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How to build Budgeting tool with Lovable?

Learn to build a robust budgeting tool with Lovable using our step-by-step guide. Create an intuitive, efficient finance solution for smarter budgeting.

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How to build Budgeting tool with Lovable?

 
Setting Up Your Lovable Project
 

  • Log into your Lovable account and create a new project named "Budgeting Tool".
  • Inside the project’s interface, you will see an option to create new files. We will create three new files: index.html, style.css, and app.js.
  • Since Lovable does not have a terminal, dependency management is done directly in the project by including libraries from CDNs in your HTML file.

 
Creating the HTML User Interface
 

  • Create a file named index.html in your project.
  • Paste the following code snippet into index.html to set up the basic UI for your budgeting tool:
    • 
<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Budgeting Tool</title>
    <link rel="stylesheet" href="style.css">
    <!-- Include any dependencies from a CDN if needed -->
    <script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/3.9.1/chart.min.js"></script>
  </head>
  <body>
    <header>
      <h1>Budgeting Tool</h1>
    </header>
    <main>
      <div id="inputSection">
        <label for="income">Monthly Income:</label>
        <input type="number" id="income" placeholder="Enter your income">
        <br>
        <label for="expense">Expense Description:</label>
        <input type="text" id="expense" placeholder="E.g. Rent">
        <br>
        <label for="amount">Expense Amount:</label>
        <input type="number" id="amount" placeholder="Enter expense amount">
        <br>
        <button id="addExpenseBtn">Add Expense</button>
      </div>
      <div id="summarySection">
        <p>Total Expenses: <span id="totalExpenses">0</span></p>
        <p>Remaining Budget: <span id="remainingBudget">0</span></p>
      </div>
      <canvas id="expenseChart" width="400" height="400"></canvas>
    </main>
    <script src="app.js"></script>
  </body>
</html>
  • This file sets up the input forms, display areas for expenses, and a canvas for the expense chart.

 
Adding CSS Styling
 

  • Create a new file named style.css in your Lovable project.
  • Copy and paste the following code snippet into style.css to style your budgeting tool’s interface:
    • 
body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 20px;
  background-color: #f4f4f4;
}


      header {
        text-align: center;
        margin-bottom: 20px;
      }
      

      #inputSection, #summarySection {
        background: #fff;
        padding: 15px;
        margin-bottom: 15px;
        border-radius: 5px;
        box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
      }
      

      label {
        display: block;
        margin-top: 10px;
      }
      

      input {
        width: 100%;
        padding: 8px;
        margin-top: 5px;
        box-sizing: border-box;
      }
      

      button {
        margin-top: 15px;
        padding: 10px 15px;
        background-color: #28a745;
        color: #fff;
        border: none;
        cursor: pointer;
        width: 100%;
      }
      

      button:hover {
        background-color: #218838;
      }



  • This styling will make your budgeting tool clean and user-friendly without needing external frameworks.

 
Implementing Budgeting Logic in JavaScript
 

  • Create a file named app.js in your Lovable project.
  • Paste the following code snippet into app.js to handle budgeting calculations and update the chart:
    • 
// Global variables to store expenses and income
let expenses = [];
let monthlyIncome = 0;


      // Function to update budget summary
      function updateBudget() {
        const totalExpenses = expenses.reduce((sum, expense) => sum + expense.amount, 0);
        const remainingBudget = monthlyIncome - totalExpenses;
      

        document.getElementById('totalExpenses').textContent = totalExpenses;
        document.getElementById('remainingBudget').textContent = remainingBudget;
      

        updateChart();
      }
      

      // Function to update chart using Chart.js
      let chart;  // Global chart variable
      function updateChart() {
        const ctx = document.getElementById('expenseChart').getContext('2d');
      

        // Prepare data for the chart
        const labels = expenses.map(expense => expense.description);
        const data = expenses.map(expense => expense.amount);
      

        if (chart) {
          chart.data.labels = labels;
          chart.data.datasets[0].data = data;
          chart.update();
        } else {
          chart = new Chart(ctx, {
            type: 'pie',
            data: {
              labels: labels,
              datasets: [{
                label: 'Expenses',
                data: data,
                backgroundColor: [
                  '#f44336',
                  '#9c27b0',
                  '#2196f3',
                  '#4caf50',
                  '#ff9800'
                ]
              }]
            },
            options: {
              responsive: true
            }
          });
        }
      }
      

      // Event listener for adding expenses
      document.getElementById('addExpenseBtn').addEventListener('click', function() {
        // Read and update the monthly income
        const incomeInput = document.getElementById('income').value;
        monthlyIncome = parseFloat(incomeInput) || 0;
      

        // Read expense description and amount
        const description = document.getElementById('expense').value;
        const amountInput = document.getElementById('amount').value;
        const amount = parseFloat(amountInput);
      

        if (description && amount) {
          expenses.push({ description: description, amount: amount });
          updateBudget();
          // Clear the expense inputs
          document.getElementById('expense').value = '';
          document.getElementById('amount').value = '';
        } else {
          alert('Please enter both a description and a valid amount for the expense.');
        }
      });



  • This script defines a function to calculate total expenses and remaining budget, then updates both the HTML elements and the chart created using Chart.js.

