A cheap, developer-first US sales-tax calculation and filing API for small e-commerce sellers fed up with Avalara.
“Market-tested” means a real shipped product or experiment measured the failure directly (a live user count, a dead auction, a documented shutdown). “Predicted” means the verdict is an evidence-based forecast from the receipts below, not a direct measurement.
Loud, receipted anger at incumbents: Avalara's billing and support complaints run overwhelmingly negative on review sites, and TaxJar-refugee threads recur since its Stripe acquisition. The pain is real and documented.
The refugees have already been caught twice. Stripe Tax sits inside the checkout stack most small sellers already use — a free-enough, zero-integration floor. And the venture round already happened: Anrok, Kintsugi, Zamp, and Numeral are all funded, all competing for exactly the Avalara-refugee segment, with sales teams and compliance staff you will not match. The killer detail is accuracy liability: rooftop-level rate accuracy across ~13,000 US jurisdictions is continuously human-maintained data — get one district wrong and your customer eats an audit. That maintenance treadmill is the actual product, and it is why every serious entrant raised money instead of bootstrapping.
If the funded cohort consolidated upmarket and Stripe Tax's coverage stopped serving SMB self-serve, a gap could open — but the jurisdiction-data maintenance liability is structural and would remain the true cost of entry.
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