Build a SaaS with Vibe Coding & Claude Code

8/10/2025

Building Your First SaaS: A Day-by-Day Walkthrough Using Vibe Coding & Claude Code

Hey everyone! So, you've got a killer idea for a SaaS product. That's awesome. But then comes the hard part, right? The actual building of the thing. For years, this meant you either had to be a coding wizard yourself or have the cash to hire a team of them. But what if I told you that's not the full story anymore?

Honestly, the way we build software is going through a massive shift, & it's pretty exciting. There are these two concepts, "Vibe Coding" & "Claude Code," that are completely changing the game. If you've been putting off your dream SaaS project because the technical side of things feels like a huge wall to climb, then this is for you.

So, what's "Vibe Coding"? It’s a term that’s been floating around, popularized by Andrej Karpathy, a co-founder of OpenAI. It's basically an approach where you guide an AI to write the code for you using natural language. Instead of getting bogged down in syntax & boilerplate, you describe the "vibe" of what you want, & the AI generates the code to match. It’s more about intuition & creativity, which is a HUGE unlock for a lot of people. This makes it possible for even non-programmers to build real, working software.

Then you have Claude Code, which is like the professional-grade engine for Vibe Coding. It's a tool from Anthropic that lives in your command line & can understand your entire codebase. This isn't just a chatbot that spits out code snippets; it's an agentic coding assistant. It can read files, write new ones, run tests, & even help you with your whole development workflow. It’s like having a super-smart junior developer on your team who works 24/7 & never complains.

In this walkthrough, I'm going to show you how you can combine the philosophy of Vibe Coding with the power of Claude Code to build your first SaaS application, day by day. We're going to go from a simple idea to a deployed application. Let's get into it.

Day 0: The "Before We Build" Stuff

Alright, before we jump into writing a single line of code (or, more accurately, a single prompt), we need to get our house in order. Don't skip this part! A little bit of planning here will save you a TON of headaches later.

Market Research (The "Is This a Dumb Idea?" Check)

First things first, you need to make sure you're building something people actually want. This doesn't have to be some super-formal, expensive market analysis. Just do some digging. Who are your competitors? What are they doing well? What are they doing poorly? Where are the gaps? A great way to start is to just hang out where your potential customers are. Are they on Reddit? Twitter? Specific forums? See what they're complaining about. Those complaints are your opportunities.

Nailing Down Your Core Idea & MVP

You can't build everything at once. You need to define your Minimum Viable Product (MVP). What's the absolute smallest version of your product that still solves a real problem for your target user? Write it down. Be specific. For example, if you're building a project management tool, the MVP might be: "Users can create a project, add tasks to it, & mark them as complete." That's it. No fancy integrations, no team features, just the core loop.

Choosing Your Tech Stack

This is where things can get overwhelming, but with Vibe Coding, we can keep it simple. The goal is to pick a stack that is well-supported by AI tools & easy to work with. A popular & effective stack for this approach is:

Frontend: A modern JavaScript framework like Nuxt.js (based on Vue.js) or Next.js (based on React). These are great because they have a lot of structure already built-in.
Backend: Node.js with a framework like NestJS. Using TypeScript on both the frontend & backend is a game-changer because you can share code (like validation rules) between them, which saves a lot of time.
Database: MongoDB is a fantastic choice for prototyping because it's flexible. You don't have to define a rigid structure upfront, which is perfect for an iterative, AI-driven process. Supabase is another excellent option, especially if you want something that's a bit more structured like a traditional database but still easy to work with.
Authentication: Don't try to build this yourself. Seriously. Services like Clerk make it incredibly easy to add user sign-up, login, & profile management to your app.
AI Engine: This is the star of the show! We'll be using Claude Code running in our terminal. You'll need to get it set up, but the documentation from Anthropic is pretty straightforward.

Day 1: Let's Build the Skeleton

Okay, planning is done. Let's get our hands dirty. Today is all about getting the basic structure of our application in place. This used to be a day of tedious setup & configuration, but with Claude Code, it's a conversation.

