Sr. Engineering ManagerUI Engineer

Michael W Hallman

Hello! With over a decade in the industry, I have found my passion to center around all things experimentation. Whether it's writing tests, building experimentation programs/teams, guiding in-house solutions, or implementing enterprise-level tools, the AB testing world consistently keeps me engaged.

However, that's just one aspect of my experience. This portfolio provides a glimpse into my journey, highlighting a few of my key achievements that have shaped my professional career.

Let's Connect!


Team Building

While at AEO, I undertook the responsibility of establishing and expanding the experimentation team (Analytics & Web Optimization), embarking on a journey that transformed it from a solo endeavor into a fully staffed program comprising over 20 dedicated resources.

As the sole member of the experimentation team initially, I immersed myself in understanding and implementing engineering best practices for AB testing. This period served as a learning curve where I honed my skills and gained invaluable insights into the intricacies of experimentation and implementation of several testing solutions (Adobe Target/Google Optimize/Optimizely Web & Feature).

One of the key challenges faced was advocating for the prioritization of experimentation within a company primarily focused on bricks-and-mortar operations. Demonstrating the inherent value of experimentation in terms of both learning outcomes and accelerated time to market, I effectively communicated its strategic importance.

Through consistent efforts and tangible results, I successfully showcased the benefits of the experimentation program. This evidence led to a pivotal moment where AEO not only recognized the program's value but also increased the budget, a noteworthy achievement considering the concurrent restrictions and reductions in other areas.

The culmination of persistent efforts and proven success saw the experimentation team evolve into a fully staffed program, boasting a diverse and skilled team of over 20 resources. This growth not only reflected the program's success but also underscored its integral role within AEO's overall strategy.

My tenure at AEO was marked by the strategic establishment and growth of the experimentation team, showcasing my ability to navigate challenges, communicate value, and drive transformative change within a corporate setting. This journey stands as a testament to my leadership, strategic vision, and dedication to fostering innovation within organizations.


Content Relationship Architecture

In my role as the Content Architect at AEO, I played a pivotal role in orchestrating the transition from the traditional CMS (Oracle WCS) to the innovative headless CMS solution, Contentstack.

After extensive consultations with design and content authoring teams, I formulated a strategy that placed the marketing message, or "lockup," at the core of the content architecture. This strategic shift laid the foundation for a more efficient and streamlined content management process.

The solution I devised allowed for the creation of marketing messages in a central location, ensuring consistency across various channels and content types. By creating the message once and leveraging it in multiple areas, we established a system that facilitated effortless updates and maintained a cohesive brand message.

To enhance flexibility, I abstracted visual control from the message itself. This approach enabled customization of visual elements specific to each location, ensuring that while the core message remained consistent, its appearance could be tailored for different contexts. This not only maintained brand consistency but also accommodated diverse visual requirements.

As a final touch, I introduced the concept of an entry "library" that housed reusable content. This library significantly reduced bloated assets and minimized the time required to recreate redundant information. The content library became a valuable resource for efficiently managing and reusing content elements, contributing to a more streamlined and resource-efficient content management system.

The implementation of these strategic initiatives not only facilitated a smooth transition to Contentstack but also revolutionized AEO's content management approach. The focus on the "lockup," visual customization, and the content library collectively contributed to enhanced efficiency, reduced redundancy, and improved consistency across all channels.

My role as the Content Architect during AEO's CMS transition reflects my commitment to developing strategic solutions that optimize content management processes. This experience underscores my ability to align technology with business goals, resulting in innovative and efficient solutions that drive organizational success.


As the lead and, at times, sole engineer of the Analytics & Web Optimization team, a significant facet of my role involved overseeing Tealium, a tag management tool, providing the Universal Data Object (UDO). Given the UDO directly powered personalization and AB testing efforts, this relationship worked well.

Upon assuming ownership of Tealium, I observed that its usage had been primarily geared towards feature support, quick fixes, and 3rd party content experiences. Recognizing the need for a more strategic and streamlined approach, I undertook several initiatives to enhance its functionality and align it with the broader objectives.

