A product that reconciles Chicago's three-authority stack doesn't automatically handle Alabama's centralized model, or Pennsylvania's state-administered city tax. We built for each pattern separately, on purpose.
True multi-layer stacking: a distributor files to the state, the county, and the city separately. The clearest, highest-value proof case — a product that reconciles this well has demonstrated its core value proposition.
Highest jurisdiction complexity — 3 authorities reconciled per transaction
Not the highest rate, but the highest jurisdiction count in one state — 96 cities and 2 counties, each independent. Proves the product scales to high-fragmentation volume, not just high-complexity stacking.
Volume complexity — dozens of distinct filings statewide
The inverse technical problem: one centralized state-system integration with ALDOR, rather than many local filings. Worth building for as a distinct integration pattern.
One state-system integration instead of many local filings
A narrow single-city edge case — but the "state administers the city's stamp" model requires its own logic even though there's only one local jurisdiction.
Single-city edge case requiring state-administered city-tax logic
Lowest complexity of the group — one add-on layer only — but highest dollar stakes, given NYC's rate layered onto the nation's highest state rate. Low engineering cost for high revenue relevance.
Lowest complexity, highest dollar stakes of the group
State, county, and city rates applied per transaction, versioned as rates change, with a full audit trail of what rate applied when.
Built on the FTA's standardized XML filing schema, so adding a new state extends the platform rather than requiring a rebuild.
Where a jurisdiction stacks — state, county, city — each authority's filing is reconciled against the others automatically, not manually.
Every calculation, filing, and reconciliation step is logged and retrievable — built for the moment a state auditor asks for it.
We'll walk through Chicago's three-authority filing live — the case that shows the product doing its hardest job.