Project Setup

Open up your terminal. You're going to be talking to Claude Code a lot. Start by telling it what you want to do. Something like:

"Hey Claude, I want to set up a new project for a SaaS application. I'm going to use Nuxt.js for the frontend & NestJS for the backend. Can you create the initial project structure for me in a new folder called 'my-saas-app'?"

Claude Code will then ask you some questions & start creating the necessary files & folders. It can install the dependencies, set up the basic configuration files, & get everything ready for you. This is where Claude's ability to access your file system really shines.

Database Schema

Next, let's think about our data. For our project management MVP, we need 'projects' & 'tasks'. Let's tell Claude Code about this.

"Okay, I'm using MongoDB. I need two collections. The first is 'projects', which should have a 'name' (string), a 'description' (string), & a 'userId' (to know who owns it). The second is 'tasks', which should have a 'text' (string), a 'projectId' (to link it to a project), & a 'completed' (boolean) field."

Claude Code can then generate the necessary models & interfaces for your NestJS backend. You're not writing boilerplate code; you're just describing the structure of your data in plain English.

Connecting Frontend & Backend

Now, we need to make sure the frontend can talk to the backend. You can ask Claude Code to create a basic "health check" endpoint on the backend & a corresponding service on the frontend to call it.

"Can you create a simple '/api/health' endpoint in my NestJS backend that just returns a success message? Then, in my Nuxt.js app, create a service that calls this endpoint when the app loads & logs the message to the console."

By the end of Day 1, you'll have a fully configured, running project with a frontend that can communicate with a backend. This is HUGE. In the past, this alone could have taken a seasoned developer the better part of a day.

Day 2: Core Features & Making it Real with Users

Now that we have the skeleton, let's add some meat to the bones. Today, we're going to implement the core features of our MVP & add user authentication.

User Authentication with Clerk

First, let's get user management sorted. Head over to Clerk, create an account, & set up a new application. They'll give you some API keys. Now, back to Claude Code.

"I want to add Clerk for user authentication. Here are my API keys. Can you help me integrate it into my Nuxt.js app? I need sign-up, sign-in, & a basic user profile page."

Claude Code, combined with Clerk's documentation, can help you install the necessary packages & create the components for the authentication flow. This is a perfect example of vibe coding – you know what you want to achieve (user login), & you're using the AI to handle the how.

Building the Core CRUD Functionality

CRUD stands for Create, Read, Update, Delete. These are the basic operations for any data-driven app. Let's start with projects.

"Claude, I need to build the functionality for managing projects. On the backend, can you create the API endpoints for creating a new project, getting all of a user's projects, updating a project's name, & deleting a project? Make sure these are all protected so only the logged-in user can access their own projects."

Claude will get to work on the NestJS backend, creating the necessary controller, service, & data access logic. Then, you can move to the frontend.

"Now, on the frontend, let's build the UI for this. I need a page where a user can see a list of their projects. There should be a form to create a new project. Each project in the list should have an 'edit' & 'delete' button."

You'll likely go back & forth with Claude on this. Maybe you want the form to be in a popup modal. Maybe you want a confirmation before deleting. This is the "vibe" part. You refine the functionality through conversation. Once projects are done, you can repeat the process for tasks.

By the end of Day 2, you should have a working app where users can sign up, log in, create projects, & add tasks to them. It might not be pretty, but the core functionality is there.

Day 3: Making it Usable & Adding Some Polish

Our app works, but it probably looks pretty basic. Today is about improving the user experience (UX) & user interface (UI), & maybe adding a slightly more advanced feature.

Refining the UI/UX

This is where Vibe Coding really feels like magic. You can be very descriptive with your requests.

"Okay, the project list is pretty ugly. Let's style it. Can you make each project a card with a shadow? Let's use a nicer font, maybe from Google Fonts. Also, when I add a new project, I want it to animate in smoothly instead of just appearing."

You can even feed it inspiration. "I like how Trello's cards look, can we do something similar?" Claude Code can then generate the CSS or Tailwind CSS classes needed to style your components.

Adding a "Nice-to-Have" Feature

Let's say we want to add a simple search functionality.

"I want to add a search bar to the top of the projects page. As I type in it, it should filter the list of projects in real-time to only show the ones whose names match the search query."