Key Transformations:

  1. Customizing and Streamlining Data Collection:
    Within the advanced JS extensions, I focused on customizing and streamlining data collection processes. This strategic enhancement ensured that reliable data was consistently collected, forming the foundation for accurate and insightful business reports.
  2. Pruning Unnecessary Extensions/Tags:
    I initiated a comprehensive cleanup by removing all extensions and tags unrelated to data transfer. This not only decluttered the tool but also optimized site performance having removed inefficient 3rd parties integrations.
  3. "utag_sync" Integration for AB Testing:
    Leveraging the capabilities of utag_sync, I introduced helper methods specifically tailored for AB testing. This integration not only streamlined the AB testing processes but also enhanced the overall efficiency of the analytics initiatives.
  4. UDO - Universal Data Object:
    To ensure consistency and clarity, I introduced a syntax standard for the UDO properties. This standardization facilitated better communication across teams and improved the overall manageability of the data structure.
  5. Architectural Enhancements:
    Recognizing the need for scalability, I designed and implemented a robust architecture utilizing Tealium libraries and profiles. This laid the foundation for accommodating and supporting the growing integrations into newly aquired brands.

The transformation of Tealium under my guidance resulted in a more purpose-driven and efficient tool. By aligning its capabilities with the analytics and web optimization goals, we achieved greater clarity, consistency, and scalability, setting the stage for enhanced data management and utilization.

My role in reshaping Tealium reflects my commitment to optimizing tools for specific business objectives. This initiative showcases my ability to not only identify areas for improvement but also to strategically implement changes that align technology with organizational goals, ultimately fostering more efficient and effective analytics and web optimization efforts.

Growing Talent

2023 AEO Summer Interns

Recognizing the pivotal role of talent acquisition in team growth, I took the initiative to create the Engineering Internship Program at AEO. This program aimed not only to attract the best talent but also to provide interns with a comprehensive and immersive experience in the day-to-day life of a UI Engineer.

While the HR department handled the recruiting process, my role extended to creating, organizing, and facilitating the internship program. I wanted to move away from the conventional approach of using interns for mundane tasks and, instead, provide them with a genuine and informative experience.

To achieve this, I designed an 8-week plan that focused on introducing interns to key members across various engineering teams. These introductions preceded their involvement in team ceremonies, ensuring interns had context for what they observed. Each week centered around a different project team, offering a holistic understanding of the engineering landscape.

A crucial element of the program involved interns reviewing the codebase, proposing their own projects, and actively participating in the project's lifecycle. This hands-on approach included peer programming, pull requests, and culminated in a demo to the engineering team. Additionally, I provided constructive feedback on project proposals, fostering a culture of learning through refactoring and pivoting.

To gauge the success of the internship, I established key metrics, including successful pull requests to address production bugs, approval of pull requests for proposed projects, and completion of a team demo for the project. Furthermore, I incorporated the intern's desire to join AEO as a crucial success criterion. A post-internship survey revealed that the intern expressed a strong interest in becoming a part of the AEO family.

The Engineering Internship Program not only attracted top talent but also provided interns with a meaningful experience, contributing to their informed career decisions. The success metrics underscored the program's effectiveness in fostering skill development, collaboration, and a desire to join AEO.

My role in conceptualizing and executing the Engineering Internship Program at AEO exemplifies my commitment to building future talent through innovative and immersive experiences. This initiative reflects my dedication to creating environments where interns can thrive, learn, and ultimately contribute meaningfully to the organization.

Business Value

Experimentation$130M+ Annual Revenue

In my role as the Engineering Program Lead (EPL) for Analytics and AB Testing, I spearheaded the engineering endeavors for a myriad of experiments, steering the Experimentation team towards remarkable success over the years. Notably, in my final year at AEO, the team undertook a pivotal challenge — testing the efficacy of "social proof" messaging and "nudges" in the checkout process.

In response to this directive, I proposed and advised a comprehensive plan, leveraging a Google Cloud Platform (GCP) feed. This strategic approach aimed to dynamically provide copy and add-to-bag data, enhancing the efficiency of the experiment. The implementation of this plan was integral to testing the impact of innovative messaging strategies in real-time.

