How to Scale Your Signup API to Handle Explosive User Growth?

At our company, we specialize in designing scalable solutions for high-traffic applications and have extensive experience working across various platforms. Recently, a prominent organization running a fast-growing digital platform approached us with a critical challenge. Their Signup API, initially designed to handle moderate traffic, started to falter under the strain of exponential user growth. Built using NestJS and MySQL, their system faced severe performance bottlenecks, especially during peak signup times.

After analyzing their existing architecture, we identified the root causes of the slowdown and recommended leveraging Amazon SQS to decouple the API layer from the database and enable asynchronous processing. In this blog, we’ll share the challenges they faced, the solution we implemented, and how it transformed their system to effortlessly handle millions of users.

Business Challenges

Initially, our signup API worked fine, but over time, as user growth accelerated, we started facing performance issues. Specifically, direct database inserts to MySQL caused high CPU usage, leading to slow signup times and a poor user experience. the system struggled to handle increased traffic, which was a major roadblock for scaling. Moreover, our architecture was not designed to support millions of concurrent users. Therefore, we needed a solution that would allow us to handle high traffic efficiently.

High Database CPU Usage

Our API relied heavily on synchronous writes to the database. Every signup triggered multiple inserts—not just into the user’s table but also into associated tables like user profiles, devices, and login history. As the number of concurrent signups increased, MySQL struggled to handle the growing load.
The final straw came during a load testing event, where our signup traffic surged by 10x. The database became unresponsive within minutes, leading to a loss of signups. It became clear that our system required a complete architectural overhaul to handle such demands effectively.

Slow Signup Times

Because the database was overburdened, the time required to complete a single signup grew significantly. Users experienced long wait times or even timeouts when attempting to sign up.

Scalability Limitations

Our architecture wasn’t designed with scalability in mind. With each new user, the system’s performance degraded further. This became particularly problematic during marketing campaigns or viral events, where signup rates spiked exponentially.

How we implemented API:

Instead of writing directly to the database, the API now sends signup data to an SQS queue. A dedicated consumer service then polls the SQS queue to process messages and write them to the database. This approach enables the API to respond quickly to users while offloading the heavier processing to a background task. By decoupling these operations, the system efficiently handles large volumes of data without overloading MySQL.

The Results of Scaling Our Signup API

The decision to introduce Amazon SQS into our Signup API architecture was transformative. It addressed the bottlenecks we faced and delivered remarkable improvements across multiple dimensions of our system.
Here’s a detailed look at the measurable impact of this redesign:

Reduced Database Load

One of the most significant outcomes was the dramatic reduction in MySQL CPU usage. By offloading direct database writes to an asynchronous queue, the database no longer faced sudden spikes in traffic during high user signups.

• Before SQS: Each signup triggered immediate writes to multiple tables, overwhelming MySQL during peak traffic.
• After SQS: Database operations were evenly distributed over time as SQS consumers processed messages in batches.
• Result: MySQL operated at optimal levels, freeing up resources for other critical tasks.

Faster Signup Times

With the API no longer tied to synchronous database operations, users experienced near-instant responses.

• Before SQS: The API waited for database inserts to complete, leading to delays, especially during high traffic.
• After SQS: The API immediately returned a successful response after queuing the signup data, regardless of the database load.
• Result: Signup times improved significantly, providing a seamless and faster experience for users.

Improved Scalability

The new architecture was built to handle massive traffic spikes effortlessly. By leveraging SQS, the system is dynamically scaled to process millions of concurrent signups without downtime.

• Before SQS: The system struggled with traffic spikes, often resulting in database crashes or user timeouts.
• After SQS: The queue absorbed the traffic surge, and we scaled up the number of consumers during high load periods to maintain processing speed.
• Result: During a major marketing event, the system successfully handled a 10x increase in traffic without breaking a sweat.

Reliability and Fault Tolerance

SQS added a layer of fault tolerance that was previously missing.

• Messages that couldn’t be processed due to errors or temporary downtime remained in the queue until resolved, ensuring no data was lost.
• The system continued operating smoothly even when consumers were unavailable, as SQS buffered incoming traffic.
• Result: The signup process became more robust and resilient to failures, reducing operational risks.

User Satisfaction

The redesign directly translated into a better user experience:

• Faster signup times and fewer failures meant happier users and increased retention.
• The scalability ensured no one was turned away, even during viral campaigns or traffic surges.

Conclusion: Scaling Signup APIs Made Simple

After implementing our redesigned architecture, the results were transformative:

• Reduced Database Load: By introducing Amazon SQS to decouple processes, MySQL CPU usage dropped significantly, ensuring the database could handle higher traffic without performance degradation.
• Improved Response Times: The asynchronous processing approach reduced API response times by over 50%, delivering a seamless signup experience to users.
• Enhanced Scalability: The system now dynamically adapts to traffic spikes, easily supporting millions of concurrent signups without downtime.

These changes not only optimized performance but also future-proofed the platform for growth, reducing developer intervention and maintenance efforts by over 40%.

Scaling APIs for millions of users requires thoughtful architectural decisions, robust tools, and regular testing. Our journey highlights the importance of decoupling processes, embracing asynchronous designs, and planning for scalability from the outset. If you’re facing similar challenges, consider integrating message queues and asynchronous architectures to unlock the true potential of your platform.

Contact Us

Are you facing similar challenges in your Tech journey? Reach out to us today to explore tailored solutions that align with your unique requirements. Our team of experts is dedicated to empowering your organization with cutting-edge Tech practices and technologies. Let’s embark on a transformative journey together!

Thank you for Reading !! 🙌🏻😁📃, see you in the next blog.🤘

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