This is a slightly more complex task, but it's still very achievable with this workflow. Claude Code can help you with the state management on the frontend to handle the filtering logic.

Thinking About Customer Communication

As you're building, it's a good time to think about how you'll communicate with your future customers. You're going to get questions, feature requests, & bug reports. While you're still small, you might handle these yourself, but it's smart to plan for automation.

This is where a tool like Arsturn comes in. You could eventually build an AI chatbot trained on your own documentation & FAQs. When a user has a question about how to use a feature, they can get an instant answer right on your site, 24/7. This frees you up to focus on building the product, not answering the same questions over & over. You can even use it to engage with website visitors & capture leads before they even sign up. It’s a great way to provide that initial support & engagement layer without needing a whole support team from day one.

By the end of Day 3, your app should not only be functional but also look & feel much more professional.

Day 4: Kicking the Tires & Getting it Live

We have a solid MVP. Now it's time to make sure it's not going to fall over & then push it out into the world.

Testing & Debugging with AI

Testing is one of the most common challenges in SaaS development. But it's CRUCIAL. A buggy product will kill your reputation before you even get started. The good news is, AI can help here too.

"Claude, can you write some tests for my backend project API? I want to make sure the 'create project' endpoint correctly saves a project to the database & that the 'delete project' endpoint actually removes it."

Claude Code can generate unit tests & integration tests for you. It's also an incredible debugging partner. If you get a weird error message, don't just stare at it for an hour. Paste the whole thing into Claude & ask:

"I'm getting this error when I try to create a task. Here's the error message & the code for my 'createTask' function. What's going on?"

Often, it can spot the issue in seconds. It's like having a senior developer you can ask for a quick code review at any time.

Deployment

Deployment can be another scary step, but again, let's just talk our way through it. Services like Vercel (for the frontend) & Render (for the backend) make this process much easier.

"I want to deploy my Nuxt.js frontend to Vercel & my NestJS backend to Render. I've never done this before. Can you walk me through the steps? What configuration files do I need to create?"

Claude Code can help you create the necessary

vercel.json

render.yaml

files, set up your environment variables (like your database connection string & Clerk API keys), & guide you through the process of connecting your GitHub repository to these services for continuous deployment.

By the end of Day 4, you should have a live, publicly accessible URL for your SaaS application. Take a moment to appreciate that. You just built & launched a SaaS product in four days. PRETTY COOL.

Day 5 & Beyond: The Real Work Begins

Getting to launch is a huge milestone, but it's not the finish line. In many ways, it's the starting line. The next phase is all about iteration, learning from your users, & growing.

Gathering User Feedback

You need to know what your users are thinking. Are they confused by a certain feature? Is there something they wish the app could do? You need to make it easy for them to tell you.

This is another area where a tool like Arsturn can be incredibly valuable. You can build a chatbot that proactively asks users for feedback. Imagine a little popup that appears after a user has created their third project & says, "Hey, it looks like you're getting the hang of things! Is there anything that would make creating projects even easier?" This is a fantastic, low-friction way to get insights you'd otherwise miss. Arsturn helps you build these no-code AI chatbots that can be trained on your data to have personalized, meaningful conversations with your users, helping you boost conversions & provide a better customer experience.

Iterating with Vibe Coding

The beauty of the Vibe Coding workflow is that it's built for rapid iteration. When you get a feature request, you don't have to dread a week of coding. You can jump back into your terminal & start a conversation with Claude Code. This allows you to respond to user feedback incredibly quickly, which is a massive competitive advantage.

Wrapping it up

So there you have it. A day-by-day guide to building your first SaaS application using the power of Vibe Coding & Claude Code. Turns out, you don't need to be a traditional coding genius to bring your ideas to life anymore. Your job as a founder is shifting from being a manual coder to being an architect & a guide. You're the one with the vision; tools like Claude are there to help you execute it.

This is a fundamental change in how software is made, & it’s opening the door for a whole new wave of builders & creators. It's not about replacing developers, but about augmenting them & empowering more people to build.

Hope this was helpful & gives you the confidence to finally start working on that SaaS idea you've been sitting on. Let me know what you think