The outcome of these experiments surpassed expectations, with several variants demonstrating an impressive ~4% increase in conversion rates. The projected cumulative impact of this improvement amounted to an additional $130 million in annual revenue for AEO. This substantial success not only underscored the effectiveness of the experimentation team but also highlighted the tangible impact of strategic engineering initiatives on the organization's bottom line.

My role as the Engineering Program Lead for Analytics and AB Testing reflects my commitment to driving innovation and achieving tangible results. This particular initiative showcased my ability to devise and execute strategic plans that not only meet experimental objectives but also contribute significantly to the financial success of the organization. It stands as a testament to my leadership in leveraging technology to enhance business outcomes.

Personalization$12M Annual Revenue

As an individual contributor, I took on the crucial responsibility of owning the engineering efforts for the personalization endeavors. Leveraging a powerful ensemble of tools including Adobe Target, the customer data profile, Velocity design templates, and Google Cloud Platform (GCP), my mission was to deliver a personalized and tailored experience for users.

Recognizing the paramount importance of speed and flexibility in the realm of personalization, I devised a data-driven framework. This framework, once integrated into the page, had the capability to dynamically generate, position, and customize fully-responsive, personalized content. This strategic approach aimed to not only enhance user engagement but also to adapt swiftly to evolving preferences and behaviors enabling new widgets to be in production within minutes.

The orchestration of this personalized experience was made possible through the integration of Adobe Target, harnessing customer data profiles to gain insights, Velocity design templates for dynamic content creation, and the robust capabilities of GCP for a seamless, scalable data feed.

The implementation of this data-driven framework proved to be a game-changer, enabling personalized landing pages and strategically placed product recommendations across the site. This not only elevated the user experience but also resulted in a substantial $12 million annual increase in revenue, attesting to the project's significant impact on the bottom line.

My role as an individual contributor in the realm of personalization underscores my commitment to leveraging cutting-edge technologies and strategic frameworks. This initiative not only showcases my technical proficiency but also demonstrates my ability to craft dynamic and responsive experiences that resonate with users, ultimately contributing to a substantial increase in annual revenue and the overall success of the digital ecosystem.

Build vs Buy$300K Cost Savings

Embarking on my journey at AEO, I initially immersed myself in the fundamentals of front-end development, diligently hard-coding "web sets" to implement crucial marketing updates. This early experience not only laid a solid foundation for my technical skills but also honed my ability to work swiftly and effectively under pressure.

After a year or two, an opportunity emerged for me to contribute to the AB testing initiatives, which were then outsourced to Brooks Bell. Seizing the chance to expand my skill set, I delved into the intricacies of AB testing, learning extensively from the partnership. Swiftly proving my capability, I assumed full responsibility for the workload. Recognizing my proficiency, the business partners made a strategic decision to terminate the outsourcing contract with Brooks Bell, resulting in an estimated annual saving of $300,000.

This pivotal moment became the turning point in my career trajectory. While the decision between building in-house or outsourcing depends on the context, I demonstrated the tangible benefits of having an AB testing program within the organization. This strategic move not only showcased the value I brought to the table but also set the stage for my journey in creating and growing experimentation programs.

This transformation marked the genesis of my current path, where I have continued to innovate and lead in the realm of experimentation programs. From the foundational front-end development work to steering the transition from outsourcing to in-house AB testing, this journey has been instrumental in shaping my expertise and propelling me towards ongoing success in the dynamic field of experimentation.


FrameworksSee it in action!

AEO Jean Guide

Among my repertoire of impactful solutions, one that stands out prominently is the product guide framework—a versatile tool designed to present diverse product views to users on category pages. This solution seamlessly blended a data-driven approach with user-friendly customization, allowing business users and the design team to independently create, adjust, and maintain product guides without the need for constant engineering intervention.

The essence of this framework lies in its data-driven architecture, which empowers business users to dynamically tailor product guides. By collaborating closely with the design team, I facilitated a seamless process where the visual representation of products could be adapted to suit evolving needs. This innovative approach ensured that the presentation of products on category pages could be finely tuned to align with business objectives and design aesthetics.

