Step by Step Guide to Building a lemlist API Integration in JS

Introduction

Hey there, fellow developer! Ready to supercharge your outreach game with lemlist's API? Let's dive in and build a slick integration that'll have you automating campaigns like a pro. We'll cover everything from basic setup to some nifty advanced features, so buckle up!

Prerequisites

Before we get our hands dirty, make sure you've got:

• Node.js and npm (you're probably way ahead of me on this one)
• A lemlist API key (if you don't have one, hop over to your lemlist account and grab it)
• Your HTTP request library of choice (Axios is my go-to, but fetch works great too)

Setting up the project

Let's kick things off:

mkdir lemlist-integration && cd lemlist-integration
npm init -y
npm install axios dotenv

Create a .env file for your API key:

LEMLIST_API_KEY=your_api_key_here

Authentication

Time to get that API key working for us. Create an api.js file:

require('dotenv').config();
const axios = require('axios');

const api = axios.create({
  baseURL: 'https://api.lemlist.com/api',
  headers: {
    'Authorization': `Bearer ${process.env.LEMLIST_API_KEY}`
  }
});

module.exports = api;

Basic API Requests

Let's fetch some campaigns and create a lead:

const api = require('./api');

// Get campaigns
async function getCampaigns() {
  try {
    const response = await api.get('/campaigns');
    console.log(response.data);
  } catch (error) {
    console.error('Error fetching campaigns:', error.response.data);
  }
}

// Create a lead
async function createLead(campaignId, leadData) {
  try {
    const response = await api.post(`/campaigns/${campaignId}/leads`, leadData);
    console.log('Lead created:', response.data);
  } catch (error) {
    console.error('Error creating lead:', error.response.data);
  }
}

getCampaigns();
createLead('campaign_id', { email: '[email protected]', firstName: 'John' });

Handling Responses

As you've seen, we're using try/catch blocks to handle errors gracefully. Always check error.response.data for detailed error messages from lemlist.

Advanced Features

Pagination

lemlist uses cursor-based pagination. Here's how to handle it:

async function getAllCampaigns() {
  let cursor = null;
  let allCampaigns = [];

  do {
    const response = await api.get('/campaigns', { params: { cursor } });
    allCampaigns = allCampaigns.concat(response.data.data);
    cursor = response.data.next;
  } while (cursor);

  return allCampaigns;
}

Filtering and Sorting

Many endpoints support filtering and sorting. For example:

api.get('/campaigns', {
  params: {
    sort: 'createdAt:desc',
    filter: 'status:active'
  }
});

Webhooks

lemlist can send webhooks for various events. Here's a quick Express server to handle them:

const express = require('express');
const app = express();

app.use(express.json());

app.post('/webhook', (req, res) => {
  const event = req.body;
  console.log('Received webhook:', event);
  // Process the event
  res.sendStatus(200);
});

app.listen(3000, () => console.log('Webhook server running on port 3000'));

Best Practices

• Respect rate limits: lemlist has rate limits, so implement exponential backoff for retries.
• Cache responses when appropriate to reduce API calls.
• Use environment variables for sensitive data like API keys.

Testing

Here's a quick Jest test to get you started:

jest.mock('./api');
const api = require('./api');

test('getCampaigns fetches campaigns successfully', async () => {
  api.get.mockResolvedValue({ data: [{ id: '1', name: 'Test Campaign' }] });
  const campaigns = await getCampaigns();
  expect(campaigns).toHaveLength(1);
  expect(campaigns[0].name).toBe('Test Campaign');
});

Conclusion

And there you have it! You're now armed with the knowledge to build a robust lemlist API integration. Remember, the API docs are your best friend for diving deeper into specific endpoints and features.

Now go forth and automate those campaigns like a boss! Happy coding! 🚀