At calldesk, we've always strived to challenge our platform and push it at its limits. Since we've won the AWS "Architecture of the Year" 2020 Challenge, we thought it would be interesting to share our journey and feedback on how we've recently scaled our platform from 1000 to 5000 phone calls in parallel using AWS, in less than a month. Quite a technical challenge!

We will be writing a series of articles to explain how this challenge was handled as a team. You'll discover how the engineering team organized itself to reach its goal within 2 sprints, what tools we used, the problems we faced, and what solutions we implemented.

This first article aims to give you an overview of the calldesk technology, the architecture, its associated limits, and why it was not an easy task. The following articles will focus on the solutions we've implemented. Stay tuned!

What the engineering team does at calldesk briefly...

At calldesk, the engineering team is working on 2 main products:

• Our AI-powered voice agents, which are the core business of calldesk, and can automate repetitive calls in a customer call center
• Our studio, which is the SaaS cloud based application we've developed to ease voice agents creation and deployment for our customers and partners

The calldesk technology is a cloud architecture designed to be:

• fast: a voice agent needs to understand the caller and respond in real-time. We can't afford a long response time, and that's why we have designed a streaming architecture
• scalable: our business is growing fast thanks to our customers and partners, so we need to handle more and more calls in parallel
• reliable: we are committed to a 99.99% SLA with our customers and partners. No downtime is acceptable.
• maintainable: a lot of updates have to be released in production every week. We need our architecture to embrace changes
• secured: our voice agents are used by banks, insurance, transport, and utility companies. We have access to sensitive data and need to protect it.

These 5 values drive the engineering culture on a daily basis, and we're happy to share with you how we handled this big technical challenge in the past few weeks.

Read also: How to ensure the security of callers' data when you handle millions of calls every year?

What is the big challenge we faced?

Due to the covid-19 pandemic, we've observed that many businesses are currently switching from an on-premise contact center to a cloud-based contact center, in order to adapt to the new remote first environment. This change is not local to France, it is a global change.

calldesk has recently partnered with cloud-based contact center provider leaders such as NICE inContact or Talkdesk to allow them to automate repetitive calls using our AI-powered voice agents.

In this context, we are expecting more and more calls in parallel on our platform. As for now, we were mainly handling phone calls for large French companies (La Poste, OUI.sncf, Enedis, Dalkia, CNP Assurances...). But phone call volumes are way higher when working on the US market, so partnering with these tech giants requires us to scale the capabilities of our platform.