At the core of this solution was the utilization of JSON, a powerful and flexible data format. Leveraging JSON, the product guides became fully customizable, allowing for the incorporation of multiple attributes. This flexibility enabled precise adjustments to settings, ensuring that the guides could adapt effortlessly to changing requirements and evolving user experiences.

The implementation of the product guide framework not only streamlined the process of showcasing products on category pages but also empowered non-technical stakeholders to actively participate in the customization process. This not only improved the agility of the system but also significantly reduced the dependency on engineering resources, contributing to a more efficient and collaborative workflow.

The product guide framework exemplifies my commitment to developing solutions that combine technical prowess with user-centric customization. This innovation not only enhanced the visual appeal of product presentations but also revolutionized the way business users and design teams interacted with and adjusted these guides. It stands as a testament to my ability to bridge the gap between technology and user empowerment in creating impactful and versatile solutions.

Process ImprovementsSee it in action!

Master Module

As a pivotal stakeholder in the inaugural Content Management System (CMS) implementation, Oracle WCS, I keenly understood the challenges associated with traditional CMS platforms. The transition to a headless CMS, specifically Contentstack, presented an opportunity to address a significant pain point from the legacy platform – design template flexibility.

Under Oracle WCS, the marketing messages were constrained by a fixed set of content templates, leading to extensive deployment times for new templates or updates. The process involved navigating through design, WCS development, and UI development, resulting in an average timeline of several months.

Recognizing the need for a transformative solution, I focused on two key areas. First, I advocated for a shift from delivering fully formed HTML templates to embracing data-driven templates. Second, I created a dynamic template engine within Contentstack, "Master Module," empowering business users to create and edit templates seamlessly.

The implementation of this solution proved immensely successful, effectively eliminating the need for extensive design and engineering efforts saving an estimated 3 months per request. The Master Module enabled business users to create and leverage templates instantly, revolutionizing the approach to template management.

This strategic shift not only streamlined the template deployment process but also significantly reduced the time and effort previously associated with template updates. The success of this initiative highlights my ability to identify and address critical pain points, leveraging technology to enhance efficiency and empower users.

My role in steering the transition from a traditional CMS to a headless CMS, coupled with the successful implementation of a dynamic template engine, exemplifies my commitment to innovation and efficiency. This achievement stands as a testament to my strategic thinking and ability to drive impactful change within the realm of content management.

Internal ApplicationsSee it in action!

Headless CMS

While my direct experience with app development may be limited, my collaborations with App Engineers have granted me valuable insights into the intricate workings of mobile applications. One standout initiative involved addressing a business need for dynamic updates to marketing content on the AEO and Aerie apps without the need for traditional updates. To meet this challenge, I proposed and implemented a data-driven approach, now known in the industry as "headless" content delivery.

I crafted a JSON structure that could be effortlessly expanded, ensuring backward compatibility. This was crucial to prevent any disruption to the user experience for those who hadn't received the update.

Recognizing the inherent challenges of manually managing the JSON structure, I developed an in-house application to simplify the process for business users. This user-friendly application featured:

  • Forms for easily configuring JSON properties
  • Live previews to visualize content display in the app
  • Timers for scheduling content updates
  • Comprehensive content overview with drag-and-drop functionality for seamless reordering
  • Form validation to ensure accuracy
  • Integration with Git to automate the merging of JSON changes into the repository

Upon successfully implementing the solution, my manager and I pitched the idea to leadership as a new approach to drive all online content. Unfortunately, we were ahead of our time, proposing this concept around 2013.

While the broader adoption of this approach was not immediate, the initiative laid the groundwork for future innovations in content management. The headless CMS and the accompanying application demonstrated the potential to revolutionize content updates, enhance efficiency, and reduce dependency on engineering support.

The headless CMS initiative represents my commitment to finding innovative solutions at the intersection of business needs and technology. Despite being ahead of its time, this project exemplifies my ability to introduce cutting-edge concepts that can potentially reshape industry practices, showcasing a forward-thinking approach to app content management.


Eagle's EliteSee it in action!

