NexusMonitor is described as 'Automatically tracks when e-commerce sellers hit sales tax nexus thresholds in each US state. Since the 2018 Wayfair Supreme Court ruling, every state can require online sellers to collect sales tax once they exceed certain thresholds — typically $100K in sales or' and is an app in the business & commerce category. There are three alternatives to NexusMonitor for Web-based and SaaS. The best NexusMonitor alternative is Avalara, which is free. Other great apps like NexusMonitor are Quaderno and TaxJar.