Track sales-tax nexus yourself: a self-hosted alternative to compliance SaaS

Since South Dakota v. Wayfair (2018), physical presence is no longer the line. Cross a state's economic-nexus threshold — usually $100,000 in a rolling 12 months, sometimes a transaction count — and you are legally required to register and collect there, whether or not you have ever set foot in the state. Miss it, and you are liable for the uncollected tax plus penalties and interest.

What the category costs

The tools that watch these thresholds — Avalara, TaxJar, Sovos — fold nexus tracking into broader tax-compliance platforms billed as recurring subscriptions, often scaling with transaction volume or sitting inside a pricier suite you may not need. Most sellers discover the exposure too late precisely because the monitoring lives behind a paid platform they never bought.

The buy-once option

Nexura is a self-hosted sales-tax nexus tracker you purchase once. Import your sales by state and time, and it tracks each state's threshold against a rolling window, flags where you are approaching or have crossed nexus, and alerts you before the deadline — on your own server, with your revenue data staying in your own database.

• No recurring subscription for what is, at its core, a threshold calculator and an alarm clock.
• Your revenue-by-state data stays yours — you are not uploading your entire sales ledger to a tax vendor's cloud to be told you crossed a line.
• One payment, and the monitoring keeps running for every future year.

The honest limit

Nexura tells you where you have nexus and warns you before you cross — it does not register you, file returns, or calculate the tax owed to each jurisdiction. That filing step is where the big compliance platforms earn their fee, and if you are past nexus in a dozen states you may well want one. But the expensive, easy-to-miss part is knowing — and paying a recurring platform just to monitor thresholds you could own the monitoring for is the costly way around it. Nexura's product page is explicit about the boundary before you spend a cent.

Every vendor figure in this category also lives in the Price Observatory — verified, dated, and source-linked, free to cite — and the calculator turns those figures into your own three-year number in ten seconds.