How to build a public Calendly integration: Building the Auth Flow

Jul 31, 2024 • 8 minute read

Hey there, fellow JavaScript aficionado! Ready to dive into the world of Calendly integrations? Let's roll up our sleeves and build an auth flow that'll make your users say, "Wow, that was smooth!"

Introduction

Calendly's API is a powerhouse for scheduling automation, and we're about to harness that power. But first things first: we need to nail the authorization flow. It's the gatekeeper of your integration, so let's make it rock-solid and user-friendly.

Prerequisites

Before we jump in, make sure you've:

Set up your Calendly developer account (it's a breeze, trust me)
Snagged your API credentials (Client ID and Client Secret)

Got 'em? Great! Let's get this party started.

Understanding Calendly's OAuth 2.0 Flow

Calendly uses OAuth 2.0 with the authorization code grant type. It's like a secret handshake between your app and Calendly. Here's the gist:

Your app asks for permission
User says "Yes, please!"
Calendly gives you a special code
You trade that code for an access token
Voilà! You're in!

The key players here are the authorization endpoint and the token endpoint. Remember these; they're your new best friends.

Implementing the Authorization Flow

Initiating the Authorization Request

First up, we need to construct the authorization URL. It's like crafting the perfect invitation:

const authUrl = `https://auth.calendly.com/oauth/authorize?client_id=${CLIENT_ID}&response_type=code&redirect_uri=${REDIRECT_URI}`;

Send your user to this URL, and Calendly will ask them if they want to play ball with your app.

Handling the Authorization Callback

Once the user gives you the thumbs up, Calendly will redirect them back to your REDIRECT_URI with a special gift: the authorization code. It'll be in the URL, so keep your eyes peeled:

const urlParams = new URLSearchParams(window.location.search);
const code = urlParams.get('code');

If something goes wrong (hey, it happens), Calendly will tell you. Make sure to handle those errors with grace.

Exchanging the Authorization Code for Access Token

Now for the grand finale - trading that code for an access token. It's time to make a POST request to the token endpoint:

const response = await fetch('https://auth.calendly.com/oauth/token', {
  method: 'POST',
  headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
  body: new URLSearchParams({
    grant_type: 'authorization_code',
    client_id: CLIENT_ID,
    client_secret: CLIENT_SECRET,
    code,
    redirect_uri: REDIRECT_URI,
  }),
});

const { access_token, refresh_token } = await response.json();

Boom! You've got the keys to the kingdom. Store these tokens somewhere safe - they're your VIP pass to Calendly's API.

Refreshing the Access Token

Access tokens don't last forever, but that's where the refresh token comes in handy. When your access token expires, just use the refresh token to get a new one:

const refreshResponse = await fetch('https://auth.calendly.com/oauth/token', {
  method: 'POST',
  headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
  body: new URLSearchParams({
    grant_type: 'refresh_token',
    client_id: CLIENT_ID,
    client_secret: CLIENT_SECRET,
    refresh_token: STORED_REFRESH_TOKEN,
  }),
});

const { access_token: new_access_token } = await refreshResponse.json();

Pro tip: Set up a system to automatically refresh tokens before they expire. Your future self will thank you.

Making Authenticated Requests to Calendly API

Now that you're authorized, it's time to put that access token to work:

const calendlyResponse = await fetch('https://api.calendly.com/user/me', {
  headers: {
    Authorization: `Bearer ${access_token}`,
  },
});

Remember to play nice with Calendly's rate limits. Nobody likes a party crasher.

Security Considerations

Security isn't just important; it's crucial. Here are some quick tips:

Never expose your Client Secret on the client-side
Use HTTPS everywhere
Consider implementing PKCE for added security
Treat tokens like passwords - keep 'em secret, keep 'em safe

Testing and Debugging

Testing auth flows can be tricky, but don't sweat it. Use tools like Postman to simulate requests, and keep an eye on your browser's network tab. If you hit a snag, double-check your credentials and URLs. Most issues come down to a misplaced character or two.

Conclusion

And there you have it! You've just built a rock-solid auth flow for your Calendly integration. With this foundation, you're ready to build some seriously cool scheduling features. The sky's the limit!

Additional Resources

Want to dive deeper? Check out:

Now go forth and integrate! Your users are waiting for that sweet, sweet scheduling magic. You've got this! 🚀