Build an application with 500 active users using DigitalOcean

Introduction

You know that feeling when you randomly think of an idea (probably in the middle of the night), and you feel it could be a big hit? Well, I had a similar thought, built Nomado.live in a week, and you can see the results below:

P.S. - Nomado is a travel app that gives travellers information about visas, gives them personalized itinerary and has a community where travellers can drop genuine reviews.

Nothing makes a developer happier than having users for their apps. In this article, I will share some tips to help you build better and scalable apps. My manager often says, “If your idea worked well once, see how you can improve it.” Therefore, we need to ensure our apps have a solid architecture. I will also show you how I built Nomado using just a few services from DigitalOcean and several APIs. You don’t need to over-engineer any application to make it usable and provide a good experience.

To-do before you start building

Building apps is the most exciting part of having an idea. You are excited about the tech stack you will be using and all the fancy features that you want to add. But you need to take a step back here and think about these things first:

• The use case you are solving - In my case, I wanted to build a travel app. The problem statement stemmed from my use case of having visa-related issues. I didn’t think of catering to 500 users while building the app; I thought about one user (me) and the use case that I wanted to solve for myself. Then I recalled conversations that I had with some of my friends who love to travel and the issues they face (real reviews and itineraries), so I prioritized three features and then moved to how I wanted to build it.

• The application flow - Choose any tool of your choice (Excalidraw in my case), and chart out a basic flow/structure of how you want your application to look. What you see below is the first version of Nomado that I drew, and then there’s the final version now. It looks different, but the features are the same. This helped me have a design in mind and proceed step by step, later improving the experience and the design language.

• Tech-stack you will be using - Even in tech, the proverb “too many cooks will spoil the broth” is true, and more often, the solution lies in simplicity. You need to think of the main building blocks you have and the tech-stack that can help you solve it, without pinching a hole in your pocket. For example, for Nomado, I chose Next.js for the frontend since I am more comfortable with it, and then chose DigitalOcean for database, hosting, and GenAI features since it is simple to use and pocket-friendly.

Once you have fixed all of these, you then move to building the application.

How I built Nomado

Before we get into the details of “how”, let’s learn a little bit of “why” I built Nomado - I travel a lot, and my main issue is with visas (the lengthy processes, the time taken for research, and juggling between poorly made embassy websites). I needed an application that gives me all the visa-related details I need, along with an itinerary that is actually good and tells me all the must-haves, like the apps to install and things to pack, etc. Another problem is that I have been to Instagram-famous places (thanks to social media) and had a bad experience, so I wanted real feedback about places from real people. What better way to do this than by having a community section (my inner DevRel kicked in while building this)?

This is what the overall architecture of Nomado looks like:

Now let’s cover how I built the fundamentals of Nomado, and this is something that you can replicate in any application that you are building.

P.S. - The code is open source, so you can find everything on GitHub.

Building and integrating an AI agent in the application

In Nomado, the GenAI agent is helping us with the itinerary and important tips, as shown in the image below.

The flow of the agent is pretty straightforward:

• You tell Nomado where you’re going, for how long, and when.
• The app sends this information to a GenAI agent I built on DigitalOcean.
• The agent uses Llama 3.3 Instruct to create a personalized travel plan.
• You receive an itinerary with everything you need to know.

The diagram below explains exactly how the GenAI agent is working and providing us with the details:

To have a similar agentic workflow in your application, follow the steps below:

Building your own GenAI Agent on DigitalOcean

To create a GenAI agent similar to Nomado’s, you’ll need to:

• Log into DigitalOcean and navigate to the GenAI platform.
• Create and configure your agent with the Llama 3.3 Instruct model.
• Set up your knowledge base (if needed).

For detailed step-by-step instructions on setting up your GenAI agent, follow this guide.

Once your agent is set up, let’s integrate it with your application.

Integrating with your application

To integrate the agent with your application:

• Set up environment variables:

  SECURE_AGENT_KEY=your_agent_key
  AGENT_BASE_URL=your_agent_base_url
  

• Initialize the OpenAI SDK:

  client = new OpenAI({  apiKey: SECURE_AGENT_KEY,  baseURL: AGENT_BASE_URL,});
  

• Create your prompt structure:

  const prompt = Your prompt;
  

• Make the API call:

  response = await client.chat.completions.create({  model: "Llama 3.3 Instruct",  messages: [    {      role: "system",      content: "You are an assistant...",    },    { role: "user", content: prompt },  ],  temperature: 0.7,  max_tokens: 2000,});
  

Creating and integrating a database

Nomado has a community section where travellers can add reviews/feedback of the countries they have visited.

I have used Postgres as a database for this, and that’s typically because:

• It’s reliable for handling complex data relationships.
• It’s a great choice for adding AI capabilities later, as it has strong support for vector operations and can be easily integrated with AI tools.

