Building AI Apps in 2025: A Deep Dive into Replit, Cursor, & OpenAI Workflows
Z
Zack Saadioui
8/11/2025
Title: Building AI Apps in 2025: A Deep Dive into Replit, Cursor, & OpenAI Workflows
What's up, everyone? It feels like we're living in a completely different world than we were just a couple of years ago. The AI boom hasn't just been a buzzword; it's fundamentally changing how we, as developers, builders, & creators, bring ideas to life. The days of painstakingly scaffolding every single file & writing boilerplate code from scratch are… well, they're not gone, but they're definitely on the ropes.
Today, we have a new class of tools that are less like simple IDEs & more like development partners. They can understand plain English, generate entire codebases, & help us build things faster than ever before. It's a wild time to be in tech.
But with all these new tools popping up, the big question is: which one should you actually use? Honestly, it's confusing. You've got Replit, Cursor, & of course, the classic approach of using the OpenAI API directly. They all promise to help you build with AI, but they go about it in VERY different ways.
I've been spending a ton of time in the trenches with these tools, trying to figure out the real-world workflow for each. So, I figured I'd break it down for you. We're going to go deep on how you actually build with each of them, who they're for, & the pros & cons you'll run into along the way.
Hope this is helpful!
The State of AI in Development: A Quick Reality Check
Before we jump into the tools, let's just acknowledge how seismic this shift is. We're not talking about a minor trend here. Statistics show that by 2025, a massive 82% of developers are expected to be using AI-assisted coding tools. It’s becoming the industry standard. Over half of all developers will be regularly relying on generative AI for their work.
This isn't just about making developers faster, though it certainly does that. Some reports show productivity boosts of 20-50% or even more. It’s about changing the very nature of development. It’s allowing non-technical founders to prototype ideas & experienced devs to focus more on architecture & complex logic instead of grunt work. This new style of development, sometimes called "vibe coding," is less about perfect syntax & more about articulating a vision.
But it also comes with new challenges. We have to be more vigilant about the code these AIs generate. Are there security flaws? Is it based on outdated practices? The human developer is more important than ever, not as a simple coder, but as a reviewer, a guide, & a critical thinker.
With that context, let's get into the nitty-gritty of the tools themselves.
Replit: The All-in-One "Idea-to-App" Machine
First up is Replit. If you've seen those mind-blowing videos of someone typing a sentence & getting a fully functional web app a few minutes later, they were probably using Replit.
The Gist: Replit is a browser-based, all-in-one development environment. You don't need to install anything on your computer. You just open your web browser, sign in, & you can start coding. Its secret weapon is the Replit Agent, an AI that acts like a project manager & developer rolled into one.
The Replit Workflow: From Prompt to Deployed App
Building with Replit is a unique experience. It’s probably the closest we've gotten to just "speaking" an app into existence. Here's what the workflow typically looks like:
The Initial Prompt: You start not by creating a file, but by talking to the Replit Agent. You describe the app you want to build in plain English. For example, you might say: "Build me a simple blogging platform where I can write, edit, & delete posts. It should have a clean, minimalist design & use a simple database to store the posts."
The AI's Plan: The Replit Agent doesn't just start spitting out code. First, it thinks. It will come back to you with a plan. This plan will outline the features it's going to build, the tech stack it's chosen (often Python with Flask or a Node.js setup), & sometimes even suggest additional features. You get to review this plan & approve it before it writes a single line of code.
Autonomous Code Generation: Once you approve the plan, the agent gets to work. This is the magic part. You'll see files appearing in your workspace:
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index.html
,
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style.css
,
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app.py
, database files, etc. The AI is autonomously creating the entire project structure. It writes the HTML for the front end, the Python code for the backend logic, & the database integration.
Iterative Refinement via Chat: The first version is rarely perfect. Maybe the design is a bit off, or a feature is missing. You don't dive into the code (though you can). Instead, you just keep talking to the agent. "Can you make the background color a light grey?" or "Add a feature that counts the words in each post." The agent will then go back & modify the files to incorporate your feedback.
One-Click Deployment: Because Replit is a cloud environment, your app is essentially ready to go live from the start. With a click of a button, you can deploy your application & get a public URL to share with the world.
Who is Replit For?
