Implementing Phone Number Sign-In: A Strategic Move for Customer Acquisition and Fraud Prevention

At Glovo, one of my primary focus areas was enhancing the new user journey. A key initiative I led was implementing phone number authentication, a project driven by a tight five-week deadline. This initiative was vital to tackling several pressing issues that were impeding our growth and frustrating our users.

The Problem: Friction in the Sign-Up Process

When we analyzed our sign-up and installation rates, we found that only 50% of our app downloaders were creating accounts. This figure dropped even lower in African markets, to just 30%, particularly among Android users. The main culprits were the friction and frustration associated with email-based registration methods. Common issues included invalid emails, weak passwords, and forgotten credentials, leading to a poor user experience.

We also noted that email sign-ups had a success rate of just 75%, compared to 90% for social methods such as Google and Apple Sign-in. Many users encountered errors such as “invalid email” or “wrong credentials.” Notably, 81% of sign-up errors were due to “account already exists,” highlighting the need for a more user-friendly registration method.

Another significant issue, equally crucial but unrelated to user experience, was that users could create multiple Glovo accounts using different emails, all linked to a single phone number. At Glovo, user identity was based on email addresses rather than phone numbers. This loophole was exploited by fraudsters and malicious users who created multiple accounts to repeatedly claim first-time user benefits. As part of this initiative, I aimed to tackle this fraud problem by ensuring account uniqueness while avoiding disruption to existing users’ accounts.

Implementation: Rolling Out Phone Number Sign-Up and Log-In

We began by designing a new sign-up flow that allowed users to register using their phone numbers. The process seemed simple: users would enter their phone number, receive a verification code via SMS, and gain instant access to the app. However, this flow could lead to the creation of vulnerable accounts. For example, if someone inherits your phone number, they could access your account that lacks additional verification methods and have access to your personal information and credit card. To address this, we designed different flows and challenges depending on the conditions:

• New device, new phone number
• New device, existing phone number
• Known device, new phone number

For each of these flows, we defined the proper logic to ensure phone number uniqueness (each number was linked to only one account, reducing duplication and fraud), account security, and a smooth user experience.

To ensure a smooth roll-out, we executed a phased approach. We started with a soft launch, enabling the feature for 5% of users globally for two weeks. This allowed us to monitor success metrics and fine-tune the process. Once we were confident in its performance, we increased the coverage to 50% and then to 100%, conducting A/B testing to validate the impact.

The Results: Improved User Experience and Conversion Rates

The results of this initiative were encouraging. By the end of the A/B test, we had successfully improved the sign-up/install rate and the number of new customers. We saw a 1.36% increase in orders with the new login/signup feature.

The streamlined process significantly reduced the friction that users previously experienced with email-based registration. Additionally, enforcing phone number uniqueness helped reduce the number of duplicate accounts, which had been a major issue.

This move also addressed common issues related to account recovery. Previously, users who forgot their passwords faced significant challenges, especially if they no longer had access to their email accounts. With phone number-based recovery, we provided a more reliable and user-friendly solution.

Reflection: A Step Towards Future Enhancements

Implementing phone number sign-up and log-in was a significant step forward in our mission to enhance user experience and drive customer acquisition. By addressing key challenges and aligning with user preferences, we unlocked new growth opportunities for Glovo. Looking back, this initiative not only improved our sign-up rates but also paved the way for future enhancements.