Reading and Writing Data Using the Expensify API

Hey there, fellow JavaScript wizards! Ready to dive into the world of expense tracking with Expensify? Let's get our hands dirty with some code and explore how to sync data for a user-facing integration. Buckle up!

Authentication: Your Golden Ticket

First things first, we need to get cozy with Expensify's OAuth 2.0 flow. It's not as scary as it sounds, promise!

const getAccessToken = async (code) => {
  const response = await fetch('https://www.expensify.com/oauth2/token', {
    method: 'POST',
    headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
    body: new URLSearchParams({
      client_id: YOUR_CLIENT_ID,
      client_secret: YOUR_CLIENT_SECRET,
      code,
      grant_type: 'authorization_code',
    }),
  });
  return response.json();
};

Store that token safely, you'll need it for all your Expensify adventures!

Reading Data: Treasure Hunting

Time to fetch some expenses! Here's a quick way to grab a user's recent expenses:

const getExpenses = async (accessToken) => {
  const response = await fetch('https://integrations.expensify.com/Integration-Server/ExpensifyIntegrations', {
    method: 'POST',
    headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
    body: new URLSearchParams({
      requestJobDescription: JSON.stringify({
        type: 'get',
        credentials: { partnerUserID: accessToken },
        inputSettings: { type: 'expenses', startDate: '2023-01-01' },
      }),
    }),
  });
  return response.json();
};

Writing Data: Leave Your Mark

Creating a new expense is just as easy. Check this out:

const createExpense = async (accessToken, expenseData) => {
  const response = await fetch('https://integrations.expensify.com/Integration-Server/ExpensifyIntegrations', {
    method: 'POST',
    headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
    body: new URLSearchParams({
      requestJobDescription: JSON.stringify({
        type: 'create',
        credentials: { partnerUserID: accessToken },
        inputSettings: { type: 'expenses', employeeEmail: '[email protected]', transactionList: [expenseData] },
      }),
    }),
  });
  return response.json();
};

Syncing Strategies: Stay in the Loop

Webhooks are your best friend for real-time updates. Set them up like this:

app.post('/expensify-webhook', (req, res) => {
  const { type, id } = req.body;
  if (type === 'expense.created') {
    // Fetch and process the new expense
  }
  res.sendStatus(200);
});

Error Handling: Expect the Unexpected

Always wrap your API calls in try-catch blocks and handle those pesky errors:

try {
  const expenses = await getExpenses(accessToken);
  // Process expenses
} catch (error) {
  if (error.response && error.response.status === 401) {
    // Time to refresh that token!
  } else {
    console.error('Oops! Something went wrong:', error);
  }
}

Optimizing Performance: Speed Demon

Batch those requests when you can:

const batchRequests = async (accessToken, requests) => {
  const response = await fetch('https://integrations.expensify.com/Integration-Server/ExpensifyIntegrations', {
    method: 'POST',
    headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
    body: new URLSearchParams({
      requestJobDescription: JSON.stringify({
        type: 'batch',
        credentials: { partnerUserID: accessToken },
        inputSettings: { requests },
      }),
    }),
  });
  return response.json();
};

Security Considerations: Lock It Down

Never, ever expose your API keys in client-side code. Use environment variables and keep sensitive operations server-side:

const API_KEY = process.env.EXPENSIFY_API_KEY;

Testing and Debugging: Sandbox Fun

Use Expensify's sandbox environment for testing. It's like a playground, but for code!

const SANDBOX_URL = 'https://integrations.expensify-sandbox.com/Integration-Server/ExpensifyIntegrations';

Wrapping Up

And there you have it, folks! You're now armed with the knowledge to build a slick Expensify integration. Remember, the API is your oyster – so get out there and create something awesome!

Need more details? Check out the Expensify API docs for all the nitty-gritty. Happy coding!