Jimmy Hunkele and Michael Hallman were recognized by Roberto Croce and Michael Leedy for their Passion, Innovation and Teamwork. Working above and beyond the call of duty, Jimmy and Michael worked outside of their primary responsibilities to implement Personalized Product Recommendations throughout the AE.COM web experience. Due to their teamwork, this implementation is projected to net over an estimated 12 million in annual revenue and the additional revenue realized has already resulted in significant positive ROI.

Eagle's EliteSee it in action!

Lisa Rusciolelli, Mia Federici, Mike Hallman, Steve Brown, Matt Cipperly, Scott Rupnik, Jessica Berlin and Ethan Holland were recognized for their incredible work with the Live Your Life contest. Nominated for their Passion and Teamwork by Roberto Croce and Michael Leedy, this team of associates went above and beyond in both innovative thinking as well as working tirelessly all day, night, and during their weekends to ensure an on-time, successful launch of AE's Live Your Life BTS sweepstakes campaign. Special thanks to Lisa Rusciolelli for her tremendous leadership in this project. Due to their hard work, currently, the contest has generated $961,067 vs last years, $541,696, resulting in a 77.4% increase in comps.

Op Co SpotlightSee it in action!

Julie Glaros, VP - GMM / AE Direct, recognized 26 Associates across three Departments who worked for over a year to bring a new digital content system to AEO!

The new tool, ContentStack, created process efficiencies and puts the creative power in the right hands. ContentStack gives the designers more creative freedom, allows the content authors to be more nimble and eliminates the need for the developers to support ongoing new module requests. All of these backend improvements will help us deliver a better customer experience.

While there is so much to celebrate around the tool, the real celebration is for the team that worked together to make it happen. Each partner on this team was open minded to each other's opinions, innovative in their approach, and considerate of ways to do business in new ways. They problem-solved and helped each other train, comprehend, and get all their collective needs met within this new tool.

The astounding teamwork, passion and innovation demonstrated by this team resulted in delivering a best in-class tool which will set us up for future success.

High Fives


Ranked in Top 100 Retail Personalization Index by SailThru for personalization features.


Mackenzie Dunn
Associate Manager - Design
American Eagle Outfitters

"I have had the pleasure of working with Mike for 7 years. His knowledge & insights were always consistent and clear that helped our developer-designer relationship be a supportive and innovative one. He is always open to new ideas and a team player in making those ideas come to life with the lowest possible effort and the highest reward for both the business and the customer. From a designers perspective, Mike is an ideal teammate for pushing boundaries and launching successful digital products."

Ashley Dickey
Lead Product Manager
American Eagle Outfitters

"I worked closely with Mike over the last year and a half as my engineering lead and solutions architect supporting A/B testing and third party integrations. Mike's leadership and expertise in this space allowed us to build and grow our testing program exponentially beyond the goals we set in the first year. He's knowledgeable and patient and a solid team player, always addressing challenges with a positive attitude and a viable solution. His contributions were instrumental in building an efficient, effective and, most importantly, happy team. 10/10 recommend!"

Lyndsay Molinaro
Sr. Manager of Portfolio and Release Management
American Eagle Outfitters

"I have worked with Michael Hallman for 13 years at American Eagle. He has really grown over the years from starting as a UI developer to building out an entire AB Testing team and process at American Eagle. I highly recommend Michael as a fantastic leader, co-worker, and innovator in his area of expertise."

Shawn Hazen
Manager Mobile Engineering
American Eagle Outfitters

"Michael has always been one of the most dependable people in the UI team. Excelling at organizing and kicking off projects, never shying away from daunting workloads."

Nate Jara
Director - Web and Mobile Engineering
American Eagle Outfitters

"Michael joined AEO as a frontend developer, working on websets late into the night with our scrappy development team at the time. Since then, Michael has grown into a leader and become a champion for optimization in the webset space as a key player in our Content Strategy team. He was highly influential most recently in leading content architecture with Contentstack, developing a foundation hands-on for our solution to grow and scale for all shopping channels. He has also been a passionate leader in the A/B testing and experimentation area, pioneering efforts to mature our capabilities and integrations through Tealium, Google Optimize, and this year with our switch to Optimizely. Michael was always a strong advocate for his team and the work to better the experiences for our AEO customer."