Hopper is a travel booking app used by more than 100 million travelers to find and secure better prices on flights, hotels, homes, and car rentals.
The product is built around a data-driven booking experience, using historical travel pricing data to help users decide when to book.
Beyond price prediction, Hopper offers features such as price freeze and a color-coded deals calendar, helping travelers reduce uncertainty when planning trips.
The product helps travelers:
Track flight and hotel pricesFind cheaper travel datesFreeze prices before bookingBook flights, hotels, homes, and car rentalsMake travel decisions using data-driven predictionsQualifast joined Hopper not as a detached vendor, but as an embedded engineering partner working directly with Hopper’s Android developers.
This allowed the team to contribute to real product features while gradually building deep understanding of Hopper’s mobile architecture, engineering standards, and release process.
Qualifast’s involvement with Hopper was structured around close collaboration with the core Android team.
Rather than working separately on isolated tasks, Qualifast developers became part of Hopper’s day-to-day engineering process.
This embedded model enabled Qualifast developers to:
Contribute to real production featuresWork directly with Hopper’s internal engineersUnderstand the existing Android architectureFollow Hopper’s engineering standardsBuild product knowledge through hands-on deliveryThis approach was especially important for a product with the scale and complexity of Hopper.
A mobile app trusted by tens of millions of travelers requires architectural consistency, strong collaboration, and careful integration with existing systems.
As Qualifast’s role within Hopper matured, the technical scope expanded beyond feature delivery.
One of the most significant contributions was the design and implementation of Hopper’s Android automation testing framework.
The framework was designed to support:
Automated Android testingStandardized testing methodologyValidation across multiple mobile modulesUI Automator based test executionReliable quality checks for a large-scale Android codebaseThe framework was introduced progressively, module by module, allowing it to be validated against real product scenarios as adoption expanded.
This made the solution easier for Hopper’s engineers to trust, understand, and extend inside their normal development workflow.
The result was a unified testing infrastructure that helped improve quality standards across Hopper’s Android application.
The knowledge gained while building Hopper’s Android automation framework was later shared with the wider developer community.
Boris Strandjev, CEO of Qualifast, presented a tech talk focused on Android test automation using UI Automator.
The talk covered lessons from:
Building automation infrastructure for a large-scale Android appRolling out testing frameworks progressivelyUsing UI Automator in production contextsImproving developer adoption of testing toolsBecause the talk was based on real production challenges from the Hopper collaboration, it offered practical lessons rather than theoretical guidance.
This extended the impact of the project beyond Hopper’s internal engineering team and into the broader Android development community.
After building trust and product knowledge inside Hopper’s Android organization, Qualifast took on one of the app’s major product expansions: the hotel booking module.
Hotels represented an important extension of Hopper’s offering, and the Android experience needed to align with the quality and reliability users expected from the platform.
Qualifast contributed to the hotel booking journey across:
Hotel searchHotel listingsHotel details and option explorationBooking flowConfirmed reservation experienceThe work built on top of Hopper’s existing Android foundations rather than introducing an isolated feature architecture.
This required deep understanding of the product internals, established patterns, and the broader mobile system.
By laying this foundation, Qualifast helped Hopper bring a major travel product expansion to Android users.
When the COVID-19 pandemic brought the global travel industry to a near standstill, Hopper had to adapt quickly.
For Qualifast, this meant transitioning out of the project in a way that protected everything built for the hotels module.
The handover process included:
Explaining architectural decisionsDocumenting established patternsWalking through edge casesTraining Hopper’s remaining engineersTransferring ownership of the hotels moduleThe goal was not simply to hand over code, but to transfer the reasoning, context, and product knowledge behind the implementation.
Qualifast worked closely with Hopper’s engineers until they had the confidence and context needed to continue maintaining and evolving the module independently.
The Hopper collaboration required Android engineering inside a mature, high-scale mobile product with strong quality expectations and established architectural patterns.
Qualifast developers worked directly inside Hopper’s Android codebase and contributed to production mobile features.
Android application developmentKotlin-based mobile engineeringFeature development inside existing architectureLarge-scale mobile product collaborationQualifast designed and implemented a standardized Android automation testing framework.
Testing tool: UI AutomatorScope: Cross-module Android testingRollout model: Progressive module-by-module adoptionGoal: Reliable mobile quality validationThe hotel booking work extended Hopper’s Android app into a major new product category.
Hotel search experienceHotel listings and browsingBooking flow implementationReservation confirmation experienceThe engagement relied on close integration with Hopper’s internal development organization.
Model: Embedded team augmentationProcess: Direct collaboration with core Android engineersKnowledge: Hands-on product and architecture learningDelivery: Production feature contributionQualifast supported a structured transition of the hotels module to Hopper’s internal team.
Training: Detailed walkthroughs for Hopper engineersDocumentation: Architecture and implementation knowledge transferOwnership: Prepared internal team for independent maintenanceContinuity: Clean transition during COVID-19 disruptionThe Hopper collaboration demonstrates how embedded engineering partnerships can support mature, high-scale products without disrupting existing development culture.
Qualifast contributed across product development, testing infrastructure, knowledge sharing, and structured handover.
Throughout the partnership, Qualifast helped Hopper:
For global mobile products, successful engineering support depends on more than implementation speed. It requires architectural respect, deep collaboration, and the ability to integrate into existing teams without lowering quality standards.
Qualifast worked as an embedded Android engineering partner inside Hopper’s core mobile development team, contributing to feature development, automation testing infrastructure, hotel booking functionality, and structured knowledge transfer.
Qualifast designed and implemented Hopper’s Android automation testing framework using UI Automator, creating a standardized way to execute automated tests across multiple Android modules.
Qualifast helped build the Android hotel booking experience, including hotel search, listings, booking flows, and reservation confirmation screens while integrating with Hopper’s existing mobile architecture.
Working directly with Hopper’s Android engineers allowed Qualifast developers to deeply understand the product architecture, engineering standards, and release processes while contributing to production features from day one.
The testing framework was introduced progressively, module by module, allowing Hopper’s engineers to validate it in real production scenarios and adopt it naturally within their existing workflows.
Yes. The collaboration also included knowledge sharing through a public Android testing tech talk, as well as structured documentation, training, and handover processes for Hopper’s internal engineers.
When the COVID-19 pandemic disrupted the travel industry, Qualifast worked closely with Hopper’s remaining engineers to transfer ownership of the hotels module through training, walkthroughs, documentation, and architectural knowledge sharing.
The project involved Android development using Kotlin, UI Automator for automation testing, large-scale mobile architecture practices, and collaborative embedded engineering workflows.
The project demonstrates how an external engineering partner can integrate into a mature mobile organization, contribute to production systems, improve testing infrastructure, and support long-term product continuity without disrupting existing engineering culture.
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