Replit is, hands down, the best option for beginners, non-technical founders, & anyone who wants to go from an idea to a working prototype as fast as humanly (or AI-ly) possible. Its browser-based nature makes it incredibly accessible for classrooms & collaborative projects.
The Upside:
Insanely Fast Prototyping: Nothing beats it for speed from idea to a shareable link.
Zero Setup: You can start building on any device with a web browser.
Beginner-Friendly: It abstracts away a lot of the complex setup that can frustrate newcomers.
The Downside:
Less Control: The AI makes a lot of decisions for you. If you're an experienced developer who wants to use a specific framework or library, it can feel a bit restrictive.
Vendor Lock-in: Replit makes it SUPER easy to use its built-in database & deployment. Moving your app to another hosting provider later can be a bit tricky.
Potential for Messy Code: Sometimes, the AI's solutions can be a bit convoluted. If you have to manually edit the code later, it can be a bit of a treasure hunt.
Cursor: The AI-Powered Scalpel for Professional Developers
Now, let's switch gears completely & talk about Cursor. If Replit is a magic wand that builds the whole castle for you, Cursor is like an AI-powered exoskeleton for a master craftsman.
The Gist: Cursor is a desktop application that’s a fork of VS Code. This means it looks & feels almost exactly like the most popular code editor in the world, but with AI superpowers baked directly into its core. You work on files on your own computer, giving you full control over your environment.
The Cursor Workflow: A Coder's Co-Pilot
The workflow in Cursor feels much more like traditional development, but accelerated at every step. It’s not about generating an entire app from one prompt; it’s about a continuous, AI-assisted conversation with your codebase.
Local Project Setup: You start by opening a folder on your computer, just like you would with VS Code. You are in complete control of your file structure, your choice of framework (Next.js, Django, etc.), & your version control with Git.
Context is King: Before you start, you can give Cursor context. You can create a
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docs/structure.md
file to outline your project's goals, or use the "Rules" feature to tell the AI what technologies & coding styles to use. This is a key difference: you're guiding the AI from the outset.
File-by-File Generation & Refinement: You'll use the integrated chat panel to work on your app. You might start by saying, "@new file
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components/BlogPost.js
Create a React component that displays a blog post with a title, content, & author." Cursor will generate that single file.
The "With Code" & "Ask" Modes: This is where Cursor really shines. You can highlight a block of code & ask the AI to "refactor this to use async/await" or "find the bug in this function." The AI has a deep understanding of your entire codebase, so it can make changes across multiple files while being aware of dependencies. This is something Replit struggles with.
Granular Control & Diffing: When Cursor suggests a change, it doesn't just overwrite your code. It presents you with a "diff" view, showing you exactly what it wants to add or remove. You can accept or reject these changes piece by piece. This level of control is CRUCIAL for professional developers who need to maintain code quality.
Terminal Integration: You'll still use the terminal to install dependencies (
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npm install
), run your development server, & commit to Git. The AI can even run these terminal commands for you if you ask it to.
Who is Cursor For?
Cursor is built for experienced developers who are comfortable in a traditional coding environment like VS Code but want to supercharge their workflow. It’s for people working on large, complex projects where code quality, refactoring, & deep codebase understanding are paramount.
The Upside:
Total Control & Flexibility: You control the tech stack, the file structure, & every single change the AI makes.
Deep Codebase Awareness: Its ability to analyze your entire project makes it incredible for complex refactoring & bug fixing.
Seamless Integration: It fits right into an existing, professional development workflow without forcing you to change how you work.
The Downside:
Steeper Learning Curve: It assumes you have a certain level of technical knowledge. You need to know how to set up a project, use the terminal, & manage dependencies.
Not an "All-in-One" Solution: Cursor helps you write the code, but you're still responsible for your own database, deployment, & hosting.
The OpenAI API: The "Build-It-Yourself" Bedrock
Finally, we have the most fundamental approach: using the OpenAI API directly. This isn't an AI coding assistant in the same way as Replit or Cursor. It's the raw material.
The Gist: With this method, you are a traditional developer building an application from scratch. You write all the code for your app's structure, UI, & backend logic yourself. Then, you make specific API calls to OpenAI's models (like GPT-4o) to add intelligent features to your app.
The OpenAI API Workflow: The Developer in Command
This workflow is 100% manual, with AI sprinkled in where you decide it's needed.
Build Your Application: First, you build your app. Let's stick with our blog example. You'd create the frontend in React or Vue, the backend in Node.js or Python, & set up your database. This is all standard development work.