 
Testing Your Budgeting Tool
 

  • Click on the "Run" or "Preview" button in Lovable to load your project in the browser.
  • Enter your monthly income, add several expenses, and observe the dynamic updates in the summary and the pie chart.
  • If needed, adjust the HTML, CSS, or JavaScript code directly in Lovable’s editor to fit your requirements.

 
Deploying and Sharing Your Budgeting Tool
 

  • Once your tool is working as expected, use Lovable’s sharing options to publish your project.
  • You can share the URL provided by Lovable with others so they can use your budgeting tool directly from their browsers.
  • Any time you edit and save your files, your changes will be reflected once you refresh the published version.

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How to build your budgeting API with Express, Mongoose, and Lovable

const express = require('express');
const router = express.Router();
const mongoose = require('mongoose');

const BudgetSchema = new mongoose.Schema({
  userId: { type: mongoose.Schema.Types.ObjectId, required: true, ref: 'User' },
  month: { type: String, required: true },
  categories: [{
    name: { type: String, required: true },
    limit: { type: Number, required: true },
    spent: { type: Number, default: 0 }
  }],
  expenses: [{
    description: { type: String, required: true },
    category: { type: String, required: true },
    amount: { type: Number, required: true },
    date: { type: Date, default: Date.now }
  }]
});
const Budget = mongoose.model('Budget', BudgetSchema);

router.post('/api/budget', async (req, res) => {
  try {
    const { userId, month, categories } = req.body;
    const budget = new Budget({ userId, month, categories });
    await budget.save();
    res.status(201).json({ success: true, data: budget });
  } catch (error) {
    res.status(500).json({ success: false, error: error.message });
  }
});

router.post('/api/budget/:id/expense', async (req, res) => {
  try {
    const { description, category, amount } = req.body;
    const budget = await Budget.findById(req.params.id);
    if (!budget) {
      return res.status(404).json({ success: false, message: 'Budget not found' });
    }
    
    budget.expenses.push({ description, category, amount });
    
    const catIndex = budget.categories.findIndex(cat => cat.name === category);
    if (catIndex !== -1) {
      budget.categories[catIndex].spent += amount;
    }
    
    await budget.save();
    res.status(200).json({ success: true, data: budget });
  } catch (error) {
    res.status(500).json({ success: false, error: error.message });
  }
});

module.exports = router;

How to implement currency conversion for expenses in your Lovable budgeting tool


"use strict";

const express = require('express');
const axios = require('axios');
const router = express.Router();
const Budget = require('../models/Budget');

// External API endpoint for currency conversion (using USD as base)
const EXCHANGE_RATE_API\_URL = 'https://api.exchangerate-api.com/v4/latest/USD';

router.post('/api/budget/:budgetId/expense/convert', async (req, res) => {
  try {
    const { description, category, amount, currency } = req.body; // 'amount' is in the provided currency
    const budgetId = req.params.budgetId;

    // Fetch exchange rates from the external API
    const response = await axios.get(EXCHANGE_RATE_API\_URL);
    const rates = response.data.rates;
    if (!rates[currency]) {
      return res.status(400).json({ error: 'Currency not supported' });
    }

    // Convert the provided amount to USD
    const conversionRate = rates[currency];
    const amountInUSD = amount / conversionRate;

    // Find the corresponding Budget document
    const budget = await Budget.findById(budgetId);
    if (!budget) {
      return res.status(404).json({ error: 'Budget not found' });
    }

    // Build a new expense record with conversion details
    const expense = {
      description,
      category,
      originalAmount: amount,
      originalCurrency: currency,
      amountInUSD,
      date: new Date()
    };
    budget.expenses.push(expense);

    // Update the spending in the corresponding category if exists
    const catIndex = budget.categories.findIndex(cat => cat.name === category);
    if (catIndex !== -1) {
      budget.categories[catIndex].spent += amountInUSD;
    }

    await budget.save();
    res.status(200).json({ success: true, data: budget });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

module.exports = router;

