Hussam Alhallak
As a Tax Accountant at Casella Waste Systems, Hussam Alhallak has built a reputation for precision and initiative in indirect tax. From multi-state sales tax filings and excise tax reviews to exemption certificate audits and account reconciliations, Hussam plays a key role in keeping his company compliant and audit-ready. His self-driven project to overhaul exemption documentation significantly reduced risk and improved internal processes.
Hussam’s passion for sales tax is matched by his dedication to learning. He’s earned six accounting certificates, attends ongoing courses, and completed the Basics course in Chicago. He thrives on the complexity of tax law, finding joy in solving regulatory puzzles and understanding the “why” behind the rules.
Originally from Syria, Hussam began his U.S. career in 2017, overcoming language and cultural barriers to become a valued team member and mentor. His resilience, curiosity, and commitment to excellence make him a true Sales Tax Nerd.
Jill Bartlett
As a Senior Tax Specialist in the cybersecurity industry, Jill Bartlett has spent over 14 years mastering the intricacies of sales and use tax. From manually filing multi-state returns to managing over 17,000 tax codes without automation, Jill has tackled complex compliance challenges head-on. Her initiative to reclassify thousands of software SKUs from downloaded to SaaS saved her company from overcharging customers and reduced audit risk.
Jill’s passion for sales tax shines through her constant learning. She attends webinars, state trainings, and reads tax blogs (even on weekends!). She’s known for building tools and trackers that make tax processes more accurate and accessible, and she’s trained cross-functional teams to understand taxability nuances.
The Sales Tax Nerd in Jill thrives when solving puzzles and sharing knowledge. Whether she’s answering questions in the Sales Tax Nerd Community or wearing her Sales Tax Nerd shirt to spark conversations, Jill brings enthusiasm, expertise, and a deep commitment to getting tax right.
Katarina Fallico
As a Legal Advisor in a global digital marketplace, Katarina Fallico has carved out a unique niche at the intersection of law, technology, and tax. Originally trained in VAT law, Katarina transitioned into U.S. sales and use tax in 2020, quickly becoming a driving force behind her company’s compliance transformation. From designing tax logic for platform services to building audit-ready reporting systems, she’s led cross-functional initiatives that blend legal precision with engineering execution.
Katarina’s passion for tax goes beyond regulation. She sees it as a reflection of society’s values. She created a plain-English tax knowledge base for her product and engineering teams, runs onboarding workshops, and personally tests every tax-related feature before release. Her commitment to clarity and collaboration has made her a trusted resource across departments.
The Sales Tax Nerd in Katarina thrives on complexity and curiosity. Whether she’s translating marketplace facilitator rules or comparing pumpkin taxability across states, she brings global perspective, deep insight, and a love of learning to every challenge.
Stefanie Herbert
As an Accounting Manager at CVW Accounting Inc., Stefanie Herbert has become a rising voice in sales tax for the interior design industry. With over 20 years in accounting, Stefanie transitioned from healthcare finance to supporting small businesses, where she quickly recognized the complexity and risk surrounding multi-state sales tax. Her clients often operate across jurisdictions, and Stefanie stepped up to fill a critical gap—educating her team and clients on taxability, nexus, and compliance.
Stefanie’s initiative led her to the Basics course in Chicago, where she deepened her expertise and returned ready to lead internal trainings. She shared key takeaways from the education she received and also highlighted important topics for group discussion, helping identify opportunities to strengthen processes and improve consistency in client work. Based on team feedback, she is exploring ways to enhance internal sales tax resources and establish more consistent standards for areas such as nexus evaluations.
The Sales Tax Nerd in Stefanie thrives on uncovering the “why” behind the rules. Her curiosity, drive, and commitment to learning make her a standout in a field where clarity and confidence are hard-won and deeply needed.
Kaelyn Robinson
As a Finance Administrator, Kaelyn Robinson has built her company’s sales tax program from the ground up. With no prior experience, she took the initiative to research nexus laws, register in nearly 25 states, and implement Avalara AvaTax, all while filing monthly returns and managing exemption certificates solo. Her work transformed a drawer full of paperwork into a fully automated, audit-ready compliance system.
Kaelyn’s passion for sales tax is fueled by curiosity and a love of learning. She’s attended the Basics course twice, participated in Avalara CRUSH, and regularly joins state webinars to stay ahead of legislative changes. She’s also created internal training materials to educate customer service and finance teams, ensuring company-wide compliance.
The Sales Tax Nerd in Kaelyn thrives on complexity. She enjoys solving regulatory puzzles, building scalable systems, and turning messy rules into clean processes. With her MBA nearly complete and her department poised to grow, Kaelyn is shaping the future of sales tax at her company… and loving every minute of it.
