Lovable and CoStar integration: Step-by-Step Guide 2025

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How to integrate Lovable with CoStar?

Setting Up CoStar Configuration

Create a new TypeScript file named costarConfig.ts in your project’s source folder.
Insert the following code snippet into costarConfig.ts. This file will store your CoStar API key and endpoint. Replace YOURAPIKEY with your actual API key.


export const COSTARAPIKEY = 'YOURAPI_KEY';
export const COSTARENDPOINT = 'https://api.costar.com/v1';

Creating the CoStar Integration Module

Create another new TypeScript file named costarIntegration.ts in the same source folder.
Copy and paste the following code into costarIntegration.ts. This module imports the configuration values and defines an asynchronous function that fetches property data from CoStar using the fetch API.


import { COSTARAPIKEY, COSTAR_ENDPOINT } from './costarConfig';

export async function fetchPropertyData(propertyId: string): Promise<any> {
  const url = ${CO_STAR_ENDPOINT}/properties/${propertyId}?api_key=${CO_STAR_API_KEY};
  try {
    const response = await fetch(url);
    if (!response.ok) {
      throw new Error('Network response was not ok');
    }
    return await response.json();
  } catch (error) {
    console.error('Failed to fetch CoStar property data:', error);
    throw error;
  }
}

Integrating CoStar Module with Your Lovable Code

Locate your project’s main TypeScript file (for instance, app.ts or lovable.ts).
At the top of this file, import the integration function from costarIntegration.ts by adding the following import statement.
Then, insert the code that calls the integration function. This example demonstrates fetching property data and logging the result.


import { fetchPropertyData } from './costarIntegration';

async function integrateCoStar() {
  try {
    const propertyData = await fetchPropertyData('12345');
    console.log('CoStar property data:', propertyData);
  } catch (error) {
    console.error('CoStar integration error:', error);
  }
}

// Call this function when your application initializes or when appropriate.
integrateCoStar();

Adding a Fetch Polyfill

If your Lovable project environment does not support the fetch API by default, you must add a polyfill.
Since Lovable does not have a terminal for installing dependencies, open your project’s main HTML file (for example, index.html).
Add the following script tag inside the <head> or before the closing </body> tag to load the fetch polyfill from a CDN.


<script src="https://cdnjs.cloudflare.com/ajax/libs/fetch/3.6.2/fetch.min.js"></script>

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