How to Build a Budget Reconciliation API Endpoint with Lovable


const express = require('express');
const router = express.Router();
const Budget = require('../models/Budget');

// Endpoint to reconcile monthly budget and generate spending insights per category
router.get('/api/budget/:budgetId/reconcile', async (req, res) => {
  try {
    const { budgetId } = req.params;
    const budget = await Budget.findById(budgetId);
    if (!budget) {
      return res.status(404).json({ success: false, message: 'Budget not found' });
    }

    // Compute total spent and per-category spending
    let totalSpent = 0;
    const insights = budget.categories.map(category => {
      const catExpenses = budget.expenses.filter(exp => exp.category === category.name);
      const spent = catExpenses.reduce((sum, exp) => sum + exp.amount, 0);
      totalSpent += spent;
      let advice = 'On track';
      if (spent > category.limit) {
        advice = 'Over budget! Consider trimming expenses or increasing the limit.';
      } else if (spent < category.limit \* 0.5) {
        advice = 'Below half of the limit. You might reallocate extra funds if needed.';
      }
      return {
        category: category.name,
        limit: category.limit,
        spent,
        advice
      };
    });

    // Overall budget health insight
    const overallAdvice = totalSpent > budget.categories.reduce((sum, cat) => sum + cat.limit, 0)
      ? 'Total spending exceeds planned limits.'
      : 'Spending is within the overall budget.';

    res.status(200).json({
      success: true,
      totalSpent,
      insights,
      overallAdvice
    });
  } catch (error) {
    res.status(500).json({ success: false, error: error.message });
  }
});

module.exports = router;

Want to explore opportunities to work with us?

Connect with our team to unlock the full potential of no-code solutions with a no-commitment consultation!

Book a Free Consultation
Matt Graham, CEO of Rapid Developers

Book a call with an Expert

Starting a new venture? Need to upgrade your web app? RapidDev builds application with your growth in mind.

Book a free No-Code consultation

Best Practices for Building a Budgeting tool with AI Code Generators

 
Introduction and Overview
 

Building a budgeting tool enhanced with AI code generators involves combining traditional software development practices with innovative AI-powered coding assistance. This guide provides a detailed workflow for non-tech users to understand and implement best practices while benefiting from AI code generation capabilities.

 
Prerequisites
 

  • An account with an AI code generator platform (e.g., GitHub Copilot, OpenAI Codex, or similar).
  • Basic understanding of budgeting concepts and requirements (income, expenses, savings, etc.).
  • A simple plan or mockup for your budgeting tool’s user interface and functionality.
  • A willingness to experiment and iterate over the initial design.

 
Understanding Your Budgeting Tool Requirements
 

  • Define the main functionalities:
    • Expense and income tracking.
    • Budget categorization (e.g., food, rent, utilities, entertainment).
    • Reporting and visualization of financial data.
    • Integration with bank accounts or manual data entry.
  • Identify the target audience and their needs to ensure your design is user-friendly.
  • Outline the type of data inputs and expected outputs to streamline development.

 
Designing Your Budgeting Tool Architecture
 

  • Decide on the overall structure:
    • The frontend interface where users interact with the tool.
    • The backend logic that processes data and applies budgeting formulas.
    • Database or storage mechanism for saving user data.
  • Create simple diagrams or sketches to visualize the data flow and interactions.
  • Plan integrations with third-party services (if needed) for enhanced functionality.

 
Using AI Code Generators for Code Assistance
 

  • Integrate an AI code generation tool into your development environment. The AI can help by auto-completing code, suggesting functions, or generating boilerplate code.
  • When using AI prompts, be specific in your instructions. For example, you can instruct the AI to generate a function for calculating the total budget: 
    
def calculate\_total(expenses, incomes):
    """
    Calculate the net budget based on expenses and incomes.
    :param expenses: list of expense amounts
    :param incomes: list of income amounts
    :return: net budget remaining
    """
    total\_expenses = sum(expenses)
    total\_incomes = sum(incomes)
    return total_incomes - total_expenses
  • Review and edit the AI-generated code to ensure it meets your requirements and follows best coding practices.
  • Leverage the tool’s suggestions to optimize performance and readability.

 
Implementing the Budgeting Logic
 

  • Develop functions to handle:
    • Data input and validation.
    • Calculation of totals and categorization of spending.
    • Generation of summary reports and charts.
  • Use AI generators to create sample code blocks for repetitive tasks, ensuring you understand each generated snippet.
  • For example, you might create a function to validate expense entries: 
    
def validate\_entry(entry):
    """
    Validate that an entry contains proper data values.
    :param entry

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