Case Study: High-Profile App Launch

Overview

QualityLogic partnered with a messaging-adjacent mobile software client to load test its application ahead of a major public launch delivered in partnership with a household-name technology company, ensuring the app could withstand a heavy surge of new users without a failed first impression.

TL;DR

• Starting point: an unproven messaging system heading into a high-profile public launch, with no room for a failed first impression
• Approach: custom load testing scripts simulating up to 30,000 concurrent users and 3,200 requests per second, run in tight collaboration with the client’s engineering team
• 1% initial timeout rate found on file uploads and fetches, fixed before launch
• 50% improvement in system performance
• 0% request failure rate at launch
• Outcome: a stable, high-confidence launch delivered on the client’s timeline and budget

The Client

The client builds messaging-adjacent mobile software: an iOS, iPadOS, and macOS application that extends a major platform’s core messaging experience, built on patented technology. The app was heading into a major public launch delivered in partnership with a household-name technology company, which meant the release was already announced to the market before testing even started. There was no quiet rollout option and no room to fix a bad first impression after the fact.

Disclosure: Wondering why there’s no name attached? We’ve been authorized to share the details of this program but are adhering to our non-disclosure agreement to not identify the client by name.

The Problem

The client needed the app to stay highly performant and deliver a smooth experience even under a heavy load of new users in the first days after launch. Given the public partnership and the market attention already on the release, a bad launch wouldn’t just be an embarrassment. It would shape the app’s reputation going forward.

The client evaluated both US-based and offshore testing vendors. Having worked with both before, they decided real-time collaboration and time-zone alignment mattered more for a launch this critical than any cost advantage offshore might offer. They also wanted a partner with deep testing domain expertise who could move fast and stay flexible as the timeline tightened. QualityLogic was the fit on all three counts.

The Approach

QualityLogic worked with the client’s technical stakeholders during the proposal process to pin down requirements and identify gaps before the engagement even started. When the client came back wanting to trim the budget, QualityLogic reworked the approach with them, walking through the tradeoffs of different options and landing on a plan that still delivered high confidence in the app’s readiness.

Once the plan was set, the two teams ran the engagement through a shared Slack channel, daily testing status updates, and live calls during load test runs to catch and triage bottlenecks as they came up.

QualityLogic’s team built JavaScript-based load testing scripts in Grafana k6, which gave the team fine-grained control over test scenarios. That framework supported runs simulating up to 30,000 concurrent users and a peak of 3,200 requests per second.

Testing started asynchronously to establish a baseline read on system stability. That surfaced a 1% timeout rate on file uploads and fetches. Small on paper, but a failure mode that would have made core app functionality behave unpredictably for real users. After the client patched it, QualityLogic moved to synchronous large-scale load tests, running stress test analysis in parallel with the client’s own backend data review. That let the client’s team move fast enough to hit their time-to-market goals.

The Outcome

The client came out of the engagement with a system that was more stable, more performant, and ready for the launch it had already announced to the market. The program hit the client’s time-to-market and cost goals, and also reduced long-term technical debt and surfaced hardware deficiencies the client was able to fix ahead of launch.

The numbers: a 50% improvement in system performance and a request failure rate brought down to 0%.