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How Apartment List is improving buyer-seller marketplace communications with Courier

Apartment List and Courier

With well over four million listings on its marketplace, Apartment List has been a leader in the coordination of buyers and sellers within the rental industry for over a decade. Their mission is to improve the renting experience for everyone by making the process personalized, flexible, and transparent.

Because of how important communication between buyers, sellers, and the app is for a marketplace solution, notifications are a central piece of Apartment List’s software. To handle this important part of every user’s experience, the engineering team at Apartment List built two separate apps. Both, however, were a pain to use and maintain, leading to the company eventually turning to Courier.

We spoke with Apartment List’s Senior Director of Engineering, Peter McInerney, to learn more about the two home-grown solutions, what went into the decision to buy rather than build, and how the team has fared using Courier thus far.

Notifications Drive Apartment List’s Marketplace

A marketplace like Apartment List needs to be able to maintain clear and efficient communication with both buyer and sellers (in this context, leasing agents and renters) to continue to successfully attract more listings as well as demand for them. If a leasing agent can add new listings quickly, make changes to existing ones easily, and monitor interest in real time all at at once, they are likely to increase their total number of units rented, and therefore will continue to add more listings in the future. Renters, on the other hand, need to be able to log into their accounts faster and without obstacles and receive personalized guidance based on selected preferences, which is likely to increase renter traffic on the website. With the need for high quality app-to-user communication in all these instances for leasing agents and renters, notifications are key for creating both supply and demand within the marketplace.

For both types of users, there are two major types of notifications that must be covered: marketing messages and product notifications. Marketing messages involve notes encouraging users to return to the platform and interact in the marketplace. Product notifications cover messaging within and for the product like login information and flags when a renter shows interest in a property. Because of the essential functions of product notifications, they also posed the greatest challenges that the engineering team at Apartment List first tried to approach by building solutions in-house.

Build vs. Buy

Apartment List didn’t know of any vendors at first that could handle product notifications for them, and so they tried to build a notification system in-house with a homegrown Sinatra application called Neeson. This was supplemented with Hadron, which would take input content and specifically render a template for a push notification or email. The Hadron templates were in ERB, which tends to be a major negative for Ruby developers who would prefer to stick to simple HTML, CSS, and Javascript.

Ultimately, inconveniences aside, both of these applications became a pain to use and maintain. Potentially even more importantly, they became such a time suck that the engineers at Apartment List struggled to find time for other engineering projects. “We wanted to build a house, but we didn’t necessarily want to worry about the plumbing,” said Peter as he reflected on the project.

Apartment List needed communications like emails to function as a part of their core product, but found that investing the time and resources on what ended up being a sub-par solution forced them to get tangled in the plumbing issues they wanted to avoid. Peter and his team decided that the best solution was to call the plumber by simply buying the best system from experts in the product communications space so that they could focus on building the house instead. So instead of rebuilding Neeson and Hadron from scratch, the team ultimately decided to buy rather than build when they came across Courier.

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Why Courier?

Courier appeared on Apartment List’s radar as they were beginning to focus on finding better solutions for their product notification system and fulfilled many of the needs Peter was actively looking for. Courier allowed Apartment List’s engineers to use an API-first integration while handling templating, credentials, etc. itself. “We were happy to get out of the business of having to design email templates and all of that awful stuff that comes with it,” Peter added. The Courier designer also made it easier for Apartment List’s own engineers and designers to get into edits for templates through simple WYSIWYG editors.

Apartment List also had an interesting feature called Magic Login, which sent users an email with a unique link to access their accounts. This quickly became an issue as these emails often ended up stuck in spam filters or otherwise inaccessible by the recipients. With Courier, Magic Login was able to evolve in Short code, which allowed renters to use a unique ID to log into Apartment List without any security issues or having to deal with the difference in channels that caused issues for the original feature. Short Code also allowed for a better client portal, which now sends all identification and product communication to leasing agents using Courier.

At the end of the day, ramping up a full notification system with Courier was three weeks faster than figuring out to do with homegrown solutions.

The Road to Success

With Courier, the engineers at Apartment List found their notification system faster to build and easier to maintain. What started as an undertaking by a single team at the company to let Courier handle product notifications also expanded to other teams, leading the company to using the product as a central platform service.


Peter mentioned that he now has a team of happier engineers who plan to stick with Courier in the future!

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