensive way to test an idea. Here is how founders can validate demand with interviews, smoke tests, manual delivery and real commitments.

As a developer, my instinct when I hear a good idea is to start building. It's fun, it feels productive, and it produces something you can see. But code is the most expensive way to find out whether people want something. Before a founder spends months and a serious budget on development, there are faster and cheaper ways to learn whether the idea has legs. In this post I'll walk through the validation steps I recommend to founders before a single line of code is written.

Validation is not asking friends if they like your idea. People are kind, and "that sounds great" costs them nothing. Real validation is collecting evidence that a specific group of people:

Has the problem you think they have.
Cares enough to be actively trying to solve it today.
Will commit something: time, an email address, a signed letter of intent, or ideally money.

Each step up that ladder is stronger evidence than the one before. Compliments are the weakest signal. Payment is the strongest.

The goal of validation isn't to prove you're right. It's to find out as cheaply as possible whether you're wrong.

Step 1: Write Down Your Riskiest Assumptions

Every idea rests on a stack of assumptions. Write them down explicitly, then circle the ones that would kill the idea if they turned out to be false. Typical ones look like:

"Small construction companies struggle to track subcontractor paperwork."
"The office manager is the person who feels this pain and can make the purchase."
"They currently use spreadsheets and email, and they're frustrated with it."
"They would pay a monthly subscription to fix it."

Now you have a test plan. Validation is simply working through those assumptions, riskiest first.

Step 2: Talk to Real People the Right Way

Customer interviews are the highest-value validation activity, and also the easiest to get wrong. The most common mistake is pitching the idea and asking for opinions. Instead, ask about their past behaviour, which is much harder to fake than predictions about the future.

Questions that produce useful answers:

"Tell me about the last time this happened."
"How do you handle it today?"
"What have you already tried to fix it?"
"What does it cost you when it goes wrong?"
"Who else is involved when this comes up?"

Questions to avoid:

"Would you use an app that does this?"
"How much would you pay for it?"
"Do you think this is a good idea?"

Rob Fitzpatrick's book The Mom Test is a short, excellent guide to this style of interviewing, and I often recommend it to founders. Aim for enough conversations that you start hearing the same stories repeated. When the patterns stop surprising you, you've learned what the interviews can teach.

Listen for Workarounds

The strongest signal in an interview is a workaround. If someone has built a complicated spreadsheet, hired an assistant, or stitched three tools together to deal with a problem, the pain is real. If they shrug and say it's a minor annoyance, it probably isn't worth a product.

Step 3: Run a Smoke Test

Once interviews suggest the problem is real, test whether people will take action. A smoke test is a simple landing page that describes the product as if it exists, with a clear call to action: join the waitlist, book a demo, or pre-order.

A good smoke test page includes:

A headline that states the outcome, not the features.
Three or four short benefit statements based on the language you heard in interviews.
One clear call to action.
Honest wording. "Join the early access list" is fair. Pretending a product exists when it doesn't damages trust.

Then drive a small amount of targeted traffic to it through communities where your audience spends time, direct outreach, or a modest ad test, and measure how many visitors take the action. Decide in advance what result would count as a pass, so you can't talk yourself into a weak signal afterwards.

Step 4: Deliver the Value Manually

This is my favourite step because it teaches you more than anything else. Before automating a solution, deliver it by hand.

Concierge MVP: you personally do the work the product would do. If the product would generate weekly reports, you build them in a spreadsheet and email them.
Wizard of Oz MVP: the customer sees a simple front end, like a form or a basic page, while you fulfil requests manually behind the scenes.

These approaches reveal what customers actually value, which details matter, and which features nobody asks for. They also give you your first paying customers before you've built anything. When the manual work becomes too much to handle, that's a wonderful problem, and a clear sign it's time to build.

Step 5: Ask for Commitment

The final test is whether people will commit something meaningful:

Pre-orders or deposits for consumer and small business products.
Paid pilots for business software, even at a discounted early price.
Letters of intent from larger organizations that can't pay before a product exists.

If people won't commit anything at this stage, listen to that. It may mean the problem isn't painful enough, the audience is wrong, or the offer isn't clear. Each of those is much cheaper to fix now than after launch.

Turning Evidence Into a Build Plan

When validation goes well, you end up with far more than confidence. You have:

The exact words customers use to describe their problem, which becomes your marketing copy.
A clear picture of the one job the first version must do well.
A list of features customers never mentioned, which you can safely leave out.
Early users who are ready to test the MVP and give feedback.

That makes the build faster, cheaper and far more focused. Development becomes execution on a proven direction rather than an expensive experiment.

Wrapping up

Validation is about replacing opinions with evidence: write down your riskiest assumptions, interview people about real past behaviour, test demand with an honest landing page, deliver value manually, and ask for real commitment. It takes weeks rather than months, and it either saves you from building the wrong thing or gives you a clear green light. When you've got that green light, I'd love to help you build the MVP with my team.

Tags: Startups, Validation, Product, Customer Research