Remember: Our aim is to make our application scalable, so this is a great step towards it.

Setting up on DigitalOcean

Setting up a database on DigitalOcean is straightforward:

1. Log in to DigitalOcean and navigate to the Databases section.
2. Click “Create Database” and select PostgreSQL as the engine.
3. Choose a region close to your target users for better performance.
   
4. Select a basic $15 plan for development (you can scale up later as needed).
5. Then click “Create Database Cluster” to create the database.

Once the database is provisioned, you will get the following details which are needed to establish the connection:

• Host URL
• Port number
• Database password
• Connection details

Connecting the DigitalOcean Database

To connect the database to your application (Next.js in this example), you need to create a simple database utility that handles connections and queries.

Here’s how it works:

• First, set up your environment variables:

POSTGRES_HOST=your_host_url
POSTGRES_PORT=your_port
POSTGRES_USER=your_username
POSTGRES_PASSWORD=your_password
POSTGRES_DATABASE=your_database_name

• Create a database connection pool:

import { Pool } from "pg"
const pool = new Pool({
  connectionString: process.env.DATABASE_URL,
  ssl: { rejectUnauthorized: false }
})

• Create your database tables. For Nomado’s community section, we use a simple schema:

CREATE TABLE experiences (
  id SERIAL PRIMARY KEY,
  country VARCHAR(100) NOT NULL,
  experience TEXT NOT NULL,
  user_name VARCHAR(100) NOT NULL,
  created_at TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP
)

• Use the database in your application. For example, to add a new travel experience:

async function addExperience(country: string, experience: string, userName: string) {
  const result = await pool.query(
    "INSERT INTO experiences (country, experience, user_name) VALUES ($1, $2, $3) RETURNING *",
    [country, experience, userName]
  )
  return result.rows[0]
}

The beauty of using Postgres with Next.js is that you can easily add more features later. For example, we added content moderation by simply adding a new column to our table:

ALTER TABLE experiences 
ADD COLUMN moderation_passed BOOLEAN DEFAULT FALSE

This setup gives us a solid foundation for building more features while keeping our code clean and maintainable. Plus, with DigitalOcean’s managed database, we don’t have to worry about database maintenance or backups - it’s all handled for us.

Hosting it and mapping it to a custom domain

Once your application has some structure to it, and you want to test it on production, you should consider hosting it. This too can be done in DigitalOcean using the App Platform.

Since our code is already on GitHub, we will be using it to deploy the app using the following steps:

1. Deploy using GitHub

   • Go to the Apps page and click “Create App”.
   • Connect your GitHub account and select the repository.
   • In the source directory field, specify the directory your code is in( /frontend in our case)
   • Enable auto-deploy for automatic updates when you push changes

2. Configure resources

   • Choose the appropriate plan for your needs.
   • Review the configuration and click “Create Resource”
   • Set up environment variables.

POSTGRES_HOST=your_db_host
POSTGRES_PORT=your_db_port
POSTGRES_USER=your_db_user
POSTGRES_PASSWORD=your_db_password
POSTGRES_DATABASE=your_db_name
SECURE_AGENT_KEY=your_genai_key
AGENT_BASE_URL=your_genai_url

• If any new environment variables needs to be added, so you can do so from the Settings page as shown below:

• Once the deployment is complete, your app will be hosted on a URL like https://your-app-name.ondigitalocean.app.

• Mapping to custom domain once your app is deployed:

  A custom domain is not only easier to remember, but it also helps with SEO. If you have a domain purchased (from any provider of your choice), you can map it from the control panel itself by following the steps mentioned in this tutorial.
  Now your application is live with:

  • A managed database
  • Automatic deployments
  • Custom domain
  • Scalable infrastructure

The best part is that you can focus on building features while DigitalOcean handles the infrastructure. When you push changes to GitHub, they’re automatically deployed to your production environment.

Ending notes

Building Nomado taught me a lot about building scalable applications without overcomplicating things.

Here are some key takeaways if you would like to build something similar:

1. Start small, think big
   • Begin with a clear problem you want to solve
   • Don’t try to build everything at once
   • Focus on core features that provide immediate value
2. Choose the right tools
   • Pick technologies you’re comfortable with
   • Use managed services when possible (like DigitalOcean’s App Platform)
   • Don’t be afraid to mix and match services that work best for your needs
3. Community Matters
   • Share your work early (like I did on social media)
   • Get feedback from real users
   • Be open to suggestions and improvements
4. Keep learning. DigitalOcean has some amazing resources that helped me along the way:
   • DigitalOcean App Platform documentation
   • PostgreSQL best practices
   • Community tutorials on various topics

P.S. - If you’re interested in seeing how Nomado works under the hood, check out the open-source code on GitHub. Feel free to use it as a reference for your own projects!