Power Your App With Inbox Data

Communications features are tablestakes for modern applications — but how you go about building the integration has massive impact on your roadmap and revenue.

When connecting your app to Gmail, Microsoft Exchange, Outlook.com and the rest, consider factors like security implications, ongoing maintenance and support costs, and opportunity costs.


Risks to Building Your Own Email Integration

High opportunity costs and the ongoing cost of maintenance.
Takes up to 12 months for a team of engineers to implement.
Costly, time-consuming security & compliance certifications.
The burden of security infrastructure falls on you.

Should I Build?

Should I Buy?

Connecting your application to just one email service provider (ESP) can take as long as 12 months for a team of four or more engineers. As you build connections to additional ESPs, the number of bugs, server-specific issues and edge-case scenarios compounds.

  • Gmail
  • Exchange
  • Office 365
  • Outlook.com
  • IMAP

Gmail Integration

Connecting your app to Gmail's email, calendar and contacts data might seem simple at first. Ask any developer who has built the integration end-to-end, and they'll tell you that simple features like recurring events, time zones, and email attachments are just the tip of the iceberg. Google's OAuth updates and security concerns add another few weeks or months of development time to your timeline.

Total time to integrate: 3-6 months for a team of 4 engineers.


Exchange Integration

Microsoft Exchange is one of the most widely used ESPs, especially in the enterprise — but it's also one of the most challenging integrations to build. Originally, the Exchange protocol was created for pocket PCs developed in the early 2000's. Today, Exchange uses two main protocols - EAS and EAS to send data in binary XML.

Total time to integrate: 6-12 months for a team of 4 engineers.


Office 365 Integration

The Office 365 APIs are still quite nascent, which means they don't come with out-of-the-box features for email analytics like open tracking and link click tracking. There's also no support for inline images.

Anticipated time to integrate: 3-4 months for a team of 4 engineers to build a feature-limited integration.


Outlook.com Integration

Outlook.com is used by millions across the globe, which makes it an essential part of your MVP for your email integration. However, ongoing support and maintenance costs can rise over-time, and updates to the API can introduce breaking changes.

Time to integrate: 2-3 months for a team of 4 engineers.

IMAP Integration

Building an IMAP implementation will add only email functionality to your app. If you want to support any calendar or contacts sync, you'll need to parse CalDav and CardDAV objects and return them in a consistent way to match the way you handle other ESPs.

Total time to integrate: 12 months for a team of 4 engineers to integrate with the main IMAP providers like iCloud, Fastmail, Yahoo, Mail.ru, and Dovecot.



There are a few costs to consider when evaluating whether to build or buy an integration between your application and ESPs:


1. Costs of operating servers

  1. 2. Support costs troubleshooting user errors and bugs
  2. 3. Ongoing maintenance costs with new ESP versioning
  3. 4. Security costs for compliance certifications (~$75K-$100K)
  4. 5. Opportunity cost of time not spent building other core features

As your platform scales and your user base grows, these costs increase over time


You can save months of engineering time and years of ongoing support by buying an API.

Should I Buy?

Integrating With an API

If you want to go to market faster with an email integration, integrating with a fully supported API is the way to go. The Nylas API was created by developers, for developers, after years of research, exploration, and investigation of a multitude of edge-cases (and solving for them).

The Nylas API for Email, Calendar, & Contacts

The Nylas API connects apps to 100% of ESPs in as a little as four lines of code. Save up to 18 months of development time and focus on the features that are core to your business.


Save valuable engineering time

Save 18-24 months of engineering team time by building on top of the Nylas Email API


Integrate once; connect with many

Power your app with email sync & send across 100% of email providers using just one API


Beat the competition

Go to market faster with full email sync & send features, as well as analytics


Reduce costs

Eliminate ongoing maintenance costs of building a solution yourself


Enjoy enterprise-grade security

Data for each account is fully encrypted and isolated with multi-level permission checks

Six Questions To Help You Decide Whether to Build or Buy

Is there an urgency to build email and calendar functionality into my application?

The fastest option is to integrate using an API.

What is the total cost of ownership for integration?

±$800K-1.2M per year for 4 experienced engineers.

How can I make an immediate impact on customer engagement and retention?

Integrate email, calendar, and contacts data with your product.

Which approach sets me up for success in the longterm?

Using an API will allow your team to focus on new, innovative product features.

What if the person who builds/maintains the integration leaves the company?

You’ll potentially lose months while onboarding a new engineer.

What if our systems have errors or customers aren’t happy?

A team of 5-10 technical customer support people may be required.

Want to Learn More?

Schedule a consultation with a Nylas specialist now.