7 mistakes I see in every vibe-coded MVP (and how to avoid them)

I’ve spent the last year looking at hundreds of vibe-coded apps. Some I built. Some I audited for clients. Some I found by searching for things people shipped on Twitter and trying them out. The same seven mistakes show up over and over. This article is the list I wish someone had handed me before I shipped my first vibe-coded MVP.

Some of these will sound obvious. They weren’t obvious to me at the time, and they’re not obvious to most people shipping their first AI-built app. Read them anyway. Each one is fixable, but only if you know to look.

Mistake #1: Building before you have a real user

The most common failure mode. Someone gets excited about an idea, fires up Blink or Lovable, and spends two weeks building a beautiful prototype. Then they launch to crickets. Or worse, they launch to people who say “cool!” and never come back.

The fix is uncomfortable: before you build, find someone who would pay for what you’re about to build. Not “would use for free.” Would actually pay. If you can’t find 5 of them, your idea is wrong or your scope is wrong, and you should not start building yet.

How to find them: post in relevant communities, reach out to people who’ve complained about the problem in public, run a fake landing page and see who signs up. The 5-pay-customers test is the cheapest validation you can do, and almost nobody does it.

What “real user” actually means: someone with a real problem, who has tried to solve it before (with spreadsheets, with an existing tool, with manual work), and who would pay real money to solve it. Not someone who likes your idea in the abstract.

Mistake #2: Trying to ship the whole idea in v1

Vibe coding makes it tempting to build a complete product. You describe a CRM, you get a CRM. You describe a course platform, you get a course platform. The tool is so good at generating the obvious features that you forget to ask which features actually matter.

The fix: ruthlessly cut v1 down to the one thing that, if it worked, would make a user pay. Everything else is v2. The CRM is “add a contact, log a deal, mark it closed.” The course platform is “pay, see the course, watch a video.” Everything else — analytics, integrations, advanced settings, mobile apps — is a distraction until you have paying users.

A useful test: if you can describe the v1 in two sentences, you’re scoped right. If it takes a paragraph, you’re building too much.

A second useful test: the “weekend build” test. Could a focused developer, using the AI tool, build v1 in a single weekend? If not, v1 is too big.

Mistake #3: Treating the AI output as finished code

The AI generates code that works for the prompt. It does not generate code that’s well-architected, secure, or maintainable. It generates code that passes the smoke test.

This matters because: when you want to add a feature 3 weeks later, you’ll discover the code is organized in a way that makes your new feature hard. When you have a security incident, you’ll discover the AI didn’t add the input validation it should have. When your user count grows, you’ll discover the database queries are N+1 disasters.

The fix isn’t to learn to write code from scratch. The fix is to learn enough to read what the AI wrote and ask the right questions. Specifically:

• Where is the user data stored? Can I export it? Is it backed up?
• How does authentication work? What happens when a user changes their email?
• Where does the input get validated? What happens with a malicious payload?
• What does the database schema look like? Can I add a column without breaking the app?

You don’t have to understand the code. You have to understand the architecture. The architecture is what determines whether your app survives its first 100 users.

Mistake #4: Skipping the legal setup

This one is the most expensive to fix later. Privacy policy. Terms of service. Cookie policy. Tax setup. Business entity. Payment processor terms.

Every vibe-coded MVP I’ve seen launched without these. Some launched without them and got lucky. Most launched without them and got a strongly-worded email from a payment processor, a GDPR complaint, or a tax surprise.

The fix: spend $200-500 in the first month on legal templates (Termly is fine, or a one-time consultation with a lawyer). Set up Stripe Atlas or equivalent in the first week. Add a privacy policy and terms of service to your footer before you add a “buy now” button.

This is not optional. This is not something you’ll do later. Do it now, before you take a single dollar from a customer.

Mistake #5: No plan for when the tool is gone

Every vibe coding tool will, eventually, do one of these: change pricing, change features, get acquired, shut down, or pivot in a way that breaks your app. The lock-in risk is real.

The fix: before you commit to a tool, know what your exit looks like. Can you export the code? Can you self-host? Can you migrate to a different tool? If the answer is “I don’t know,” you’re taking a real risk with your business.

Tools that currently let you export: Blink (yes), Bolt (yes), Replit (yes). Tools with limited or no export: a few of the smaller competitors. Check the docs, ask in their Discord, and don’t take marketing at face value.

The other half of this: back up your data. Even if the tool lets you export the code, your database, your user-uploaded files, your content — all of that should be backed up somewhere you control. Daily exports to a S3 bucket, a weekly email of important tables, whatever. Don’t find out about a data loss the hard way.

Mistake #6: Building features nobody asked for

This is the inverse of mistake #2. Instead of cutting scope, you add scope. AI tools make this easy — you describe a feature, you get a feature. Before you know it, you have 30 features and 5 users.

The pattern looks like: someone in a user interview says “it would be cool if you could…” and you add it. A competitor has a feature, so you add it. You imagine a future where a certain user needs it, so you add it.

The fix: every feature starts with a user who has asked for it specifically, who is willing to pay for it, and who will be disappointed if you don’t ship it. If the user doesn’t exist, the feature doesn’t ship.

Maintain a feature backlog with three columns: “users have asked for this,” “I think this would be cool,” “competitors have this.” Only the first column gets built. The second column gets revisited quarterly. The third column gets ignored unless users ask for it.

Mistake #7: No analytics, no feedback loop

The most common failure mode after launch. You ship the MVP, you get a few signups, and you have no idea what people are doing. Are they signing up and not coming back? Are they hitting a wall on a specific page? Are they using the feature you spent the most time on?

Without data, you’re guessing. With data, you can fix the real problems.

The fix: set up analytics on day one. Plausible or Fathom are privacy-friendly and don’t require a cookie banner. Track: signups, active users (daily, weekly), feature usage, conversion to paid. Add a feedback widget (Canny, or just a Typeform) so users can tell you what’s wrong.

The mistake is not having analytics. The bigger mistake is having analytics and not looking at them. Set a weekly reminder. Read the data. Talk to the users who are struggling.

The actual fix for all 7

The pattern across all of these: build less, ship faster, learn more.

The vibe coding tools are so good at generating features that the limiting factor is no longer “can I build this.” It’s “should I build this, and is anyone going to use it?” Most of these mistakes are about answering the second question poorly.

The single best thing you can do this week: pick the most important user of your app, find a way to talk to them for 30 minutes, and ask them what they’re actually struggling with. Then build that. Not the thing you think they need. The thing they tell you they need.

That’s it. That’s the post.

FAQ

Are these mistakes only for AI-built apps?

No, mostly. Most of these are mistakes that show up in any MVP, built by anyone. The reason they show up more in vibe-coded apps is that AI tools make it easy to ship a working prototype, which means builders get to the ‘real mistakes’ phase faster. A developer building from scratch would catch some of these earlier, but the same mistakes are common in code-first MVPs too.

Which mistake is the most expensive?

Mistake #1 (no real users before building) and mistake #4 (skipping the legal setup) are the two that have killed projects I’ve seen. #1 wastes months of building time on something nobody wants. #4 creates real liability — and the cleanup cost is much higher than the setup cost.

What’s the one thing I should fix today?

If you already have a vibe-coded app, fix mistake #7 (no analytics) first. You need to know what your users are actually doing. If you haven’t started yet, fix mistake #1 (talk to users first) before you write a single prompt.