Replatforming the tools that help seniors save on property taxes

AARP Foundation | Property Tax-Aide

• 40% fewer clicks to complete an application, on average
• 14 tools rebuilt on React and Ruby on Rails
• 28,000+ people have applied for property tax relief
• $10M+ in relief secured for low-income older adults
• Multi-year partnership

The AARP Foundation serves vulnerable people 50 and older by creating and advancing solutions that help them secure the essentials. Its Property Tax-Aide (PTA) program helps low-income older adults stay in their homes by connecting them with property tax refund and credit programs in their state.

At the core of the program is a suite of custom digital tools: an Eligibility Screener that determines whether a user qualifies for relief programs in their state, and a Form Completion Tool that helps them complete and submit the application.

The Challenge: a system the program had outgrown

The tools launched in 2019 with a different development partner, and the program grew faster than the software underneath it. By 2021, the PTA team had real concerns about quality and scalability, and they engaged The Gnar to assess the current state.

This is where every modernization engagement should start: a diagnosis before a prescription. Our audit of the existing codebase found no integrated testing, security vulnerabilities, no CI/CD pipeline, inconsistent frontend components, unnecessary UX complexity, and interfaces that didn't meet ADA accessibility requirements. Worse, the tools weren't built to scale, so every change was slow, risky, and expensive.

The Decision: modernize or replatform?

Some legacy systems can be saved. Others have to be replaced. The audit made the call clear: replatforming would cost less and carry less risk than rebuilding on top of the existing codebase. Just as important, the program couldn't go dark while we did it. Thousands of older adults relied on these tools every tax season.

So we built a three-phase plan that kept the existing tools running while their replacements took shape:

Phase 1: Discovery and stabilization. A four-week phase where we took ownership of the codebase from the previous firm, stabilized the current tools so they could be used securely, and gathered requirements for the rebuild.

Phase 2: Rebuild while maintaining. Using those requirements, we rebuilt the existing tools with testing, security, and scalability built in from the first commit. In total, 14 tools were rebuilt with React on the front end and Ruby on Rails for the backend and business logic.

Phase 3: New features the old platform couldn't support. Address autocomplete, user accounts, identity management, a Yellowfin BI implementation, and a redesigned UX that cut the clicks required to complete an application by 40% on average.

The Results: a platform with room to grow

After the replatform, The Gnar maintained and updated the tools for every subsequent tax year and built new tools for additional states. The numbers that matter belong to the people the program serves: more than 28,000 applicants, and over $10M in property tax relief secured for older adults who needed it to stay in their homes.

Their team was highly organized and proactive, ensuring that all objectives were met on time and with excellence.

- Krystal Downie, Business Operations Manager, AARP Foundation Property Tax-Aide

How we'd run this engagement today

This project is the blueprint for our Legacy Software Modernization solution: a fixed-price Discovery that diagnoses whether your system needs an overlay or a replatform, phased delivery that keeps the business running, and ongoing support after launch. Today, the build phase also carries our triple guarantee: a fixed price, a guaranteed outcome, and a 12-month bug-free warranty.

Running on a system your business has outgrown?

Tell us where you are. A fixed-price Discovery will tell you whether your system needs an overlay or a rebuild, and what it will cost, before you commit to anything.

Talk to us about modernization or see the Legacy Software Modernization solution