Get Your API Key: You sign up on the OpenAI platform & get an API key. This key is your secret credential to access their powerful models. You need to manage this key securely.
Identify AI Integration Points: You decide where AI can enhance your app. For a blog, you might want to:
Generate blog post ideas.
Create a summary of a long post.
Write a social media post to promote the article.
Power a chatbot that can answer questions about your blog posts.
Make the API Call: In your backend code, you'll use an OpenAI SDK (for Python, Node.js, etc.) to make a call to the API. You'll construct a prompt, send it to the model, & receive a response (usually in JSON format).
Process & Display the Response: You then take the AI's response & integrate it into your app's frontend. For example, you'd display the generated blog post ideas in a list for the user to choose from.
Who is the OpenAI API For?
This approach is for developers who want maximum control & want to build truly custom AI features that aren't possible with off-the-shelf assistants. You're not just building an app with AI; you're building an AI feature.
This is also where solutions for specific business needs come into play. For instance, if you wanted to add a sophisticated customer service component to your app, building a chatbot from scratch using the OpenAI API is complex. That's where a platform like Arsturn becomes incredibly valuable. It allows businesses to create custom AI chatbots trained on their own data. So, instead of you, the developer, having to manage the entire conversational AI pipeline, Arsturn handles it, providing instant, 24/7 customer support & engagement. This frees you up to focus on your core application logic, while still leveraging powerful, custom AI for business communication.
The Upside:
Unlimited Flexibility: You can build any AI feature you can imagine, in any way you want.
Full Ownership: You own the entire application & user experience from top to bottom.
The Downside:
Most Labor-Intensive: You're responsible for everything – the app, the UI, the backend, the API integration, & error handling.
Requires Strong Coding Skills: This is not for beginners. You need to be a competent developer to use the API effectively.
So, Which Workflow is Right for You? A Head-to-Head Comparison
Feature
Replit
Cursor
OpenAI API
Ideal User
Beginners, non-coders, quick prototypers
Experienced developers, VS Code users
Professional developers building custom AI features
Environment
Browser-based, cloud IDE
Local desktop app (VS Code fork)
Your own local or cloud environment
Core Workflow
Prompt -> AI Plan -> AI Build -> Iterate
Code -> AI Assist -> Refactor -> Commit
Build App -> Identify AI need -> Call API -> Integrate
Control
Low (AI makes most decisions)
High (Developer has final say on all changes)
Absolute (You write all the code)
Speed
Fastest for initial prototype
Fast for development cycles
Slowest initial setup, fast for adding features
Use Case
Building entire simple apps from an idea.
Augmenting existing, complex development.
Adding specific, custom AI capabilities to an app.
The Future is Collaborative
Here’s the thing: we're moving away from the idea of a developer working in isolation. The future of coding is collaborative, & your most active collaborator might just be an AI. These tools aren't here to replace developers. If anything, they're making good developers even better by automating the tedious parts of the job.
But it's crucial to remember that these are tools, not magic boxes. The code they generate can have errors, security vulnerabilities, or just be inefficient. The developer's role is shifting from a writer of code to an editor & director of code. Your critical thinking & expertise are more valuable than ever.
And as businesses look to integrate AI more deeply, especially for customer-facing roles, the need for specialized solutions will grow. While a developer can build a proof-of-concept chatbot, a robust, scalable business solution is a different beast. For that, leveraging a conversational AI platform like Arsturn is the smart move. It helps businesses build those meaningful connections with their audience through personalized, no-code AI chatbots, boosting conversions & optimizing the customer experience without adding a massive development burden.
Ultimately, the choice between Replit, Cursor, & the OpenAI API comes down to your personal workflow, your skill level, & what you're trying to build.
Want to turn an idea into a live app by this afternoon? Go with Replit.
Are you a professional developer looking to 10x your productivity in your existing workflow? Download Cursor.
Are you building a unique application & need to add a very specific, custom AI feature? Use the OpenAI API.
The best part is, you don't have to choose just one. A common workflow is to prototype an idea in Replit, then download the code & continue to refine it in Cursor for a more robust build-out.
It's an exciting new landscape, that's for sure. The best thing you can do is jump in & start building.
Let me know what you think in the comments. What's your experience been like with these tools? Hope this was helpful